Integrating mybatis and spring

1. First, recall the steps to write the mybatis project

• Import database

• Guide bag

  • junit
  • mybatis
  • mysql connection driver

• Write entity classes based on databases

• Write mybatis configuration file (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>
      ...
  </configuration>    
  

• Writing interfaces

• Write mapper mapping file corresponding to interface

  <?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="[Interface]">
      ...
  </mapper>
  

• Register mapper mapping file in mybatis-config.xml

   <mappers>
          <mapper resource="../[mapper.xml]"/>
   </mappers>
  

• Write test files

  InputStream resource = Resources.getResourceAsStream("mybatis-config.xml");
          SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resource);
          SqlSession sqlSession = sqlSessionFactory.openSession(true);
          UserDao mapper = sqlSession.getMapper([Interface name].class);
  

2.Spring integrates MyBatis

[Preliminary preparation]

Understanding an important package: MyBatis-Spring

MyBatis-Spring: http://www.mybatis.org/spring/zh

Let's go and have a look. I've extracted some knowledge points that need to be known:

• The role of MyBatis-Spring:

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

• The required version of MyBatis-Spring:

  MyBatis-Spring	MyBatis	Spring Framework	Spring Batch	Java
  2.0	3.5+	5.0+	4.0+	Java 8+
  1.3	3.4+	3.2.2+	2.1+	Java 6+

  According to my own situation, I chose version 1.3.

  Guide packages:

  I use Maven as a build tool, so I just need to add the following code in pom.xml:

  <!-- The version I chose is 1.3.2 -->
  <dependency>
    <groupId>org.mybatis</groupId>
    <artifactId>mybatis-spring</artifactId>
    <version>1.3.2</version>
  </dependency>
  

• How to use MyBatis with Spring:

  • On sqlSession Factory

    In the basic MyBatis usage, SqlSession Factory is created through SqlSession Factory Builder. In MyBatis-Spring, SqlSessionFactory Bean can be used to create SqlSessionFactory. To configure the factory bean, just put the following code in Spring's XML configuration file:

    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
      <property name="dataSource" ref="dataSource" />
    </bean>
    

    Note: SqlSession Factory needs a Data Source. This can be any DataSource, just configure it as you configure other Spring database connections.

  • On SqlSession

    In MyBatis, you can use SqlSession Factory to create SqlSession. Once you have a session, you can use it to execute mapped statements, submit or roll back connections, and finally close the session when it is no longer needed. With MyBatis-Spring, you no longer need to use SqlSession Factory directly, because your bean can be injected into a thread-safe SqlSession, which can automatically commit, rollback, and close sessions based on Spring's transaction configuration.

  • On SqlSession Template

    SqlSession Template is the core of MyBatis-Spring.

    As an implementation of SqlSession, this means that it can seamlessly replace the SqlSession already in use in your code. SqlSession Template is thread-safe and can be shared by multiple DAO s or mappers.

    SqlSessionTemplate objects can be created using SqlSessionFactory as a parameter to the constructor.

    <bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate">
      <constructor-arg index="0" ref="sqlSessionFactory" />
    </bean>
    

[Example]

Look at the front, you may be a bit confused, so let's write a project directly.

Overall project structure:

<1. Guide Pack

       <!--unit testing-->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
        </dependency>

        <!--mybaits-->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.4.6</version>
        </dependency>

        <!--mysql Connection Driver-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.47</version>
        </dependency>

        <!--Spring Package-->
        <!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>4.3.9.RELEASE</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.springframework/spring-jdbc -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>4.3.9.RELEASE</version>
        </dependency>


        <!--mybatis-spring-->
        <!-- https://mvnrepository.com/artifact/org.mybatis/mybatis-spring -->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
            <version>1.3.2</version>
        </dependency>

<2. Configure mybatis file

Simply write some simple settings, aliases and register mapper mapping files

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>

    <!--Alias-->
    <typeAliases>
        <package name="priv.sehun.pojo"/>
    </typeAliases>

    <!--Registration mapping file-->
    <mappers>
        <mapper resource="priv/sehun/dao/UserMapper.xml"/>
    </mappers>

</configuration>

< 3. Write spring configuration file

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"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd">

    <!--1.Configuring data sources,What we're using is spring A third-party data source can also be used-->
    <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="123456"/>
    </bean>

    <!--2.To configure SqlSessionFactory-->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource" />
        <!--Relation mybatis Configuration file-->
        <property name="configLocation" value="classpath:mybatis-config.xml"/>
    </bean>

    <!--3.Establish selSession-->
    <bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate">
        <constructor-arg index="0" ref="sqlSessionFactory" />
    </bean>

    <!--4.Interface Implementing Class Injection sqlSession-->
    <!--Deliver the implementation class of the interface to spring To manage-->
    <bean id="userDaoImpl" class="priv.sehun.dao.UserDaoImpl">
        <property name="sqlSession" ref="sqlSession"/>
    </bean>


</beans>

<4. Interface, Interface Implementation Class, Interface Mapping File

UserDao

public interface UserDao {
    //Get all user information
    List<User> selectUser();
}

UserDaoImpl

import org.mybatis.spring.SqlSessionTemplate;
import priv.sehun.pojo.User;

import java.util.List;

public class UserDaoImpl implements UserDao {

    private SqlSessionTemplate sqlSession;

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

    public List<User> selectUser() {

        UserDao mapper = sqlSession.getMapper(UserDao.class);
        return mapper.selectUser();

    }
}

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="priv.sehun.dao.UserDao">
    <select id="selectUser" resultType="User">
        select * from mybatis.user
    </select>
</mapper>

< 5. Test class

Note, don't mistake the bag.

import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import priv.sehun.pojo.User;

import java.util.List;

public class UserTest {
    @Test
    public void test(){
        //Parse the beans.xml configuration file and manage the corresponding Bean objects in production.
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");

        //Get the entity of the object through the Bean
        UserDao userDaoImpl = (UserDao) context.getBean("userDaoImpl");
        List<User> users = userDaoImpl.selectUser();

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

<6 Running results

affair

Transaction Details

See a blog: https://blog.csdn.net/weixin_40263776/article/details/79521595

Detailed description of Java transactions, why Java transactions are needed, and the types of Java transactions.

Configure transactions for spring

Spring supports two transaction processing mechanisms:

• Programming Transactions: Write the code of all transactions in the business;
• Declarative transactions: use AOP to cross-cut in;

General use of declarative transactions

code implementation

1. Guide bag

2. A transaction manager needs to be configured, and a data source is needed for the parameters.

   <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
       <constructor-arg ref="dataSource" />
   </bean>
   

3. Configuration declaration transaction notification

   <! - Configuration declaration transaction notification - >
   <tx:advice id="txAdvice" transaction-manager="transactionManager">
       <tx:attributes>
           <!--
           name: Which methods use transactions [methods]
           Propagation: Configuring the propagation characteristics of transactions
           REQUIRED: If there is no transaction, create a new one.
           -->
           <tx:method name="add" propagation="REQUIRED"/>
           <tx:method name="delete" propagation="REQUIRED"/>
           <tx:method name="get*" read-only="true"/>
           <tx:method name="*" propagation="REQUIRED"/>
   
       </tx:attributes>
   </tx:advice>
   

4. Configure aop to weave transactions

   <!--To configure aop Weave in business-->
   <aop:config>
       <!--breakthrough point-->
       <aop:pointcut id="txPointCut" expression="execution(* com.kuang.dao.UserDaoImpl.*(..))"/>
       <!--notice-->
       <aop:advisor advice-ref="txAdvice" pointcut-ref="txPointCut"/>
   </aop:config>
   

Developing with annotations

bean

1. Guide package;

2. Add a constraint in the configuration file: context;

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

3. Configure Scanning Component

   <! - Auto-scan the annotations under the specified package - >
   <context:component-scan base-package="priv.sehun.demo"/>
   

4. Write code:

   //Equivalent to: <bean id="user1" class="priv.sehun.demo.User"/>
   
   /*
   @Component : Component bean s
   @Controller : web layer
   @Service :  service layer
   @Repository : dao layer
    */
   
   @Component("user1")
   public class User1 {
       public String name = "Dog";
   }
   

IOC injection

1. Instead of providing a set method, you can add an @Values (value) directly to the attribute name.

@Controller("user2")
public class User2 {
    @Value("Dog")
    private String name;

    public String getName() {
        return name;
    }
}

1. If there is a set, add @Values (value) directly to the set method.

@Controller("user2")
public class User2 {
    private String name;

    public String getName() {
        return name;
    }
    
    @Value("Qin Jiang")
    public void setName(String name) {
        this.name = name;
    }
}