第四周------spring整合mybatis框架

spring框架整合mybatis

讓我們一起來感受框架的強大，和spring配置地獄的瘋狂吧

專案檔案目錄

組態檔

spring的核心配置 /spring-dao.xml

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">

<!--    DataSource：使用Spring的資料源替換Mybatis的配置-->
<!--    這里使用spring提供的jdbc-->
    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
        <property name="url" value="jdbc:mysql://localhost:3306/mybatis?useSSL=true&amp;useUnicode=true&amp;characterEncoding=UTF-8"/>
        <property name="username" value="root"/>
        <property name="password" value="root"/>
    </bean>

    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource" />
<!--        系結mybatis組態檔-->
        <property name="configLocation" value="classpath:mybatis-config.xml"/>
<!--        系結mybatis組態檔中的Mapper介面的xml檔案-->
        <property name="mapperLocations" value="classpath:com/huang/mapper/*.xml"/>
    </bean>

    <bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate">
<!--        只能使用構造器注入sqlSessionFactory，因為它沒有set方法-->
        <constructor-arg index="0" ref="sqlSessionFactory"/>
    </bean>
</beans>

mybatis核心配置 /mybatis-config.xml
該檔案中通常都只留下設定和別名，其余可以在spring組態檔配置

<?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>
<!--    <properties resource="db.properties"/>-->
    <settings>
        <setting name="logImpl" value="STDOUT_LOGGING"/>
        <setting name="mapUnderscoreToCamelCase" value="true" />
    </settings>
    <typeAliases>
        <package name="com.huang.pojo"/>
    </typeAliases>

</configuration>

最終讀取的組態檔 /applicationContext.xml 將控制層的業務放在此檔案，同時整合/spring-dao.xml檔案中資料源和sqlSession等的配置，最后CPX中讀取該檔案即可，實作了組態檔的分工

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">

    <import resource="spring-dao.xml"/>

    <bean id="userMapper" class="com.huang.mapper.UserMapperImpl">
        <property name="sqlSession" ref="sqlSession"/>
    </bean>

</beans>

提示：在實作了以上三個組態檔的分層，spring的核心配置 /spring-dao.xml基本可以寫死，可以作為默認檔案保存為模板，以后直接使用即可，簡化了我們的操作

pojo類

lombok配置在上篇博客已經有說明

package com.huang.pojo;
import lombok.Data;
@Data
public class User {
    private int id;
    private String name;
    private String pwd;
}

Mapper介面和介面xml和實作類

public interface UserMapper {
    List<User> getUserList(int id);
}

<?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.huang.mapper.UserMapper">
    <select id="getUserList" resultType="user">
        select * from mybatis.user where id = #{id};
    </select>
</mapper>

關鍵是實作mapper介面類的代碼（注意理解各個檔案之間的邏輯）

package com.huang.mapper;

import com.huang.pojo.User;
import org.apache.ibatis.session.SqlSession;

import java.util.List;

public class UserMapperImpl implements UserMapper{
    private SqlSession sqlSession;

    public void setSqlSession(SqlSession sqlSession) {
        this.sqlSession = sqlSession;
    }

    @Override
    public List<User> getUserList(int id) {
        return sqlSession.getMapper(UserMapper.class).getUserList(id);
    }
}

我們不必再通過new來得到sqlSession了，而是使用spring的set注入來獲得sqlSession物件，
業務邏輯的介面都在application.xml中使用bean來配置 此處一定要理解各個檔案之間的邏輯與聯系，

<bean id="userMapper" class="com.huang.mapper.UserMapperImpl">
    <property name="sqlSession" ref="sqlSession"/>
</bean>

測驗類

public class UserMapperTest {
    @Test
    public void test1() throws IOException {
//原來沒整合前的代碼         
//        String resources = "mybatis-config.xml";
//        InputStream inputStream = Resources.getResourceAsStream(resources);
//        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
//        SqlSession sqlSession = sqlSessionFactory.openSession(true);
//        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
//        List<User> userList = mapper.getUserList();
//        for (User user : userList) {
//            System.out.println(user);
//        }
//        sqlSession.close();

        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        UserMapper userMapper = context.getBean("userMapper", UserMapper.class);
        for (User user : userMapper.getUserList(1)) {
            System.out.println(user);
        }
    }
}

整合易錯點：

org.springframework.core.ResolvableType org.springframework.beans.factory.co
spring-framework 核心包版本必須保持一致