12 整合MyBatis

步骤：

1. 导入相关jar包
   • junit
   • mybatis
   • mysql 数据库
   • spring 相关
   • aop 织入
   • mybatis-spring

    <dependencies>
        <!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.3.14</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework/spring-jdbc -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>5.3.14</version>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.aspectj/aspectjweaver -->
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.9.7</version>
            <scope>runtime</scope>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.44</version>
        </dependency>

        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.2</version>
        </dependency>

        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.9.7</version>
        </dependency>

        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
            <version>2.0.2</version>
        </dependency>
    </dependencies>

2. 编写配置文件
3. 测试

12.1 回忆mybatis

1. 编写实体类

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

2. 编写核心配置文件

<?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>
    <typeAliases>
        <package name="com.hunter.pojo"/>
    </typeAliases>

    <!--设置-->
    <!--<settings>
        <setting name="" value=""/>
    </settings>-->

    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/test_db?useSSL=true&amp;useUnicode=true&amp;characterEncoding=UTF-8&amp;serverTimezone=UTC"/>
                <property name="username" value="root"/>
                <property name="password" value="root"/>
            </dataSource>
        </environment>
    </environments>
    
    <mappers>
        <mapper class="com.hunter.mapper.UserMapper"/>
    </mappers>
</configuration>

3. 编写接口

import com.hunter.pojo.User;
import java.util.List;
public interface UserMapper {
    public List<User> selectUser();
}

4. 编写Mapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.hunter.mapper.UserMapper">
    <select id="selectUser" resultType="User">
        SELECT * FROM test_db.user;
    </select>
</mapper>

5. 测试

public class MyTest {
    @Test
    public void test() throws IOException {
        InputStream in = Resources.getResourceAsStream("mybatis-config.xml");
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(in);
        SqlSession sqlSession = sqlSessionFactory.openSession(true);

        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        List<User> userList = mapper.selectUser();
        for (User user : userList){
            System.out.println(user);
        }
    }
}

12.2 Mybatis-Spring

1. 编写数据源/SqlSessionFactory/SqlSessionTemplate

<?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
        https://www.springframework.org/schema/beans/spring-beans.xsd">
    <!--DataSource: 使用Spring的数据源替换MyBatis的配置 c3p0 dbcp druid
    我们这里使用Spring 提供的JDBC: org.springframework.jdbc.datasource
    -->
    <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/test_db?useSSL=true&amp;useUnicode=true&amp;characterEncoding=UTF-8&amp;serverTimezone=UTC"/>
        <property name="username" value="root"/>
        <property name="password" value="root"/>
    </bean>

    <!--SqlSessionFactory-->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <!--绑定MyBatis 配置文件-->
        <property name="configLocation" value="classpath:mybatis-config.xml"/>
        <property name="mapperLocations" value="classpath:com/hunter/mapper/*.xml"/>
    </bean>
    <!--SqlSessionTemplate: 就是我们使用的SqlSession-->
    <bean id="sqlSessionTemplate" class="org.mybatis.spring.SqlSessionTemplate">
        <!--只能使用构造器注入：SqlSessionFactory，因为它没有set方法-->
        <constructor-arg index="0" ref="sqlSessionFactory"/>
    </bean>
</beans>

4. 需要给接口加实现类

import com.hunter.pojo.User;
import org.mybatis.spring.SqlSessionTemplate;
import java.util.List;

public class UserMapperImpl implements UserMapper{
    public void setSqlSessionTemplate(SqlSessionTemplate sqlSessionTemplate) {
        this.sqlSessionTemplate = sqlSessionTemplate;
    }

    // 我们的所有操作都使用SqlSessionTemplate
    private SqlSessionTemplate sqlSessionTemplate;

    @Override
    public List<User> selectUser() {
        UserMapper mapper = sqlSessionTemplate.getMapper(UserMapper.class);
        return mapper.selectUser();
    }
}

5. 将自己写的实现类注入到Spring中，测试使用

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        https://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/aop
        https://www.springframework.org/schema/aop/spring-aop.xsd">

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

    <bean id="userMapper" class="com.hunter.mapper.UserMapperImpl">
        <property name="sqlSessionTemplate" ref="sqlSessionTemplate"/>
    </bean>
</beans>

import com.hunter.mapper.UserMapper;
import com.hunter.mapper.UserMapperImpl;
import com.hunter.pojo.User;
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 org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

public class MyTest {
    @Test
    public void test() throws IOException {
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        UserMapper userMapper = context.getBean("userMapper", UserMapper.class);
        for (User user: userMapper.selectUser()){
            System.out.println(user);
        }
    }
}