【Spring】(十二)整合Mybatis

整合Mybatis

1.环境搭建（mybatis）

1.导入相关jar包

junit
mybatis
mysql数据库
spring相关（springframework，spring-jdbc）
aop织入
mybatis-spring【new】
lombok

<dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.47</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.2</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.2.12.RELEASE</version>
        </dependency>
        <!-- Spring操作数据库，需要spring-jdbc -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>5.2.12.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.9.6</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.mybatis/mybatis-spring -->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
            <version>2.0.6</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.16.10</version>
        </dependency>
</dependencies>

<build>
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
        </resources>
</build>

2.编写实体类

User

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

3.编写核心配置文件

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>
    <typeAliases>
        <package name="pojo"/>
    </typeAliases>
    
    <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/MyBatiss?useSSL=true&amp;useUnicode=true&amp;characterEncoding=UTF-8"/>
                <property name="username" value="root"/>
                <property name="password" value="root"/>
            </dataSource>
        </environment>
    </environments>

    <!--每一个Mapper.xml都需要在Mybatis核心配置文件中注册！-->
    <mappers>
        <mapper resource="mapper/UserMapper.xml"/>
    </mappers>
</configuration>

4.编写接口

UserMapper

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

5.编写Mapper.xml

UserMapper.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="mapper.UserMapper">

    <select id="selectUser" resultType="user">
        select * from mybatiss.user;
    </select>

</mapper>

6.工具类

MybatisUtils

public class MybatisUtils {
    private static SqlSessionFactory sqlSessionFactory;

    static {
        try {
            //获取SqlSessionFactory对象
            String resource = "mybatis-config.xml";
            InputStream in = Resources.getResourceAsStream(resource);
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(in);

        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static SqlSession getSqlSession() {
        return sqlSessionFactory.openSession(true);//开启自动提交事务
    }
}

7.测试

MyTest

public class MyTest {
    
    @Test
    public void test()  {
        SqlSession sqlSession = MybatisUtils.getSqlSession();

        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        List<User> userList=mapper.selectUser();

        for (User user : userList) {
            System.out.println(user);
        }

        sqlSession.close();
    }
}

2. Mybatis和spring的整合

步骤：

1.编写数据源配置

2.sqlSessionFactory

3.sqlSessionTemplate

4.需要给接口加实现类

5.将自己写的实现类，注入到Spring中

6.测试

2.1 整合方式一

1.spring-dao.xml 配置文件

<?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">

    <!--DataSource：使用Spring的数据源替换Mybatis的配置  c3p0  dbcp  druid
    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/mybatiss?useSSL=true&amp;useUnicode=true&amp;characterEncoding=UTF-8" />
        <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核心配置文件-->
        <property name="configLocation" value="classpath:mybatis-config.xml"/>
        <property name="mapperLocations" value="classpath:mapper/*.xml" />
    </bean>

    <!--SqlSessionTemplate：相当于我们之前使用的sqlSession-->
    <bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate">
        <!--只能使用构造器注入sqlSessionFactory，因为没有set方法-->
        <constructor-arg index="0" ref="sqlSessionFactory" />
    </bean>


</beans>

2.删除mybatis-config.xml多余内容

<?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="pojo"/>
    </typeAliases>

</configuration>

3.总配置文件 applicationContext.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"
       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" />

    <!--注册bean-->
    <bean id="userMapper" class="mapper.UserMapperImpl">
        <property name="sqlSession" ref="sqlSession" />
    </bean>

</beans>

4.User类，UserMapper接口不变，删除MybatisUtils工具类

增加UserMapperImpl实现类

public class UserMapperImpl implements UserMapper {

    //原来我们所有的操作都用sqlSession来执行，现在都使用SqlSessionTemplate
    private SqlSessionTemplate sqlSession;

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

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

5.测试

 @Test
    public void test2() {
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");

        UserMapper userMapper = context.getBean("userMapper", UserMapper.class);
        List<User> userList = userMapper.selectUser();
        for (User user : userList) {
            System.out.println(user);
        }
    }

Spring整合Mybatis：将原本应该由程序去调用mybatis代码产生Mapper代理对象的过程交给了Spring，我们在Spring配置文件中可以配置Mybatis的配置信息，从而让Spring帮我们创建了Mybatis相关对象（SqlSessionFactory对象、SqlSessionTemplate对象），从而去管理Mapper对象。

【参考】https://www.sohu.com/a/285808583_194621

2.2 整合方式二

通过让实现类UserMapperImpl2继承SqlSessionDaoSupport

public class UserMapperImpl2 extends SqlSessionDaoSupport implements UserMapper {

    public List<User> selectUser() {
        return getSqlSession().getMapper(UserMapper.class).selectUser();
    }
}

applicationContext.xml中

<bean id="userMapper2" class="mapper.UserMapperImpl2">
        <property name="sqlSessionFactory" ref="sqlSessionFactory"/>
</bean>

spring-dao.xml中不用再配置SqlSessionTemplate了

posted @ 2021-01-27 21:45 musecho 阅读(62) 评论(0) 收藏举报

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musecho