spring整合mybatis

spring整合mybatis

导入相关jar包

<dependencies>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.25</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.6</version>
        </dependency>
        <!--Spring-JDBC数据源依赖 -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>5.3.22</version>
        </dependency>
<!--        aspectJ AOP 织入器-->
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.8.14</version>
        </dependency>
<!--        mybatis-spring整合包 【重点】-->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
            <version>2.0.2</version>
        </dependency>
    </dependencies>
<!--    配置Maven静态资源过滤问题！-->
    <build>
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
        </resources>
    </build>

回忆Mybatis

编写pojo实体类

package com.bai.pojo;

public class User {
    private int id;
    private String name;
    private String pwd;
//getter和setter方法
//有参和无参构造
//toString方法

实现mybatis的配置文件

<?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.bai.pojo"/>
    </typeAliases>

    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.cj.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/mybatis"/>
                <property name="username" value="root"/>
                <property name="password" value="root"/>
            </dataSource>
        </environment>
    </environments>

    <mappers>
        <package name="com.bai.dao"/>
    </mappers>
</configuration>

UserDao接口编写

public interface UserMapper {
   public List<User> selectUser();
}

接口对应的Mapper映射文件

<?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.kuang.dao.UserMapper">

   <select id="selectUser" resultType="User">
    select * from user
   </select>

</mapper>

测试类

@Test
public void selectUser() throws IOException {

   String resource = "mybatis-config.xml";
   InputStream inputStream = Resources.getResourceAsStream(resource);
   SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
   SqlSession sqlSession = sqlSessionFactory.openSession(true);

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

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

   sqlSession.close();
}

spring整合mybatis： MyBatis-Spring

什么是 MyBatis-Spring？

MyBatis-Spring 会帮助你将 MyBatis 代码无缝地整合到 Spring 中。

整合实现一：

1、引入Spring配置文件beans.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.xsd">
</beans>

2、配置数据源替换mybaits的数据源

<!--    DataSource:使用spring的配置，将数据源替换mybatis-config的配置文件
    常用的数据源  c3p0 dbcp druid  这里我们使用spring提供的JDBC-->
    <bean id="datasource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="com.mysql.cj.jdbc.Driver"/>
        <property name="url" value="jdbc:mysql://localhost:3306/mybatis"/>
        <property name="username" value="root"/>
        <property name="password" value="root"/>
    </bean>

3、配置SqlSessionFactory，关联MyBatis

<!--配置SqlSessionFactory-->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="datasource"/>
        <!--关联Mybatis-->
        <property name="configLocation" value="classpath:mybatis-config.xml"/>
        <property name="mapperLocations" value="classpath:com/bai/dao/*.xml"/>
    </bean>

4、注册sqlSessionTemplate，关联sqlSessionFactory；

<!--    SqlSessionTemplate:就是我们使用的sqlSession-->
    <bean id="sqlsession" class="org.mybatis.spring.SqlSessionTemplate">
    <!--        只能使用构造器注入sqlSessionFactory，因为她没有set方法-->
        <constructor-arg index="0" ref="sqlSessionFactory"/>
    </bean>

5、增加Dao接口的实现类；私有化sqlSessionTemplate

package com.bai.dao;
import com.bai.pojo.User;
import org.mybatis.spring.SqlSessionTemplate;
import java.util.List;

public class UserMapperImpl implements UserMapper{

    //我们的所有操作，都使用sqlSession来执行，在原来，现在都使用SqlSessionTemplate
    private SqlSessionTemplate sqlSession;

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

    //查询所有用户
    public List<User> getAllUser() {
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        return mapper.getAllUser();
    }

6、注册bean实现

<bean id="usermapper" class="com.bai.dao.UserMapperImpl">
        <property name="sqlSession" ref="sqlsession"></property>
    </bean>

7、测试

 @Test
    public void getAllUserTest() {
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        UserMapperImpl usermapper = context.getBean("usermapper", UserMapperImpl.class);
        List<User> allUser = usermapper.getAllUser();
        for (User user : allUser) {
            System.out.println(user);
        }
    }

mybatis-config.xml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.bai.pojo"/>
    </typeAliases>

<!--    <environments default="development">-->
<!--        <environment id="development">-->
<!--            <transactionManager type="JDBC"/>-->
<!--            <dataSource type="POOLED">-->
<!--                <property name="driver" value="com.mysql.cj.jdbc.Driver"/>-->
<!--                <property name="url" value="jdbc:mysql://localhost:3306/mybatis"/>-->
<!--                <property name="username" value="root"/>-->
<!--                <property name="password" value="root"/>-->
<!--            </dataSource>-->
<!--        </environment>-->
<!--    </environments>-->

<!--    <mappers>-->
<!--        <package name="com.bai.dao"/>-->
<!--    </mappers>-->
</configuration>

整合实现二：

mybatis-spring1.2.3版以上的才有这个 .

dao继承Support类 , 直接利用 getSqlSession() 获得 , 然后直接注入SqlSessionFactory . 比起方式1 , 不需要管理SqlSessionTemplate , 而且对事务的支持更加友好 . 可跟踪源码查看
1、将我们上面写的UserDaoImpl修改一下

public class UserDaoImpl extends SqlSessionDaoSupport implements UserMapper {
   public List<User> selectUser() {
       UserMapper mapper = getSqlSession().getMapper(UserMapper.class);
       return mapper.selectUser();
  }
}

2、修改bean的配置

<bean id="userDao" class="com.kuang.dao.UserDaoImpl">
   <property name="sqlSessionFactory" ref="sqlSessionFactory" />
</bean>

3、测试

@Test
public void test2(){
   ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
   UserMapper mapper = (UserMapper) context.getBean("userDao");
   List<User> user = mapper.selectUser();
   System.out.println(user);
}

总结 :

整合到spring以后可以完全不要mybatis的配置文件，除了这些方式可以实现整合之外，我们还可以使用注解来实现，这个等我们后面学习SpringBoot的时候还会测试整合！