主頁 > 資料庫 > 學習Hibernate5 JPA這一篇就夠了

學習Hibernate5 JPA這一篇就夠了

2020-11-16 19:19:06 資料庫

目錄

    • 第一章 Hibernate5 JPA快速入門
      • 1.1、Hibernate5 JPA概述
      • 1.2、Hibernate5 JPA下載
      • 1.3、Hibernate5 JPA工程搭建
      • 1.4、Hibernate5 JPA增刪改查
      • 1.5、Hibernate5 JPA工具類
    • 第二章 Hibernate5 JPA核心物件
      • 2.1、Persistence
      • 2.2、EntityManagerFactory
      • 2.3、EntityManager
      • 2.4、EntityTransaction
    • 第三章 Hibernate5 JPA映射配置
      • 3.1、一對多關聯
        • 3.1.1、修改物體
        • 3.1.2、測驗代碼
      • 3.2、多對多關聯
        • 3.2.1、創建物體
        • 3.2.2、測驗代碼
      • 3.3、一對一關聯
        • 3.3.1、創建物體
        • 3.3.2、測驗代碼
    • 第四章 Hibernate5 JPA的JPQL查詢
      • 4.1、簡單查詢
      • 4.2、別名查詢
      • 4.3、排序查詢
      • 4.4、條件查詢
      • 4.5、投影查詢
      • 4.6、分頁查詢
      • 4.7、分組查詢
      • 4.8、多表查詢


配套資料,免費下載
鏈接:https://pan.baidu.com/s/1YvoPpZGrZfqHspGUPKtn0w
提取碼:nsmt
復制這段內容后打開百度網盤手機App,操作更方便哦

第一章 Hibernate5 JPA快速入門

1.1、Hibernate5 JPA概述

JPA的全稱是Java Persistence API, 即Java 持久化API,是SUN公司推出的一套基于ORM的規范,內部是由一系列的介面和抽象類構成,JPA通過JDK 5.0注解描述物件-關系表的映射關系,并將運行期的物體物件持久化到資料庫中

fd5e9c1f88bcdb6c41f6685998b44e0f068.jpg /></p> 
<p>但是JPA僅僅只是一套介面規范和抽象類,并不能真正的去干活,因此,就有很多廠商實作了JPA的規范,提供了相應的技術支持,就類似實作了JDBC的MySQL驅動,而本節課程將采用Hibernate實作作為驅動使用,因此我稱之為Hibernate5 JPA</p> 
<h3>1.2、Hibernate5 JPA下載</h3> 
<p>官方網址:hibernate orm</p> 
<p>目錄介紹:</p> 
<p>hibernate-release-5.0.7.Final檔案夾介紹:</p> 
<p><img src=

hibernate-release-5.0.7.Final\lib檔案夾介紹:

image-20200808110712846

1.3、Hibernate5 JPA工程搭建

前邊學習的Hibernate,接下來進行工程搭建,根Hibernate相比,它只需要再多加入一個包就行

把下面四個檔案夾的內容全部拷貝到lib中

  • hibernate-release-5.0.7.Final\lib\required

image-20200804232427671

  • hibernate-release-5.0.7.Final\lib\optional\c3p0

image-20200804231638012

  • hibernate-release-5.0.7.Final\lib\jpa

image-20200808105905572

  • 日志記錄包

image-20200804232406439

  • 資料庫驅動

image-20200805105713238

把下面五個檔案夾的內容全部拷貝到lib中后,全部選中,右鍵Build Path一下

image-20200808111218855

Java工程搭建好了以后,我們需要有一個資料庫(hibernate_jpa)和兩張表用于測驗:

crm_cst_customer(客戶表)

CREATE TABLE `cst_customer` (
  `cust_id` BIGINT(32) NOT NULL AUTO_INCREMENT COMMENT '客戶編號(主鍵)',
  `cust_name` VARCHAR(32) DEFAULT NULL COMMENT '客戶名稱',
  `cust_source` VARCHAR(32) DEFAULT NULL COMMENT '客戶資訊來源',
  `cust_industry` VARCHAR(32) DEFAULT NULL COMMENT '客戶所屬行業',
  `cust_level` VARCHAR(32) DEFAULT NULL COMMENT '客戶級別',
  `cust_phone` VARCHAR(64) DEFAULT NULL COMMENT '固定電話',
  `cust_mobile` VARCHAR(16) DEFAULT NULL COMMENT '移動電話',
  PRIMARY KEY (`cust_id`)
) ENGINE=INNODB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

crm_cst_linkman(聯系人表)

CREATE TABLE `cst_linkman` (
  `lkm_id` BIGINT(32) NOT NULL AUTO_INCREMENT COMMENT '聯系人編號(主鍵)',
  `lkm_name` VARCHAR(16) DEFAULT NULL COMMENT '聯系人姓名',
  `lkm_gender` CHAR(1) DEFAULT NULL COMMENT '聯系人性別',
  `lkm_phone` VARCHAR(16) DEFAULT NULL COMMENT '聯系人辦公電話',
  `lkm_mobile` VARCHAR(16) DEFAULT NULL COMMENT '聯系人手機',
  `lkm_email` VARCHAR(64) DEFAULT NULL COMMENT '聯系人郵箱',
  `lkm_qq` VARCHAR(16) DEFAULT NULL COMMENT '聯系人qq',
  `lkm_position` VARCHAR(16) DEFAULT NULL COMMENT '聯系人職位',
  `lkm_memo` VARCHAR(512) DEFAULT NULL COMMENT '聯系人備注',
  `lkm_cust_id` BIGINT(32) NOT NULL COMMENT '客戶id',
  PRIMARY KEY (`lkm_id`),
  KEY `FK_cst_linkman_lkm_cust_id` (`lkm_cust_id`),
  CONSTRAINT `FK_cst_linkman_lkm_cust_id` FOREIGN KEY (`lkm_cust_id`) REFERENCES `cst_customer` (`cust_id`) ON DELETE NO ACTION ON UPDATE NO ACTION
) ENGINE=INNODB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

在Java工程的src路徑下創建一個名為META-INF的檔案夾,在此檔案夾下創建一個名為persistence.xml的組態檔

通用組態檔(掌握):

persistence.xml(全路徑:/hibernate_jpa/src/META-INF/persistence.xml)

<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://java.sun.com/xml/ns/persistence  
    http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd"
	version="2.0">
	<!-- 
		配置持久化單元
			* name				:持久化單元名稱
			* transaction-type	:持久化單元事務型別
				JTA				:開啟JTA分布式事務
				RESOURCE_LOCAL	:開啟本地事務
	 -->
	<persistence-unit name="myJpa" transaction-type="RESOURCE_LOCAL">
		<!-- 配置JPA服務提供商 -->
		<provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
		<!-- 配置JPA的基本引數 -->
		<properties>
			<!-- 配置資料庫驅動 -->
			<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver" />
			<!-- 配置資料庫地址 -->
			<property name="javax.persistence.jdbc.url" value="jdbc:mysql://127.0.0.1:3306/hibernate_jpa" />
			<!-- 配置資料庫賬戶 -->
			<property name="javax.persistence.jdbc.user" value="root" />
			<!-- 配置資料庫密碼 -->
			<property name="javax.persistence.jdbc.password" value="root" />
			
			<!-- 配置JPA服務提供商可選引數 -->
			<property name="hibernate.show_sql" value="true" />
			<property name="hibernate.format_sql" value="true" />
			<property name="hibernate.hbm2ddl.auto" value="create" />
		</properties>
	</persistence-unit>
</persistence>

整合C3P0連接池版本組態檔(了解):

<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://java.sun.com/xml/ns/persistence  
    http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd"
	version="2.0">
	<!-- 
		配置持久化單元
			* name				:持久化單元名稱
			* transaction-type	:持久化單元事務型別
				JTA				:開啟JTA分布式事務
				RESOURCE_LOCAL	:開啟本地事務
	 -->
	<persistence-unit name="myJpa" transaction-type="RESOURCE_LOCAL">
		<!-- 配置JPA服務提供商 -->
		<provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
		<!-- 配置JPA的基本引數 -->
		<properties>
			<!-- Hibernate JPA基本配置 -->
			<property name="hibernate.connection.driver_class" value="com.mysql.jdbc.Driver" />
			<property name="hibernate.connection.url" value="jdbc:mysql://127.0.0.1:3306/hibernate_jpa" />
			<property name="hibernate.connection.username" value="root" />
			<property name="hibernate.connection.password" value="root" />
			<property name="hibernate.connection.isolation" value="4" />
			<property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect" />
			<property name="hibernate.current_session_context_class" value="thread" />

			<!-- Hibernate JPA可選配置 -->
			<property name="hibernate.show_sql" value="true" />
			<property name="hibernate.format_sql" value="true" />
			<property name="hibernate.hbm2ddl.auto" value="create" />

			<!-- Hibernate JPA整合C3P0資料庫連接池 -->
			<property name="hibernate.connection.provider_class" value="org.hibernate.connection.C3P0ConnectionProvider" />
			<!-- 資料庫連接池的最小連接數 -->
			<property name="c3p0.min_size" value="5" />
			<!-- 資料庫連接池的最大連接數 -->
			<property name="c3p0.max_size" value="30" />
			<!-- 最大空閑時間,60秒內未使用則連接被丟棄,若為0則永不丟棄,Default: 0 -->
			<property name="c3p0.maxIdleTime" value="60" />
			<!-- 獲得連接的超時時間,如果超過這個時間,會拋出例外,單位毫秒 -->
			<property name="c3p0.timeout" value="1800" />
			<!-- 最大的PreparedStatement的數量 -->
			<property name="c3p0.max_statements" value="50" />
			<!-- 每隔120秒檢查連接池里的空閑連接,單位是秒 -->
			<property name="c3p0.idle_test_period" value="120" />
			<!-- 當連接池里面的連接用完的時候,C3P0一下獲取的新的連接數 -->
			<property name="c3p0.acquire_increment" value="1" />
			<!-- 是否每次都驗證連接是否可用 -->
			<property name="c3p0.validate" value="false" />
		</properties>
	</persistence-unit>
</persistence>

對于本節課程來說,使用哪一個都可以,但是第一個更通用,更簡單,我們采用第一個,組態檔有了以后,我們需要撰寫物體類跟資料庫表的映射關系

Customer.java(全路徑:/hibernate_jpa/src/com/caochenlei/hibernate/jpa/Customer.java)

package com.caochenlei.hibernate.jpa;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

/**
 * @Entity	:宣告是一個物體類
 * @Table	:配置物體類和表的映射關系
 * 	* name	:配置資料庫表的名稱
 */
@Entity
@Table(name = "cst_customer")
public class Customer {

	/**
	 * @Id				:宣告主鍵的配置
	 * @GeneratedValue	:配置主鍵的生成策略
	 *      strategy:
	 *          GenerationType.IDENTITY	:自增(底層資料庫必須支持自動增長),mysql
	 *          GenerationType.SEQUENCE	:序列(底層資料庫必須支持序列),oracle
	 *          GenerationType.TABLE	:JPA提供的一種機制,通過一張資料庫表的形式幫助我們完成主鍵自增
	 *          GenerationType.AUTO		:由程式自動的幫助我們選擇主鍵生成策略
	 * @Column			:配置屬性和欄位的映射關系
	 * 		name		:資料庫表中欄位的名稱
	 */
	@Id
	@GeneratedValue(strategy = GenerationType.IDENTITY)
	@Column(name = "cust_id")
	private Long custId;

	@Column(name = "cust_name")
	private String custName;

	@Column(name = "cust_source")
	private String custSource;

	@Column(name = "cust_industry")
	private String custIndustry;

	@Column(name = "cust_level")
	private String custLevel;

	@Column(name = "cust_phone")
	private String custPhone;

	@Column(name = "cust_mobile")
	private String custMobile;

	public Long getCustId() {
		return custId;
	}

	public void setCustId(Long custId) {
		this.custId = custId;
	}

	public String getCustName() {
		return custName;
	}

	public void setCustName(String custName) {
		this.custName = custName;
	}

	public String getCustSource() {
		return custSource;
	}

	public void setCustSource(String custSource) {
		this.custSource = custSource;
	}

	public String getCustIndustry() {
		return custIndustry;
	}

	public void setCustIndustry(String custIndustry) {
		this.custIndustry = custIndustry;
	}

	public String getCustLevel() {
		return custLevel;
	}

	public void setCustLevel(String custLevel) {
		this.custLevel = custLevel;
	}

	public String getCustPhone() {
		return custPhone;
	}

	public void setCustPhone(String custPhone) {
		this.custPhone = custPhone;
	}

	public String getCustMobile() {
		return custMobile;
	}

	public void setCustMobile(String custMobile) {
		this.custMobile = custMobile;
	}

	@Override
	public String toString() {
		return "Customer [custId=" + custId + ", custName=" + custName + ", custSource=" + custSource + ", custIndustry=" + custIndustry + ", custLevel=" + custLevel + ", custPhone=" + custPhone + ", custMobile=" + custMobile + "]";
	}

}

LinkMan.java(全路徑:/hibernate_jpa/src/com/caochenlei/hibernate/jpa/LinkMan.java)

package com.caochenlei.hibernate.jpa;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Table;

@Entity
@Table(name = "cst_linkman")
public class LinkMan {

	@Id
	@GeneratedValue(strategy = GenerationType.IDENTITY)
	@Column(name = "lkm_id")
	private Long lkmId;

	@Column(name = "lkm_name")
	private String lkmName;

	@Column(name = "lkm_gender")
	private String lkmGender;

	@Column(name = "lkm_phone")
	private String lkmPhone;

	@Column(name = "lkm_mobile")
	private String lkmMobile;

	@Column(name = "lkm_email")
	private String lkmEmail;

	@Column(name = "lkm_qq")
	private String lkmQq;

	@Column(name = "lkm_position")
	private String lkmPosition;

	@Column(name = "lkm_memo")
	private String lkmMemo;

	public Long getLkmId() {
		return lkmId;
	}

	public void setLkmId(Long lkmId) {
		this.lkmId = lkmId;
	}

	public String getLkmName() {
		return lkmName;
	}

	public void setLkmName(String lkmName) {
		this.lkmName = lkmName;
	}

	public String getLkmGender() {
		return lkmGender;
	}

	public void setLkmGender(String lkmGender) {
		this.lkmGender = lkmGender;
	}

	public String getLkmPhone() {
		return lkmPhone;
	}

	public void setLkmPhone(String lkmPhone) {
		this.lkmPhone = lkmPhone;
	}

	public String getLkmMobile() {
		return lkmMobile;
	}

	public void setLkmMobile(String lkmMobile) {
		this.lkmMobile = lkmMobile;
	}

	public String getLkmEmail() {
		return lkmEmail;
	}

	public void setLkmEmail(String lkmEmail) {
		this.lkmEmail = lkmEmail;
	}

	public String getLkmQq() {
		return lkmQq;
	}

	public void setLkmQq(String lkmQq) {
		this.lkmQq = lkmQq;
	}

	public String getLkmPosition() {
		return lkmPosition;
	}

	public void setLkmPosition(String lkmPosition) {
		this.lkmPosition = lkmPosition;
	}

	public String getLkmMemo() {
		return lkmMemo;
	}

	public void setLkmMemo(String lkmMemo) {
		this.lkmMemo = lkmMemo;
	}

	@Override
	public String toString() {
		return "LinkMan [lkmId=" + lkmId + ", lkmName=" + lkmName + ", lkmGender=" + lkmGender + ", lkmPhone=" + lkmPhone + ", lkmMobile=" + lkmMobile + ", lkmEmail=" + lkmEmail + ", lkmQq=" + lkmQq + ", lkmPosition=" + lkmPosition + ", lkmMemo=" + lkmMemo + "]";
	}

}

1.4、Hibernate5 JPA增刪改查

CustomerJPATest.java(全路徑:/hibernate_jpa/src/com/caochenlei/hibernate/jpa/CustomerJPATest.java)

package com.caochenlei.hibernate.jpa;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.EntityTransaction;
import javax.persistence.Persistence;

import org.junit.Test;

public class CustomerJPATest {

	/**
	 * 運行之前,修改hibernate.hbm2ddl.auto=create
	 * 保存操作
	 */
	@Test
	public void testSave() {
		// 獲取物體管理器工廠		
		EntityManagerFactory entityManagerFactory = Persistence.createEntityManagerFactory("myJpa");
		// 獲取物體管理器
		EntityManager entityManager = entityManagerFactory.createEntityManager();
		// 獲取事務
		EntityTransaction transaction = entityManager.getTransaction();
		// 開啟事務
		transaction.begin();
		// 創建物體物件并保存
		Customer customer1 = new Customer();
		customer1.setCustName("張三");
		entityManager.persist(customer1);

		Customer customer2 = new Customer();
		customer2.setCustName("李四");
		entityManager.persist(customer2);

		Customer customer3 = new Customer();
		customer3.setCustName("王五");
		entityManager.persist(customer3);
		// 提交事務
		transaction.commit();
		// 釋放資源
		entityManager.close();
		entityManagerFactory.close();
	}

	/**
	 * 運行之前,修改hibernate.hbm2ddl.auto=update
	 * 立即查詢操作
	 */
	@Test
	public void testQuery1() {
		// 獲取物體管理器工廠		
		EntityManagerFactory entityManagerFactory = Persistence.createEntityManagerFactory("myJpa");
		// 獲取物體管理器
		EntityManager entityManager = entityManagerFactory.createEntityManager();
		// 獲取事務
		EntityTransaction transaction = entityManager.getTransaction();
		// 開啟事務
		transaction.begin();
		// 查詢物體并輸出
		Customer customer = entityManager.find(Customer.class, 2L);
		System.out.println(customer);
		// 提交事務
		transaction.commit();
		// 釋放資源
		entityManager.close();
		entityManagerFactory.close();
	}

	/**
	 * 運行之前,修改hibernate.hbm2ddl.auto=update
	 * 延遲查詢操作
	 */
	@Test
	public void testQuery2() {
		// 獲取物體管理器工廠		
		EntityManagerFactory entityManagerFactory = Persistence.createEntityManagerFactory("myJpa");
		// 獲取物體管理器
		EntityManager entityManager = entityManagerFactory.createEntityManager();
		// 獲取事務
		EntityTransaction transaction = entityManager.getTransaction();
		// 開啟事務
		transaction.begin();
		// 查詢物體并輸出
		Customer customer = entityManager.getReference(Customer.class, 2L);
		System.out.println(customer);
		// 提交事務
		transaction.commit();
		// 釋放資源
		entityManager.close();
		entityManagerFactory.close();
	}

	/**
	 * 運行之前,修改hibernate.hbm2ddl.auto=update
	 * 洗掉操作
	 */
	@Test
	public void testDelete() {
		// 獲取物體管理器工廠		
		EntityManagerFactory entityManagerFactory = Persistence.createEntityManagerFactory("myJpa");
		// 獲取物體管理器
		EntityManager entityManager = entityManagerFactory.createEntityManager();
		// 獲取事務
		EntityTransaction transaction = entityManager.getTransaction();
		// 開啟事務
		transaction.begin();
		// 查詢物體并洗掉
		Customer customer = entityManager.find(Customer.class, 1L);
		entityManager.remove(customer);
		// 提交事務
		transaction.commit();
		// 釋放資源
		entityManager.close();
		entityManagerFactory.close();
	}

	/**
	 * 運行之前,修改hibernate.hbm2ddl.auto=update
	 * 更新操作
	 */
	@Test
	public void testUpdate() {
		// 獲取物體管理器工廠		
		EntityManagerFactory entityManagerFactory = Persistence.createEntityManagerFactory("myJpa");
		// 獲取物體管理器
		EntityManager entityManager = entityManagerFactory.createEntityManager();
		// 獲取事務
		EntityTransaction transaction = entityManager.getTransaction();
		// 開啟事務
		transaction.begin();
		// 查詢物體并更新
		Customer customer = entityManager.find(Customer.class, 2L);
		customer.setCustSource("電視廣告");
		entityManager.merge(customer);
		// 提交事務
		transaction.commit();
		// 釋放資源
		entityManager.close();
		entityManagerFactory.close();
	}

}

1.5、Hibernate5 JPA工具類

JPAUtil.java(全路徑:/hibernate_jpa/src/com/caochenlei/hibernate/jpa/JPAUtil.java)

package com.caochenlei.hibernate.jpa;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;

public class JPAUtil {

	private static EntityManagerFactory entityManagerFactory;

	static {
		entityManagerFactory = Persistence.createEntityManagerFactory("myJpa");
	}

	public static EntityManager getEntityManager() {
		return entityManagerFactory.createEntityManager();
	}

}

第二章 Hibernate5 JPA核心物件

2.1、Persistence

Persistence物件主要作用是用于獲取EntityManagerFactory物件的 ,通過呼叫該類的createEntityManagerFactory靜態方法,根據組態檔中持久化單元名稱創建EntityManagerFactory,

2.2、EntityManagerFactory

EntityManagerFactory 介面主要用來創建 EntityManager 實體,

2.3、EntityManager

在 JPA 規范中,EntityManager是完成持久化操作的核心物件,物體類作為普通 java物件,只有在呼叫 EntityManager將其持久化后才會變成持久化物件,EntityManager物件在一組物體類與底層資料源之間進行 O/R 映射的管理,它可以用來管理和更新 Entity Bean,根椐主鍵查找 Entity Bean, 還可以通過JPQL陳述句查詢物體,我們可以通過呼叫EntityManager的方法完成獲取事務,以及持久化資料庫的操作,例如:

  • getTransaction:獲取事務物件
  • persist:保存操作
  • merge:更新操作
  • remove:洗掉操作
  • find/getReference:根據id查詢

2.4、EntityTransaction

在 JPA 規范中,EntityTransaction是完成事務操作的核心物件,對于EntityTransaction在我們的Java代碼中承接的功能比較簡單,

  • begin:開啟事務
  • commit:提交事務
  • rollback:回滾事務

第三章 Hibernate5 JPA映射配置

image-20200806220635419

3.1、一對多關聯

3.1.1、修改物體

修改Customer.java(全路徑:/hibernate_jpa/src/com/caochenlei/hibernate/jpa/Customer.java)

在toString方法的下面添加多的集合

/**
 * 一對多:一的一方配置多的集合
 * @OneToMany	:映射一對多
 * 	* fetch		:抓取策略
 * 		FetchType.LAZY		:延遲加載(默認)
 * 		FetchType.EAGER		:迫切查詢(多表連接查詢)
 * 	* cascade	:級聯操作
 * 		CascadeType.PERSIST	:級聯保存
 * 		CascadeType.MERGE	:級聯更新
 * 		CascadeType.REMOVE	:級聯洗掉
 * 		CascadeType.ALL		:全部支持
 *  * mappedBy	:放棄外鍵維護
 */
@OneToMany(fetch = FetchType.EAGER, cascade = CascadeType.ALL, mappedBy = "customer")
private Set<LinkMan> linkMans = new HashSet<LinkMan>();

public Set<LinkMan> getLinkMans() {
	return linkMans;
}

public void setLinkMans(Set<LinkMan> linkMans) {
	this.linkMans = linkMans;
}

修改LinkMan.java(全路徑:/hibernate_jpa/src/com/caochenlei/hibernate/jpa/LinkMan.java)

在toString方法的下面添加一的物件

/**
 * 多對一:多的一方配置一的物件
 * @ManyToOne	:映射多對一
 * 	* fetch		:抓取策略
 * 		FetchType.LAZY		:延遲加載(默認)
 * 		FetchType.EAGER		:迫切查詢(多表連接查詢)
 * 	* cascade	:級聯操作
 * 		CascadeType.PERSIST	:級聯保存
 * 		CascadeType.MERGE	:級聯更新
 * 		CascadeType.REMOVE	:級聯洗掉
 * 		CascadeType.ALL		:全部支持
 * @JoinColumn	:設定兩張表之間外鍵列
 * 		name				;外鍵的名稱
 */
@ManyToOne(fetch = FetchType.EAGER, cascade = CascadeType.ALL)
@JoinColumn(name = "lkm_cust_id")
private Customer customer = new Customer();

public Customer getCustomer() {
	return customer;
}

public void setCustomer(Customer customer) {
	this.customer = customer;
}

3.1.2、測驗代碼

OneToManyTest.java(全路徑:/hibernate_jpa/src/com/caochenlei/hibernate/jpa/OneToManyTest.java)

package com.caochenlei.hibernate.jpa;

import java.util.Set;

import javax.persistence.EntityManager;
import javax.persistence.EntityTransaction;

import org.junit.Test;

public class OneToManyTest {

	/**
	 * 運行之前,修改hibernate.hbm2ddl.auto=create
	 * 保存客戶級聯保存聯系人
	 */
	@Test
	public void test1() {
		EntityManager entityManager = JPAUtil.getEntityManager();
		EntityTransaction transaction = entityManager.getTransaction();
		transaction.begin();

		// 創建兩個客戶
		Customer customer1 = new Customer();
		customer1.setCustName("張三");
		Customer customer2 = new Customer();
		customer2.setCustName("李四");

		// 創建三個聯系人
		LinkMan linkMan1 = new LinkMan();
		linkMan1.setLkmName("鳳姐");
		LinkMan linkMan2 = new LinkMan();
		linkMan2.setLkmName("如花");
		LinkMan linkMan3 = new LinkMan();
		linkMan3.setLkmName("旺財");

		customer1.getLinkMans().add(linkMan1);
		customer1.getLinkMans().add(linkMan2);
		customer2.getLinkMans().add(linkMan3);
		linkMan1.setCustomer(customer1);
		linkMan2.setCustomer(customer1);
		linkMan3.setCustomer(customer2);

		entityManager.persist(customer1);
		entityManager.persist(customer2);

		transaction.commit();
		entityManager.close();
	}

	/**
	 * 運行之前,修改hibernate.hbm2ddl.auto=create
	 * 保存聯系人級聯保存客戶
	 */
	@Test
	public void test2() {
		EntityManager entityManager = JPAUtil.getEntityManager();
		EntityTransaction transaction = entityManager.getTransaction();
		transaction.begin();

		// 創建兩個客戶
		Customer customer1 = new Customer();
		customer1.setCustName("張三");
		Customer customer2 = new Customer();
		customer2.setCustName("李四");

		// 創建三個聯系人
		LinkMan linkMan1 = new LinkMan();
		linkMan1.setLkmName("鳳姐");
		LinkMan linkMan2 = new LinkMan();
		linkMan2.setLkmName("如花");
		LinkMan linkMan3 = new LinkMan();
		linkMan3.setLkmName("旺財");

		customer1.getLinkMans().add(linkMan1);
		customer1.getLinkMans().add(linkMan2);
		customer2.getLinkMans().add(linkMan3);
		linkMan1.setCustomer(customer1);
		linkMan2.setCustomer(customer1);
		linkMan3.setCustomer(customer2);

		entityManager.persist(linkMan1);
		entityManager.persist(linkMan2);
		entityManager.persist(linkMan3);

		transaction.commit();
		entityManager.close();
	}

	/**
	 * 運行之前,修改hibernate.hbm2ddl.auto=update
	 * 查詢客戶級聯查詢聯系人
	 */
	@Test
	public void test3() {
		EntityManager entityManager = JPAUtil.getEntityManager();
		EntityTransaction transaction = entityManager.getTransaction();
		transaction.begin();

		Customer customer = entityManager.find(Customer.class, 1L);
		System.out.println(customer);

		Set<LinkMan> linkMans = customer.getLinkMans();
		for (LinkMan linkMan : linkMans) {
			System.out.println(linkMan);
		}

		transaction.commit();
		entityManager.close();
	}

	/**
	 * 運行之前,修改hibernate.hbm2ddl.auto=update
	 * 查詢聯系人級聯查詢客戶
	 */
	@Test
	public void test4() {
		EntityManager entityManager = JPAUtil.getEntityManager();
		EntityTransaction transaction = entityManager.getTransaction();
		transaction.begin();

		LinkMan linkMan = entityManager.find(LinkMan.class, 1L);
		System.out.println(linkMan);

		Customer customer = linkMan.getCustomer();
		System.out.println(customer);

		transaction.commit();
		entityManager.close();
	}

	/**
	 * 運行之前,修改hibernate.hbm2ddl.auto=update
	 * 修改客戶、修改聯系人,保存客戶級聯保存聯系人
	 */
	@Test
	public void test5() {
		EntityManager entityManager = JPAUtil.getEntityManager();
		EntityTransaction transaction = entityManager.getTransaction();
		transaction.begin();

		Customer customer = entityManager.find(Customer.class, 1L);
		customer.setCustSource("電視廣告");

		Set<LinkMan> linkMans = customer.getLinkMans();
		for (LinkMan linkMan : linkMans) {
			linkMan.setLkmMobile("15633029014");
		}

		entityManager.persist(customer);

		transaction.commit();
		entityManager.close();
	}

	/**
	 * 運行之前,修改hibernate.hbm2ddl.auto=update
	 * 修改客戶、修改聯系人,保存聯系人級聯保存客戶
	 */
	@Test
	public void test6() {
		EntityManager entityManager = JPAUtil.getEntityManager();
		EntityTransaction transaction = entityManager.getTransaction();
		transaction.begin();

		LinkMan linkMan = entityManager.find(LinkMan.class, 1L);
		linkMan.setLkmMobile("110");

		Customer customer = linkMan.getCustomer();
		customer.setCustMobile("110");

		entityManager.persist(linkMan);

		transaction.commit();
		entityManager.close();
	}

	/**
	 * 運行之前,修改hibernate.hbm2ddl.auto=update
	 * 洗掉客戶級聯洗掉聯系人
	 */
	@Test
	public void test7() {
		EntityManager entityManager = JPAUtil.getEntityManager();
		EntityTransaction transaction = entityManager.getTransaction();
		transaction.begin();

		Customer customer = entityManager.find(Customer.class, 1L);
		entityManager.remove(customer);

		transaction.commit();
		entityManager.close();
	}

	/**
	 * 運行之前,修改hibernate.hbm2ddl.auto=update
	 * 洗掉聯系人級聯洗掉客戶
	 */
	@Test
	public void test8() {
		EntityManager entityManager = JPAUtil.getEntityManager();
		EntityTransaction transaction = entityManager.getTransaction();
		transaction.begin();

		LinkMan linkMan = entityManager.find(LinkMan.class, 3L);
		entityManager.remove(linkMan);

		transaction.commit();
		entityManager.close();
	}

}

3.2、多對多關聯

image-20200806230944798

sys_user(用戶表)

CREATE TABLE `sys_user` (
  `user_id` bigint(32) NOT NULL AUTO_INCREMENT COMMENT '用戶id',
  `user_code` varchar(32) DEFAULT NULL COMMENT '用戶賬號',
  `user_name` varchar(64) DEFAULT NULL COMMENT '用戶名稱',
  `user_password` varchar(32) DEFAULT NULL COMMENT '用戶密碼',
  `user_state` char(1) DEFAULT NULL COMMENT '用戶狀態',
  PRIMARY KEY (`user_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

sys_role(角色表)

CREATE TABLE `sys_role` (
  `role_id` bigint(32) NOT NULL AUTO_INCREMENT COMMENT '角色id',
  `role_name` varchar(32) DEFAULT NULL COMMENT '角色名稱',
  `role_memo` varchar(128) DEFAULT NULL COMMENT '角色備注',
  PRIMARY KEY (`role_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

sys_user_role(中間表)

CREATE TABLE `sys_user_role` (
  `role_id` bigint(32) NOT NULL COMMENT '角色id',
  `user_id` bigint(32) NOT NULL COMMENT '用戶id',
  PRIMARY KEY (`role_id`,`user_id`),
  KEY `FK_user_role_user_id` (`user_id`),
  CONSTRAINT `FK_user_role_role_id` FOREIGN KEY (`role_id`) REFERENCES `sys_role` (`role_id`) ON DELETE NO ACTION ON UPDATE NO ACTION,
  CONSTRAINT `FK_user_role_user_id` FOREIGN KEY (`user_id`) REFERENCES `sys_user` (`user_id`) ON DELETE NO ACTION ON UPDATE NO ACTION
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

3.2.1、創建物體

User.java(全路徑:/hibernate_jpa/src/com/caochenlei/hibernate/jpa/User.java)

package com.caochenlei.hibernate.jpa;

import java.util.HashSet;
import java.util.Set;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.ManyToMany;
import javax.persistence.Table;

@Entity
@Table(name = "sys_user")
public class User {

	@Id
	@GeneratedValue(strategy = GenerationType.IDENTITY)
	@Column(name = "user_id")
	private Long userId;

	@Column(name = "user_code")
	private String userCode;

	@Column(name = "user_name")
	private String userName;

	@Column(name = "user_password")
	private String userPassword;

	@Column(name = "user_state")
	private String userState;

	public Long getUserId() {
		return userId;
	}

	public void setUserId(Long userId) {
		this.userId = userId;
	}

	public String getUserCode() {
		return userCode;
	}

	public void setUserCode(String userCode) {
		this.userCode = userCode;
	}

	public String getUserName() {
		return userName;
	}

	public void setUserName(String userName) {
		this.userName = userName;
	}

	public String getUserPassword() {
		return userPassword;
	}

	public void setUserPassword(String userPassword) {
		this.userPassword = userPassword;
	}

	public String getUserState() {
		return userState;
	}

	public void setUserState(String userState) {
		this.userState = userState;
	}

	@Override
	public String toString() {
		return "User [userId=" + userId + ", userCode=" + userCode + ", userName=" + userName + ", userPassword=" + userPassword + ", userState=" + userState + "]";
	}

	/**
	 * 多對多:另一方的集合物件
	 * @ManyToMany	:映射多對多
	 * 	* fetch		:抓取策略
	 * 		FetchType.LAZY		:延遲加載(默認)
	 * 		FetchType.EAGER		:迫切查詢(多表連接查詢)
	 * 	* cascade	:級聯操作
	 * 		CascadeType.PERSIST	:級聯保存
	 * 		CascadeType.MERGE	:級聯更新
	 * 		CascadeType.REMOVE	:級聯洗掉
	 * 		CascadeType.ALL		:全部支持
	 * @JoinTable	:用于對應中間表的設定
	 * 	* name				:中間表名稱
	 * 	* joinColumns		:設定中間表與本表關聯的外鍵
	 * 	* inverseJoinColumns:設定中間表與關聯表對應的外鍵
	 */
	@ManyToMany(fetch = FetchType.EAGER, cascade = CascadeType.ALL)
	@JoinTable(name = "sys_user_role", joinColumns = @JoinColumn(name = "user_id"), inverseJoinColumns = @JoinColumn(name = "role_id"))
	private Set<Role> roles = new HashSet<Role>();

	public Set<Role> getRoles() {
		return roles;
	}

	public void setRoles(Set<Role> roles) {
		this.roles = roles;
	}

}

Role.java(全路徑:/hibernate_jpa/src/com/caochenlei/hibernate/jpa/Role.java)

package com.caochenlei.hibernate.jpa;

import java.util.HashSet;
import java.util.Set;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.ManyToMany;
import javax.persistence.Table;

@Entity
@Table(name = "sys_role")
public class Role {

	@Id
	@GeneratedValue(strategy = GenerationType.IDENTITY)
	@Column(name = "role_id")
	private Long roleId;

	@Column(name = "role_name")
	private String roleName;

	@Column(name = "role_memo")
	private String roleMemo;

	public Long getRoleId() {
		return roleId;
	}

	public void setRoleId(Long roleId) {
		this.roleId = roleId;
	}

	public String getRoleName() {
		return roleName;
	}

	public void setRoleName(String roleName) {
		this.roleName = roleName;
	}

	public String getRoleMemo() {
		return roleMemo;
	}

	public void setRoleMemo(String roleMemo) {
		this.roleMemo = roleMemo;
	}

	@Override
	public String toString() {
		return "Role [roleId=" + roleId + ", roleName=" + roleName + ", roleMemo=" + roleMemo + "]";
	}

	/**
	 * 多對多:另一方的集合物件
	 * @ManyToMany	:映射多對多
	 * 	* fetch		:抓取策略
	 * 		FetchType.LAZY		:延遲加載(默認)
	 * 		FetchType.EAGER		:迫切查詢(多表連接查詢)
	 * 	* cascade	:級聯操作
	 * 		CascadeType.PERSIST	:級聯保存
	 * 		CascadeType.MERGE	:級聯更新
	 * 		CascadeType.REMOVE	:級聯洗掉
	 * 		CascadeType.ALL		:全部支持
	 *  * mappedBy	:放棄外鍵維護
	 */
	@ManyToMany(fetch = FetchType.EAGER, cascade = CascadeType.ALL, mappedBy = "roles")
	private Set<User> users = new HashSet<User>();

	public Set<User> getUsers() {
		return users;
	}

	public void setUsers(Set<User> users) {
		this.users = users;
	}

}

3.2.2、測驗代碼

ManyToManyTest.java(全路徑:/hibernate_jpa/src/com/caochenlei/hibernate/jpa/ManyToManyTest.java)

package com.caochenlei.hibernate.jpa;

import java.util.Set;

import javax.persistence.EntityManager;
import javax.persistence.EntityTransaction;

import org.junit.Test;

public class ManyToManyTest {

	/**
	 * 運行之前,修改hibernate.hbm2ddl.auto=create
	 * 保存用戶級聯保存角色
	 */
	@Test
	public void test1() {
		EntityManager entityManager = JPAUtil.getEntityManager();
		EntityTransaction transaction = entityManager.getTransaction();
		transaction.begin();

		// 創建兩個用戶
		User user1 = new User();
		user1.setUserName("曹晨磊");
		User user2 = new User();
		user2.setUserName("曹晨旭");

		// 創建三個角色
		Role role1 = new Role();
		role1.setRoleName("呂布");
		Role role2 = new Role();
		role2.setRoleName("東皇");
		Role role3 = new Role();
		role3.setRoleName("趙云");

		user1.getRoles().add(role1);
		user1.getRoles().add(role2);
		user2.getRoles().add(role3);
		role1.getUsers().add(user1);
		role2.getUsers().add(user1);
		role3.getUsers().add(user2);

		entityManager.persist(user1);
		entityManager.persist(user2);

		transaction.commit();
		entityManager.close();
	}

	/**
	 * 運行之前,修改hibernate.hbm2ddl.auto=create
	 * 保存角色級聯保存用戶
	 */
	@Test
	public void test2() {
		EntityManager entityManager = JPAUtil.getEntityManager();
		EntityTransaction transaction = entityManager.getTransaction();
		transaction.begin();

		// 創建兩個用戶
		User user1 = new User();
		user1.setUserName("曹晨磊");
		User user2 = new User();
		user2.setUserName("曹晨旭");

		// 創建三個角色
		Role role1 = new Role();
		role1.setRoleName("呂布");
		Role role2 = new Role();
		role2.setRoleName("東皇");
		Role role3 = new Role();
		role3.setRoleName("趙云");

		user1.getRoles().add(role1);
		user1.getRoles().add(role2);
		user2.getRoles().add(role3);
		role1.getUsers().add(user1);
		role2.getUsers().add(user1);
		role3.getUsers().add(user2);

		entityManager.persist(role1);
		entityManager.persist(role2);
		entityManager.persist(role3);

		transaction.commit();
		entityManager.close();
	}

	/**
	 * 運行之前,修改hibernate.hbm2ddl.auto=update
	 * 查詢用戶級聯查詢角色
	 */
	@Test
	public void test3() {
		EntityManager entityManager = JPAUtil.getEntityManager();
		EntityTransaction transaction = entityManager.getTransaction();
		transaction.begin();

		User user = entityManager.find(User.class, 1L);
		System.out.println(user);

		Set<Role> roles = user.getRoles();
		for (Role role : roles) {
			System.out.println(role);
		}

		transaction.commit();
		entityManager.close();
	}

	/**
	 * 運行之前,修改hibernate.hbm2ddl.auto=update
	 * 查詢角色級聯查詢用戶
	 */
	@Test
	public void test4() {
		EntityManager entityManager = JPAUtil.getEntityManager();
		EntityTransaction transaction = entityManager.getTransaction();
		transaction.begin();

		Role role = entityManager.find(Role.class, 3L);
		System.out.println(role);

		Set<User> users = role.getUsers();
		for (User user : users) {
			System.out.println(user);
		}

		transaction.commit();
		entityManager.close();
	}

	/**
	 * 運行之前,修改hibernate.hbm2ddl.auto=update
	 * 修改用戶、修改角色,更新用戶級聯更新角色
	 */
	@Test
	public void test5() {
		EntityManager entityManager = JPAUtil.getEntityManager();
		EntityTransaction transaction = entityManager.getTransaction();
		transaction.begin();

		User user = entityManager.find(User.class, 1L);
		user.setUserPassword("123456");

		Set<Role> roles = user.getRoles();
		for (Role role : roles) {
			role.setRoleMemo("123456");
		}

		entityManager.merge(user);

		transaction.commit();
		entityManager.close();
	}

	/**
	 * 運行之前,修改hibernate.hbm2ddl.auto=update
	 * 修改用戶、修改角色,更新角色級聯更新用戶
	 */
	@Test
	public void test6() {
		EntityManager entityManager = JPAUtil.getEntityManager();
		EntityTransaction transaction = entityManager.getTransaction();
		transaction.begin();

		Role role = entityManager.find(Role.class, 3L);
		role.setRoleMemo("123456");

		Set<User> users = role.getUsers();
		for (User user : users) {
			user.setUserPassword("123456");
		}

		entityManager.merge(role);

		transaction.commit();
		entityManager.close();
	}

	/**
	 * 運行之前,修改hibernate.hbm2ddl.auto=update
	 * 洗掉用戶級聯洗掉角色
	 */
	@Test
	public void test7() {
		EntityManager entityManager = JPAUtil.getEntityManager();
		EntityTransaction transaction = entityManager.getTransaction();
		transaction.begin();

		User user = entityManager.find(User.class, 1L);
		entityManager.remove(user);

		transaction.commit();
		entityManager.close();
	}

	/**
	 * 運行之前,修改hibernate.hbm2ddl.auto=update
	 * 洗掉角色級聯洗掉用戶
	 */
	@Test
	public void test8() {
		EntityManager entityManager = JPAUtil.getEntityManager();
		EntityTransaction transaction = entityManager.getTransaction();
		transaction.begin();

		Role role = entityManager.find(Role.class, 3L);
		entityManager.remove(role);

		transaction.commit();
		entityManager.close();
	}

}

3.3、一對一關聯

image-20200808154248502

student_base_info(學生資訊基本表)

CREATE TABLE `student_base_info` (
  `stu_id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT '學生id',
  `stu_name` varchar(20) DEFAULT NULL COMMENT '學生姓名',
  `stu_sex` varchar(20) DEFAULT NULL COMMENT '學生性別',
  PRIMARY KEY (`stu_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

student_other_info(學生資訊拓展表)

CREATE TABLE `student_other_info` (
  `stu_id` bigint(20) NOT NULL COMMENT '學生id',
  `stu_img` varchar(255) DEFAULT NULL COMMENT '學生頭像',
  `stu_address` varchar(255) DEFAULT NULL COMMENT '學生地址',
  PRIMARY KEY (`stu_id`),
  CONSTRAINT `FK_stu_id` FOREIGN KEY (`stu_id`) REFERENCES `student_base_info` (`stu_id`) ON DELETE NO ACTION ON UPDATE NO ACTION
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

3.3.1、創建物體

StuBaseInfo.java(全路徑:/hibernate_jpa/src/com/caochenlei/hibernate/jpa/StuBaseInfo.java)

package com.caochenlei.hibernate.jpa;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.OneToOne;
import javax.persistence.Table;

@Entity
@Table(name = "student_base_info")
public class StuBaseInfo {

	@Id
	@GeneratedValue(strategy = GenerationType.IDENTITY)
	@Column(name = "stu_id")
	private Long stuId;

	@Column(name = "stu_name")
	private String stuName;

	@Column(name = "stu_sex")
	private String stuSex;

	public Long getStuId() {
		return stuId;
	}

	public void setStuId(Long stuId) {
		this.stuId = stuId;
	}

	public String getStuName() {
		return stuName;
	}

	public void setStuName(String stuName) {
		this.stuName = stuName;
	}

	public String getStuSex() {
		return stuSex;
	}

	public void setStuSex(String stuSex) {
		this.stuSex = stuSex;
	}

	@Override
	public String toString() {
		return "StuBaseInfo [stuId=" + stuId + ", stuName=" + stuName + ", stuSex=" + stuSex + "]";
	}

	/**
	 * 一對一:另一方的物件
	 * @OneToOne	:映射一對一
	 * 	* fetch		:抓取策略
	 * 		FetchType.LAZY		:延遲加載(默認)
	 * 		FetchType.EAGER		:迫切查詢(多表連接查詢)
	 * 	* cascade	:級聯操作
	 * 		CascadeType.PERSIST	:級聯保存
	 * 		CascadeType.MERGE	:級聯更新
	 * 		CascadeType.REMOVE	:級聯洗掉
	 * 		CascadeType.ALL		:全部支持
	 *  * mappedBy	:放棄外鍵維護
	 */
	@OneToOne(fetch = FetchType.EAGER, cascade = CascadeType.ALL, mappedBy = "stuBaseInfo")
	private StuOtherInfo stuOtherInfo;

	public StuOtherInfo getStuOtherInfo() {
		return stuOtherInfo;
	}

	public void setStuOtherInfo(StuOtherInfo stuOtherInfo) {
		this.stuOtherInfo = stuOtherInfo;
	}

}

StuOtherInfo.java(全路徑:/hibernate_jpa/src/com/caochenlei/hibernate/jpa/StuOtherInfo.java)

package com.caochenlei.hibernate.jpa;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.OneToOne;
import javax.persistence.Table;

@Entity
@Table(name = "student_other_info")
public class StuOtherInfo {

	@Id
	@GeneratedValue(strategy = GenerationType.IDENTITY)
	@Column(name = "stu_id")
	private Long stuId;

	@Column(name = "stu_img")
	private String stuImg;

	@Column(name = "stu_address")
	private String stuAddress;

	public Long getStuId() {
		return stuId;
	}

	public void setStuId(Long stuId) {
		this.stuId = stuId;
	}

	public String getStuImg() {
		return stuImg;
	}

	public void setStuImg(String stuImg) {
		this.stuImg = stuImg;
	}

	public String getStuAddress() {
		return stuAddress;
	}

	public void setStuAddress(String stuAddress) {
		this.stuAddress = stuAddress;
	}

	@Override
	public String toString() {
		return "StuOtherInfo [stuId=" + stuId + ", stuImg=" + stuImg + ", stuAddress=" + stuAddress + "]";
	}

	/**
	 * 一對一:另一方的物件
	 * @OneToOne	:映射一對一
	 * 	* fetch		:抓取策略
	 * 		FetchType.LAZY		:延遲加載(默認)
	 * 		FetchType.EAGER		:迫切查詢(多表連接查詢)
	 * 	* cascade	:級聯操作
	 * 		CascadeType.PERSIST	:級聯保存
	 * 		CascadeType.MERGE	:級聯更新
	 * 		CascadeType.REMOVE	:級聯洗掉
	 * 		CascadeType.ALL		:全部支持
	 * @JoinColumn	:設定兩張表之間外鍵列
	 * 		name				;外鍵的名稱
	 */
	@OneToOne(fetch = FetchType.EAGER, cascade = CascadeType.ALL)
	@JoinColumn(name = "stu_id")
	private StuBaseInfo stuBaseInfo ;

	public StuBaseInfo getStuBaseInfo() {
		return stuBaseInfo;
	}

	public void setStuBaseInfo(StuBaseInfo stuBaseInfo) {
		this.stuBaseInfo = stuBaseInfo;
	}

}

3.3.2、測驗代碼

OneToOneTest.java(全路徑:/hibernate_jpa/src/com/caochenlei/hibernate/jpa/OneToOneTest.java)

package com.caochenlei.hibernate.jpa;

import javax.persistence.EntityManager;
import javax.persistence.EntityTransaction;

import org.junit.Test;

public class OneToOneTest {

	/**
	 * 運行之前,修改hibernate.hbm2ddl.auto=create
	 * 保存學生基本資訊級聯保存學生拓展資訊
	 */
	@Test
	public void test1() {
		EntityManager entityManager = JPAUtil.getEntityManager();
		EntityTransaction transaction = entityManager.getTransaction();
		transaction.begin();

		// 創建兩個學生基本資訊
		StuBaseInfo stuBaseInfo1 = new StuBaseInfo();
		stuBaseInfo1.setStuName("張三");
		StuBaseInfo stuBaseInfo2 = new StuBaseInfo();
		stuBaseInfo2.setStuName("李四");

		// 創建兩個學生拓展資訊
		StuOtherInfo stuOtherInfo1 = new StuOtherInfo();
		stuOtherInfo1.setStuImg("http:img.caochenlei.com/001.png");
		StuOtherInfo stuOtherInfo2 = new StuOtherInfo();
		stuOtherInfo2.setStuImg("http:img.caochenlei.com/002.png");

		stuBaseInfo1.setStuOtherInfo(stuOtherInfo1);
		stuBaseInfo2.setStuOtherInfo(stuOtherInfo2);
		stuOtherInfo1.setStuBaseInfo(stuBaseInfo1);
		stuOtherInfo2.setStuBaseInfo(stuBaseInfo2);

		entityManager.persist(stuBaseInfo1);
		entityManager.persist(stuBaseInfo2);

		transaction.commit();
		entityManager.close();
	}

	/**
	 * 運行之前,修改hibernate.hbm2ddl.auto=create
	 * 保存學生拓展資訊級聯保存學生基本資訊
	 */
	@Test
	public void test2() {
		EntityManager entityManager = JPAUtil.getEntityManager();
		EntityTransaction transaction = entityManager.getTransaction();
		transaction.begin();

		// 創建兩個學生基本資訊
		StuBaseInfo stuBaseInfo1 = new StuBaseInfo();
		stuBaseInfo1.setStuName("張三");
		StuBaseInfo stuBaseInfo2 = new StuBaseInfo();
		stuBaseInfo2.setStuName("李四");

		// 創建兩個學生拓展資訊
		StuOtherInfo stuOtherInfo1 = new StuOtherInfo();
		stuOtherInfo1.setStuImg("http:img.caochenlei.com/001.png");
		StuOtherInfo stuOtherInfo2 = new StuOtherInfo();
		stuOtherInfo2.setStuImg("http:img.caochenlei.com/002.png");

		stuBaseInfo1.setStuOtherInfo(stuOtherInfo1);
		stuBaseInfo2.setStuOtherInfo(stuOtherInfo2);
		stuOtherInfo1.setStuBaseInfo(stuBaseInfo1);
		stuOtherInfo2.setStuBaseInfo(stuBaseInfo2);

		entityManager.persist(stuOtherInfo1);
		entityManager.persist(stuOtherInfo2);

		transaction.commit();
		entityManager.close();
	}

	/**
	 * 運行之前,修改hibernate.hbm2ddl.auto=update
	 * 查詢學生基本資訊級聯查詢學生拓展資訊
	 */
	@Test
	public void test3() {
		EntityManager entityManager = JPAUtil.getEntityManager();
		EntityTransaction transaction = entityManager.getTransaction();
		transaction.begin();

		StuBaseInfo stuBaseInfo = entityManager.find(StuBaseInfo.class, 1L);
		System.out.println(stuBaseInfo);
		StuOtherInfo stuOtherInfo = stuBaseInfo.getStuOtherInfo();
		System.out.println(stuOtherInfo);

		transaction.commit();
		entityManager.close();
	}

	/**
	 * 運行之前,修改hibernate.hbm2ddl.auto=update
	 * 查詢學生拓展資訊級聯查詢學生基本資訊
	 */
	@Test
	public void test4() {
		EntityManager entityManager = JPAUtil.getEntityManager();
		EntityTransaction transaction = entityManager.getTransaction();
		transaction.begin();

		StuOtherInfo stuOtherInfo = entityManager.find(StuOtherInfo.class, 1L);
		System.out.println(stuOtherInfo);
		StuBaseInfo stuBaseInfo = stuOtherInfo.getStuBaseInfo();
		System.out.println(stuBaseInfo);

		transaction.commit();
		entityManager.close();
	}

	/**
	 * 運行之前,修改hibernate.hbm2ddl.auto=update
	 * 更新學生基本資訊級聯更新學生拓展資訊
	 */
	@Test
	public void test5() {
		EntityManager entityManager = JPAUtil.getEntityManager();
		EntityTransaction transaction = entityManager.getTransaction();
		transaction.begin();

		StuBaseInfo stuBaseInfo = entityManager.find(StuBaseInfo.class, 1L);
		stuBaseInfo.setStuSex("男");
		StuOtherInfo stuOtherInfo = stuBaseInfo.getStuOtherInfo();
		stuOtherInfo.setStuAddress("河北省");
		entityManager.merge(stuBaseInfo);

		transaction.commit();
		entityManager.close();
	}

	/**
	 * 運行之前,修改hibernate.hbm2ddl.auto=update
	 * 更新學生拓展資訊級聯更新學生基本資訊
	 */
	@Test
	public void test6() {
		EntityManager entityManager = JPAUtil.getEntityManager();
		EntityTransaction transaction = entityManager.getTransaction();
		transaction.begin();

		StuOtherInfo stuOtherInfo = entityManager.find(StuOtherInfo.class, 2L);
		stuOtherInfo.setStuAddress("河南省");
		StuBaseInfo stuBaseInfo = stuOtherInfo.getStuBaseInfo();
		stuBaseInfo.setStuSex("女");
		entityManager.merge(stuOtherInfo);

		transaction.commit();
		entityManager.close();
	}

	/**
	 * 運行之前,修改hibernate.hbm2ddl.auto=update
	 * 洗掉學生基本資訊級聯洗掉學生拓展資訊
	 */
	@Test
	public void test7() {
		EntityManager entityManager = JPAUtil.getEntityManager();
		EntityTransaction transaction = entityManager.getTransaction();
		transaction.begin();

		StuBaseInfo stuBaseInfo = entityManager.find(StuBaseInfo.class, 1L);
		entityManager.remove(stuBaseInfo);

		transaction.commit();
		entityManager.close();
	}

	/**
	 * 運行之前,修改hibernate.hbm2ddl.auto=update
	 * 洗掉學生拓展資訊級聯洗掉學生基本資訊
	 */
	@Test
	public void test8() {
		EntityManager entityManager = JPAUtil.getEntityManager();
		EntityTransaction transaction = entityManager.getTransaction();
		transaction.begin();

		StuOtherInfo stuOtherInfo = entityManager.find(StuOtherInfo.class, 2L);
		entityManager.remove(stuOtherInfo);

		transaction.commit();
		entityManager.close();
	}

}

第四章 Hibernate5 JPA的JPQL查詢

初始化資料,運行init方法:

InitQueryData.java(全路徑:/hibernate_jpa/src/com/caochenlei/hibernate/jpa/InitQueryData.java)

package com.caochenlei.hibernate.jpa;

import javax.persistence.EntityManager;
import javax.persistence.EntityTransaction;

import org.junit.Test;

public class InitQueryData {

	/**
	 * 執行前:修改hibernate.hbm2ddl.auto=create
	 * 執行此方法
	 * 執行后:修改hibernate.hbm2ddl.auto=update
	 */
	@Test
	public void init() {
		EntityManager entityManager = JPAUtil.getEntityManager();
		EntityTransaction transaction = entityManager.getTransaction();
		transaction.begin();

		// 創建一個客戶
		Customer customer1 = new Customer();
		customer1.setCustName("張三");
		customer1.setCustSource("電視廣告");
		// 創建十個聯系人
		for (int i = 1; i <= 10; i++) {
			LinkMan linkMan = new LinkMan();
			linkMan.setLkmName("張三的聯系人" + i);
			linkMan.setCustomer(customer1);
			customer1.getLinkMans().add(linkMan);
			entityManager.persist(linkMan);
		}
		entityManager.persist(customer1);

		// 創建一個客戶
		Customer customer2 = new Customer();
		customer2.setCustName("李四");
		customer2.setCustSource("網路論壇");
		// 創建十個聯系人
		for (int i = 1; i <= 10; i++) {
			LinkMan linkMan = new LinkMan();
			linkMan.setLkmName("李四的聯系人" + i);
			linkMan.setCustomer(customer2);
			customer2.getLinkMans().add(linkMan);
			entityManager.persist(linkMan);
		}
		entityManager.persist(customer2);

		// 創建一個客戶
		Customer customer3 = new Customer();
		customer3.setCustName("王五");
		customer3.setCustSource("街邊告示");
		// 創建十個聯系人
		for (int i = 1; i <= 10; i++) {
			LinkMan linkMan = new LinkMan();
			linkMan.setLkmName("王五的聯系人" + i);
			linkMan.setCustomer(customer3);
			customer3.getLinkMans().add(linkMan);
			entityManager.persist(linkMan);
		}
		entityManager.persist(customer3);

		// 創建一個客戶
		Customer customer4 = new Customer();
		customer4.setCustName("王五");
		customer4.setCustSource("電視廣告");
		entityManager.persist(customer4);

		transaction.commit();
		entityManager.close();
	}

}

以下的方法,均在下邊檔案進行測驗:

JPQLTest.java(全路徑:/hibernate_jpa/src/com/caochenlei/hibernate/jpa/JPQLTest.java)

4.1、簡單查詢

@Test
public void test1() {
	EntityManager entityManager = JPAUtil.getEntityManager();
	EntityTransaction transaction = entityManager.getTransaction();
	transaction.begin();

	// 查詢所有客戶
	Query query = entityManager.createQuery("from Customer");
	List<Customer> list = query.getResultList();
	for (Customer customer : list) {
		System.out.println(customer);
	}
	System.err.println("--------------------------------------------------");

	transaction.commit();
	entityManager.close();
}

4.2、別名查詢

@Test
public void test2() {
	EntityManager entityManager = JPAUtil.getEntityManager();
	EntityTransaction transaction = entityManager.getTransaction();
	transaction.begin();

	// 查詢所有客戶
	Query query1 = entityManager.createQuery("from Customer c");
	List<Customer> list1 = query1.getResultList();
	for (Customer customer : list1) {
		System.out.println(customer);
	}
	System.err.println("--------------------------------------------------");

	// 查詢所有客戶
	Query query2 = entityManager.createQuery("select c from Customer c");
	List<Customer> list2 = query2.getResultList();
	for (Customer customer : list2) {
		System.out.println(customer);
	}
	System.err.println("--------------------------------------------------");

	transaction.commit();
	entityManager.close();
}

4.3、排序查詢

@Test
public void test3() {
	EntityManager entityManager = JPAUtil.getEntityManager();
	EntityTransaction transaction = entityManager.getTransaction();
	transaction.begin();

	// 采用鏈式呼叫,默認情況(升序)
	List<Customer> list1 = entityManager.createQuery("from Customer order by cust_id").getResultList();
	for (Customer customer : list1) {
		System.out.println(customer);
	}
	System.err.println("--------------------------------------------------");

	// 采用鏈式呼叫,升序情況
	List<Customer> list2 = entityManager.createQuery("from Customer order by cust_id asc").getResultList();
	for (Customer customer : list2) {
		System.out.println(customer);
	}
	System.err.println("--------------------------------------------------");

	// 采用鏈式呼叫,降序情況
	List<Customer> list3 = entityManager.createQuery("from Customer order by cust_id desc").getResultList();
	for (Customer customer : list3) {
		System.out.println(customer);
	}
	System.err.println("--------------------------------------------------");

	transaction.commit();
	entityManager.close();
}

4.4、條件查詢

@Test
public void test4() {
	EntityManager entityManager = JPAUtil.getEntityManager();
	EntityTransaction transaction = entityManager.getTransaction();
	transaction.begin();

	// 條件查詢:按引數位置系結
	Query query1 = entityManager.createQuery("from Customer where cust_source = ? and cust_name like ?");
	query1.setParameter(1, "電視廣告");
	query1.setParameter(2, "王%");
	List<Customer> list1 = query1.getResultList();
	for (Customer customer : list1) {
		System.out.println(customer);
	}
	System.err.println("--------------------------------------------------");

	// 條件查詢:按引數名稱系結
	Query query2 = entityManager.createQuery("from Customer where cust_source = :aaa and cust_name like :bbb");
	query2.setParameter("aaa", "電視廣告");
	query2.setParameter("bbb", "王%");
	List<Customer> list2 = query2.getResultList();
	for (Customer customer : list2) {
		System.out.println(customer);
	}
	System.err.println("--------------------------------------------------");

	transaction.commit();
	entityManager.close();
}

4.5、投影查詢

@Test
public void test5() {
	EntityManager entityManager = JPAUtil.getEntityManager();
	EntityTransaction transaction = entityManager.getTransaction();
	transaction.begin();

	// 查詢所有客戶名稱:單個欄位查詢
	Query query1 = entityManager.createQuery("select c.custName from Customer c");
	List<Object> list1 = query1.getResultList();
	for (Object cust_name : list1) {
		System.out.println(cust_name);
	}
	System.err.println("--------------------------------------------------");

	// 查詢所有客戶名稱、客戶來源:多個欄位查詢,封裝到陣列中
	Query query2 = entityManager.createQuery("select c.custName,c.custSource from Customer c");
	List<Object[]> list2 = query2.getResultList();
	for (Object[] objects : list2) {
		System.out.println(Arrays.toString(objects));
	}
	System.err.println("--------------------------------------------------");

	// 查詢所有客戶名稱、客戶來源:多個欄位查詢,封裝到物件中
	// 請在Customer.java添加以下兩個構造方法,否則會執行失敗
	// public Customer()
	// public Customer(String custName, String custSource)
	Query query3 = entityManager.createQuery("select new Customer(c.custName,c.custSource) from Customer c");
	List<Customer> list3 = query3.getResultList();
	for (Customer customer : list3) {
		System.out.println(customer);
	}
	System.err.println("--------------------------------------------------");

	transaction.commit();
	entityManager.close();
}

4.6、分頁查詢

@Test
public void test6() {
	EntityManager entityManager = JPAUtil.getEntityManager();
	EntityTransaction transaction = entityManager.getTransaction();
	transaction.begin();

	// 分頁查詢
	Query query = entityManager.createQuery("from LinkMan");
	query.setFirstResult(0);
	query.setMaxResults(10);
	List<LinkMan> list = query.getResultList();
	for (LinkMan linkMan : list) {
		System.out.println(linkMan);
	}
	System.err.println("--------------------------------------------------");

	transaction.commit();
	entityManager.close();
}

4.7、分組查詢

@Test
public void test7() {
	EntityManager entityManager = JPAUtil.getEntityManager();
	EntityTransaction transaction = entityManager.getTransaction();
	transaction.begin();

	// 聚合函式:count(),max(),min(),avg(),sum()
	Object object = entityManager.createQuery("select count(*) from Customer").getSingleResult();
	System.out.println(object);
	System.err.println("--------------------------------------------------");

	// 分組統計:
	List<Object[]> list = entityManager.createQuery("select custSource,count(*) from Customer group by cust_source").getResultList();
	for (Object[] objects : list) {
		System.out.println(Arrays.toString(objects));
	}
	System.err.println("--------------------------------------------------");

	transaction.commit();
	entityManager.close();
}

4.8、多表查詢

@Test
public void test8() {
	EntityManager entityManager = JPAUtil.getEntityManager();
	EntityTransaction transaction = entityManager.getTransaction();
	transaction.begin();

	// 內連接
	List<Object[]> list1 = entityManager.createQuery("from Customer c inner join c.linkMans").getResultList();
	for (Object[] objects : list1) {
		System.out.println(Arrays.toString(objects));
	}
	System.err.println("--------------------------------------------------");

	// 迫切內連接(hibernate獨有,將另一個物件的資料封裝到該物件中)
	List<Customer> list2 = entityManager.createQuery("select distinct c from Customer c inner join fetch c.linkMans").getResultList();
	for (Customer customer : list2) {
		System.out.println(customer);
	}
	System.err.println("--------------------------------------------------");

	// 左外連接
	List<Object[]> list3 = entityManager.createQuery("from Customer c left outer join c.linkMans").getResultList();
	for (Object[] objects : list3) {
		System.out.println(Arrays.toString(objects));
	}
	System.err.println("--------------------------------------------------");

	// 迫切左外連接(hibernate獨有,將另一個物件的資料封裝到該物件中)
	List<Customer> list4 = entityManager.createQuery("select distinct c from Customer c left outer join fetch c.linkMans").getResultList();
	for (Customer customer : list4) {
		System.out.println(customer);
	}
	System.err.println("--------------------------------------------------");

	// 右外連接
	List<Object[]> list5 = entityManager.createQuery("from Customer c right outer join c.linkMans").getResultList();
	for (Object[] objects : list5) {
		System.out.println(Arrays.toString(objects));
	}
	System.err.println("--------------------------------------------------");

	transaction.commit();
	entityManager.close();
}

轉載請註明出處,本文鏈接:https://www.uj5u.com/shujuku/220404.html

標籤:其他

上一篇:資料庫命令規范

下一篇:?LeetCode刷題實戰96:不同的二叉搜索樹

標籤雲
其他(157675) Python(38076) JavaScript(25376) Java(17977) C(15215) 區塊鏈(8255) C#(7972) AI(7469) 爪哇(7425) MySQL(7132) html(6777) 基礎類(6313) sql(6102) 熊猫(6058) PHP(5869) 数组(5741) R(5409) Linux(5327) 反应(5209) 腳本語言(PerlPython)(5129) 非技術區(4971) Android(4554) 数据框(4311) css(4259) 节点.js(4032) C語言(3288) json(3245) 列表(3129) 扑(3119) C++語言(3117) 安卓(2998) 打字稿(2995) VBA(2789) Java相關(2746) 疑難問題(2699) 细绳(2522) 單片機工控(2479) iOS(2429) ASP.NET(2402) MongoDB(2323) 麻木的(2285) 正则表达式(2254) 字典(2211) 循环(2198) 迅速(2185) 擅长(2169) 镖(2155) 功能(1967) .NET技术(1958) Web開發(1951) python-3.x(1918) HtmlCss(1915) 弹簧靴(1913) C++(1909) xml(1889) PostgreSQL(1872) .NETCore(1853) 谷歌表格(1846) Unity3D(1843) for循环(1842)

熱門瀏覽
  • GPU虛擬機創建時間深度優化

    **?桔妹導讀:**GPU虛擬機實體創建速度慢是公有云面臨的普遍問題,由于通常情況下創建虛擬機屬于低頻操作而未引起業界的重視,實際生產中還是存在對GPU實體創建時間有苛刻要求的業務場景。本文將介紹滴滴云在解決該問題時的思路、方法、并展示最終的優化成果。 從公有云服務商那里購買過虛擬主機的資深用戶,一 ......

    uj5u.com 2020-09-10 06:09:13 more
  • 可編程網卡芯片在滴滴云網路的應用實踐

    **?桔妹導讀:**隨著云規模不斷擴大以及業務層面對延遲、帶寬的要求越來越高,采用DPDK 加速網路報文處理的方式在橫向縱向擴展都出現了局限性。可編程芯片成為業界熱點。本文主要講述了可編程網卡芯片在滴滴云網路中的應用實踐,遇到的問題、帶來的收益以及開源社區貢獻。 #1. 資料中心面臨的問題 隨著滴滴 ......

    uj5u.com 2020-09-10 06:10:21 more
  • 滴滴資料通道服務演進之路

    **?桔妹導讀:**滴滴資料通道引擎承載著全公司的資料同步,為下游實時和離線場景提供了必不可少的源資料。隨著任務量的不斷增加,資料通道的整體架構也隨之發生改變。本文介紹了滴滴資料通道的發展歷程,遇到的問題以及今后的規劃。 #1. 背景 資料,對于任何一家互聯網公司來說都是非常重要的資產,公司的大資料 ......

    uj5u.com 2020-09-10 06:11:05 more
  • 滴滴AI Labs斬獲國際機器翻譯大賽中譯英方向世界第三

    **桔妹導讀:**深耕人工智能領域,致力于探索AI讓出行更美好的滴滴AI Labs再次斬獲國際大獎,這次獲獎的專案是什么呢?一起來看看詳細報道吧! 近日,由國際計算語言學協會ACL(The Association for Computational Linguistics)舉辦的世界最具影響力的機器 ......

    uj5u.com 2020-09-10 06:11:29 more
  • MPP (Massively Parallel Processing)大規模并行處理

    1、什么是mpp? MPP (Massively Parallel Processing),即大規模并行處理,在資料庫非共享集群中,每個節點都有獨立的磁盤存盤系統和記憶體系統,業務資料根據資料庫模型和應用特點劃分到各個節點上,每臺資料節點通過專用網路或者商業通用網路互相連接,彼此協同計算,作為整體提供 ......

    uj5u.com 2020-09-10 06:11:41 more
  • 滴滴資料倉庫指標體系建設實踐

    **桔妹導讀:**指標體系是什么?如何使用OSM模型和AARRR模型搭建指標體系?如何統一流程、規范化、工具化管理指標體系?本文會對建設的方法論結合滴滴資料指標體系建設實踐進行解答分析。 #1. 什么是指標體系 ##1.1 指標體系定義 指標體系是將零散單點的具有相互聯系的指標,系統化的組織起來,通 ......

    uj5u.com 2020-09-10 06:12:52 more
  • 單表千萬行資料庫 LIKE 搜索優化手記

    我們經常在資料庫中使用 LIKE 運算子來完成對資料的模糊搜索,LIKE 運算子用于在 WHERE 子句中搜索列中的指定模式。 如果需要查找客戶表中所有姓氏是“張”的資料,可以使用下面的 SQL 陳述句: SELECT * FROM Customer WHERE Name LIKE '張%' 如果需要 ......

    uj5u.com 2020-09-10 06:13:25 more
  • 滴滴Ceph分布式存盤系統優化之鎖優化

    **桔妹導讀:**Ceph是國際知名的開源分布式存盤系統,在工業界和學術界都有著重要的影響。Ceph的架構和演算法設計發表在國際系統領域頂級會議OSDI、SOSP、SC等上。Ceph社區得到Red Hat、SUSE、Intel等大公司的大力支持。Ceph是國際云計算領域應用最廣泛的開源分布式存盤系統, ......

    uj5u.com 2020-09-10 06:14:51 more
  • es~通過ElasticsearchTemplate進行聚合~嵌套聚合

    之前寫過《es~通過ElasticsearchTemplate進行聚合操作》的文章,這一次主要寫一個嵌套的聚合,例如先對sex集合,再對desc聚合,最后再對age求和,共三層嵌套。 Aggregations的部分特性類似于SQL語言中的group by,avg,sum等函式,Aggregation ......

    uj5u.com 2020-09-10 06:14:59 more
  • 爬蟲日志監控 -- Elastc Stack(ELK)部署

    傻瓜式部署,只需替換IP與用戶 導讀: 現ELK四大組件分別為:Elasticsearch(核心)、logstash(處理)、filebeat(采集)、kibana(可視化) 下載均在https://www.elastic.co/cn/downloads/下tar包,各組件版本最好一致,配合fdm會 ......

    uj5u.com 2020-09-10 06:15:05 more
最新发布
  • day02-2-商鋪查詢快取

    功能02-商鋪查詢快取 3.商鋪詳情快取查詢 3.1什么是快取? 快取就是資料交換的緩沖區(稱作Cache),是存盤資料的臨時地方,一般讀寫性能較高。 快取的作用: 降低后端負載 提高讀寫效率,降低回應時間 快取的成本: 資料一致性成本 代碼維護成本 運維成本 3.2需求說明 如下,當我們點擊商店詳 ......

    uj5u.com 2023-04-20 08:33:24 more
  • MySQL中binlog備份腳本分享

    關于MySQL的二進制日志(binlog),我們都知道二進制日志(binlog)非常重要,尤其當你需要point to point災難恢復的時侯,所以我們要對其進行備份。關于二進制日志(binlog)的備份,可以基于flush logs方式先切換binlog,然后拷貝&壓縮到到遠程服務器或本地服務器 ......

    uj5u.com 2023-04-20 08:28:06 more
  • day02-短信登錄

    功能實作02 2.功能01-短信登錄 2.1基于Session實作登錄 2.1.1思路分析 2.1.2代碼實作 2.1.2.1發送短信驗證碼 發送短信驗證碼: 發送驗證碼的介面為:http://127.0.0.1:8080/api/user/code?phone=xxxxx<手機號> 請求方式:PO ......

    uj5u.com 2023-04-20 08:27:27 more
  • 快取與資料庫雙寫一致性幾種策略分析

    本文將對幾種快取與資料庫保證資料一致性的使用方式進行分析。為保證高并發性能,以下分析場景不考慮執行的原子性及加鎖等強一致性要求的場景,僅追求最終一致性。 ......

    uj5u.com 2023-04-20 08:26:48 more
  • sql陳述句優化

    問題查找及措施 問題查找 需要找到具體的代碼,對其進行一對一優化,而非一直把關注點放在服務器和sql平臺 降低簡化每個事務中處理的問題,盡量不要讓一個事務拖太長的時間 例如檔案上傳時,應將檔案上傳這一步放在事務外面 微軟建議 4.啟動sql定時執行計劃 怎么啟動sqlserver代理服務-百度經驗 ......

    uj5u.com 2023-04-20 08:26:35 more
  • 云時代,MySQL到ClickHouse資料同步產品對比推薦

    ClickHouse 在執行分析查詢時的速度優勢很好的彌補了MySQL的不足,但是對于很多開發者和DBA來說,如何將MySQL穩定、高效、簡單的同步到 ClickHouse 卻很困難。本文對比了 NineData、MaterializeMySQL(ClickHouse自帶)、Bifrost 三款產品... ......

    uj5u.com 2023-04-20 08:26:29 more
  • sql陳述句優化

    問題查找及措施 問題查找 需要找到具體的代碼,對其進行一對一優化,而非一直把關注點放在服務器和sql平臺 降低簡化每個事務中處理的問題,盡量不要讓一個事務拖太長的時間 例如檔案上傳時,應將檔案上傳這一步放在事務外面 微軟建議 4.啟動sql定時執行計劃 怎么啟動sqlserver代理服務-百度經驗 ......

    uj5u.com 2023-04-20 08:25:13 more
  • Redis 報”OutOfDirectMemoryError“(堆外記憶體溢位)

    Redis 報錯“OutOfDirectMemoryError(堆外記憶體溢位) ”問題如下: 一、報錯資訊: 使用 Redis 的業務介面 ,產生 OutOfDirectMemoryError(堆外記憶體溢位),如圖: 格式化后的報錯資訊: { "timestamp": "2023-04-17 22: ......

    uj5u.com 2023-04-20 08:24:54 more
  • day02-2-商鋪查詢快取

    功能02-商鋪查詢快取 3.商鋪詳情快取查詢 3.1什么是快取? 快取就是資料交換的緩沖區(稱作Cache),是存盤資料的臨時地方,一般讀寫性能較高。 快取的作用: 降低后端負載 提高讀寫效率,降低回應時間 快取的成本: 資料一致性成本 代碼維護成本 運維成本 3.2需求說明 如下,當我們點擊商店詳 ......

    uj5u.com 2023-04-20 08:24:03 more
  • day02-短信登錄

    功能實作02 2.功能01-短信登錄 2.1基于Session實作登錄 2.1.1思路分析 2.1.2代碼實作 2.1.2.1發送短信驗證碼 發送短信驗證碼: 發送驗證碼的介面為:http://127.0.0.1:8080/api/user/code?phone=xxxxx<手機號> 請求方式:PO ......

    uj5u.com 2023-04-20 08:23:11 more