Spring integrates Mybatis (mad god)

step

Import related jar packages

• junit
• my shoe
• mysql database
• spring-related
• aop weaver
• The mybatis-spring integration package [key] also imports the lombok package here.
• Configure Maven static resource filtering problem!

    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.6</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.47</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.2.0.RELEASE</version>
        </dependency>
        <!--Spring操作数据库的话，还需要一个spring-jdbc
               -->
        <!-- https://mvnrepository.com/artifact/org.springframework/spring-jdbc -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>5.2.0.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.8.13</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.mybatis/mybatis-spring -->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
            <version>2.0.2</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.10</version>
        </dependency>
    </dependencies>

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

2. Write configuration file
3. Test

recall mybatis

1. Write pojo entity class

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

2. Write the configuration file that implements mybatis

<?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.kuang.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/mybatis?useSSL=false&amp;useUnicode=true&amp;characterEncoding=utf8"/>
               <property name="username" value="root"/>
               <property name="password" value="123456"/>
           </dataSource>
       </environment>
   </environments>

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

3. Write the UserMapper interface

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

4. Write the UserMapper.xml file

<?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.mapper.UserMapper">

    <!--sql-->
    <select id="selectUser" resultType="user">
        select * from mybatis.user
    </select>
</mapper>

5. Test

@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();

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

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

   sqlSession.close();
}

Mybatis-Spring

What is MyBatis-Spring?

MyBatis-Spring will help you seamlessly integrate MyBatis code into Spring.

Document link: http://mybatis.org/spring/zh/index.html

If you use Maven as a build tool, you only need to add the following code to pom.xml:

        <!-- https://mvnrepository.com/artifact/org.mybatis/mybatis-spring -->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
            <version>2.0.2</version>
        </dependency>

Integration implementation one:

1. Introduce the Spring configuration file spring-dao.xml

<?xml version="1.0" encoding="GBK"?>
<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

</beans>

2. Configure the data source to replace the data source of mybaits

    <!--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：-->
    <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=false&amp;useUnicode=true&amp;characterEncoding=UTF-8"/>
        <property name="username" value="root"/>
        <property name="password" value="123456"/>
    </bean>

3. Configure SqlSessionFactory and associate MyBatis

    <!--sqlSessionFactory-->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource" />
        <!--关联mybatis配置文件-->
        <property name="configLocation" value="classpath:mybatis-config.xml"/>
        <property name="mapperLocations" value="classpath:com/kuang/mapper/*.xml"/>
    </bean>

4. Register sqlSessionTemplate and associate 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，因为它没有set方法-->
        <constructor-arg index="0" ref="sqlSessionFactory" />
    </bean>

5. Need UserMapperImpl implementation class of UserMapper interface, privatize sqlSessionTemplate

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;
    }

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

6. Inject the implementation class written by yourself into the Spring configuration file.

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

7. Test and use it!

    @Test
    public void test () throws IOException {
    
    

        ApplicationContext context = new ClassPathXmlApplicationContext("spring-dao.xml");
        
        UserMapper userMapper = context.getBean("userMapper", UserMapper.class);
        for (User user : userMapper.selectUser()) {
    
    
            System.out.println(user);
        }
    }

The result is successfully output! Now the status of our Mybatis configuration file! Discovery can be integrated by Spring!

<?xml version="1.0" encoding="GBK" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<!--configuration core file-->
<configuration>
    
    <typeAliases>
        <package name="com.kuang.pojo"/>
    </typeAliases>
</configuration>

Integration implementation two:

This is only available for mybatis-spring version 1.2.3 and above. Screenshot of the official document:

dao inherits the Support class, directly uses getSqlSession() to obtain it, and then directly injects it into SqlSessionFactory. Compared with the integration method 1, it does not need to manage SqlSessionTemplate, and it supports transactions more friendly. You can track the source code to view.

test:

1. Modify the UserMapperImpl we wrote above

public class UserMapperImpl extends SqlSessionDaoSupport implements UserMapper {
    
    

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

2. Inject into the Spring configuration file.

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

3. Test

    @Test
    public void test () throws IOException {
    
    

        ApplicationContext context = new ClassPathXmlApplicationContext("spring-dao.xml");
        
        UserMapper userMapper = context.getBean("userMapper", UserMapper.class);
        for (User user : userMapper.selectUser()) {
    
    
            System.out.println(user);
        }
    }