MyBatis:框架的搭建及測驗-有解無憂

1.開發環境

新建一個工程-配置jdk版本-配置maven

2.創建maven工程

修改打包方式為jar

匯入依賴：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.tinstu.mybatis</groupId>
    <artifactId>MyBatis_demo1</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>
    <dependencies>
        <!-- Mybatis核心 -->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.7</version>
        </dependency>
        <!-- junit測驗 -->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
        <!-- MySQL驅動 -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.3</version>
        </dependency>
    </dependencies>


</project>

3.創建MyBatis的核心組態檔 mybatis-config.xml

在resources下創建mybatis-config.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <!--設定連接資料庫的環境-->
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="https://www.cnblogs.com/tinstu/p/com.mysql.jdbc.Driver"/>
                <property name="url" value="https://www.cnblogs.com/tinstu/p/jdbc:mysql://localhost:3306/MyBatis"/>
                <property name="username" value="https://www.cnblogs.com/tinstu/p/root"/>
                <property name="password" value="https://www.cnblogs.com/tinstu/p/123456"/>
            </dataSource>
        </environment>
    </environments>
    <!--引入映射檔案-->
    <mappers>
        <mapper resource="mappers/UserMapper.xml"/>
    </mappers>
</configuration>

4.創建mapper介面 UserMapper.java

MyBatis中的mapper介面相當于以前的dao，但是區別于，mapper僅僅是介面，我們不需要提供實作類

先在 mybatis-config.xml中配置好資料庫資訊，創建一個資料庫，創建物體類User.java

創建一個介面 UserMapper.java

package com.tinstu.mybatis.mapper;
public interface UserMapper {

  //添加用戶資訊
  int insertUser();
}

5.創建MyBatis的映射檔案 UserMapper.xml

MyBatis面向介面編程的兩個一致

1.映射檔案UserMapper.xml的 namespace和mapper介面UserMapper.java的全類名保持一致 <mapper namespace="com.tinstu.mybatis.mapper.UserMapper">
2.映射檔案中sql陳述句的id要和mapper介面中的方法名一致（此映射檔案中事務id=insertUser和上面介面中的方法名insertUser一樣）

表---物體類---mapper介面---映射檔案

mapper介面的全類名和映射檔案的命名空間（namespace）保持一致

- mapper介面中方法的方法名和映射檔案中撰寫SQL的標簽的id屬性保持一致

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.tinstu.mybatis.mapper.UserMapper">
    <!--int insertUser();-->
    <insert id="insertUser">
        insert into t_user values(null,'張三','123','[email protected]')
    </insert>
</mapper>

最后還要在組態檔mybatis-config.xml中引入映射檔案

<!--引入映射檔案--> 
<mappers> 
      <mapper resource="mappers/UserMapper.xml"/> 
</mappers>

6.測驗添加功能

創建一個測驗類

package com.tinstu.mybatis;
import com.tinstu.mybatis.mapper.UserMapper;

import org.apache.ibatis.io.Resources;

import org.apache.ibatis.session.SqlSession;

import org.apache.ibatis.session.SqlSessionFactory;

import org.apache.ibatis.session.SqlSessionFactoryBuilder;

import org.junit.Test;
import java.io.IOException;

import java.io.InputStream;
public class Mybatistest {

@Test

public void testmybatis() throws IOException{

//加載核心組態檔

InputStream is = Resources.getResourceAsStream("mybatis-config.xml");

//獲取SqlSessionFactoryBuilder

SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();

//獲取sqlSessionFactory

SqlSessionFactory sqlSessionFactory = sqlSessionFactoryBuilder.build(is);

//獲取SqlSession

SqlSession sqlSession = sqlSessionFactory.openSession();

//獲取mapper介面物件

UserMapper mapper = sqlSession.getMapper(UserMapper.class) ;

//測驗功能

int result = mapper.insertUser();

//提交事務

sqlSession.commit();
}

}

7.優化功能

1.SqlSession默認不自動提交事務，如需要自動提交事務，可以使用SqlSessionFactory.openSession(true);

        //獲取SqlSession(加入true)
        SqlSession sqlSession = sqlSessionFactory.openSession(true);
        //獲取mapper介面物件
        UserMapper mapper = sqlSession.getMapper(UserMapper.class) ;
        //測驗功能
        int result = mapper.insertUser();
        //提交事務（刪掉）
       // sqlSession.commit();

2.加入log4j日志功能

（1）加入依賴

<!-- log4j日志 -->
<dependency>
   <groupId>log4j</groupId>
   <artifactId>log4j</artifactId>
   <version>1.2.17</version>
</dependency>

（2）加入log4j的組態檔

log4j的組態檔名為log4j.xml，存放的位置是src/main/resources目錄下
日志的級別：FATAL(致命)>ERROR(錯誤)>WARN(警告)>INFO(資訊)>DEBUG(除錯) 從左到右列印的內容越來越詳細

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
<log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">
    <appender name="STDOUT" >
        <param name="Encoding" value="https://www.cnblogs.com/tinstu/p/UTF-8" />
        <layout >
			<param name="ConversionPattern" value="https://www.cnblogs.com/tinstu/p/%-5p %d{MM-dd HH:mm:ss,SSS} %m (%F:%L) /n" />
        </layout>
    </appender>
    <logger name="java.sql">
        <level value="https://www.cnblogs.com/tinstu/p/debug" />
    </logger>
    <logger name="org.apache.ibatis">
        <level value="https://www.cnblogs.com/tinstu/p/info" />
    </logger>
    <root>
        <level value="https://www.cnblogs.com/tinstu/p/debug" />
        <appender-ref ref="STDOUT" />
    </root>
</log4j:configuration>

8.測驗洗掉修改功能

（1）修改

UserMapper.xml中加入

    <!--void updateUser();-->
    <update id="updateUser">
        update user set username = '張三55' where id = 3 ;
    </update>

測驗類

   @Test
    public void testuodate() throws IOException{
        InputStream is = Resources.getResourceAsStream("mybatis-config.xml");
        SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();
        SqlSessionFactory sqlSessionFactory = sqlSessionFactoryBuilder.build(is);
        SqlSession sqlSession = sqlSessionFactory.openSession(true);
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        mapper.updateUser();
   }

洗掉：

    <!--void deleteUser();-->
    <delete id="deleteUser">
        delete from user where id = 5
    </delete>

9.測驗查詢功能

（1）根據id查詢

UserMapper.java中添加查詢方法

    //查詢功能
    User getUser();

UserMapper.xml中寫sql陳述句

    <!--void getUser();-->
    <!--
        查詢功能的標簽必須設定resultType或resultMap
        resultType：設定默認的映射關系
        resultMap:設定自定義的映射關系
    -->
    <select id="getUser" resultType="com.tinstu.mybatis.pojo.User">
        select * from user where  id=3
    </select>

測驗類：

   @Test
    public void testuodate() throws IOException{
        InputStream is = Resources.getResourceAsStream("mybatis-config.xml");
        SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();
        SqlSessionFactory sqlSessionFactory = sqlSessionFactoryBuilder.build(is);
        SqlSession sqlSession = sqlSessionFactory.openSession(true);
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        User user = mapper.getUser();
       System.out.println(user);
   }

（2）查詢所有

UserMapper.java中添加查詢方法

    //查詢所有
    List<User> getUserAll();

UserMapper.xml中寫sql陳述句

    <!--List<User> getUserAll();-->
    <select id="getUserAll" resultType="com.tinstu.mybatis.pojo.User">
        select * from user
    </select>

測驗類：

   @Test
    public void testuodate() throws IOException{
        InputStream is = Resources.getResourceAsStream("mybatis-config.xml");
        SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();
        SqlSessionFactory sqlSessionFactory = sqlSessionFactoryBuilder.build(is);
        SqlSession sqlSession = sqlSessionFactory.openSession(true);
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
       List<User> userList = mapper.getUserAll();
       System.out.println(userList);
       //lanmbda運算式
       userList.forEach(user -> System.out.println(user));
   }

我的java筆記：mybatis環境搭建及測驗： https://www.tinstu.com/1218.html

本文來自博客園，作者：Tinstu.com，轉載請注明原文鏈接：https://www.cnblogs.com/tinstu/p/16191089.html

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標籤：Java

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