[Java知识库]Spring与MyBatis整合

一、SM整合的步骤

1.pom文件

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.sm</groupId>
  <artifactId>Spring-MyBatis</artifactId>
  <version>1.0-SNAPSHOT</version>
  
  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>8</maven.compiler.source>
    <maven.compiler.target>8</maven.compiler.target>
  </properties>

  <dependencies>
    <!--单元测试的依赖-->
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.13.2</version>
      <scope>test</scope>
    </dependency>
    <!--aspectj的依赖-->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-aspects</artifactId>
      <version>5.3.23</version>
    </dependency>
    <!--spring核心依赖-->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
      <version>5.3.23</version>
    </dependency>
    <!--spring事务的依赖-->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-tx</artifactId>
      <version>5.3.23</version>
    </dependency>
    <dependency>
      <groupId>springframework</groupId>
      <artifactId>spring-jdbc</artifactId>
      <version>1.2.6</version>
    </dependency>
    <!--mybatis依赖-->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis</artifactId>
      <version>3.5.11</version>
    </dependency>
    <!--mybatis和spring集成依赖-->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis-spring</artifactId>
      <version>2.0.7</version>
    </dependency>
    <!--mysql驱动依赖-->
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>8.0.30</version>
    </dependency>
    <!--阿里数据库连接池-->
    <dependency>
      <groupId>com.alibaba</groupId>
      <artifactId>druid</artifactId>
      <version>1.2.12</version>
    </dependency>
  </dependencies>

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

2.applicationContext_mapper.xml文件整合mybatis核心配置文件

<?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: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/context https://www.springframework.org/schema/context/spring-context.xsd">

    <!--读取属性文件 jdbc.properties-->
    <context:property-placeholder location="jdbc.properties"/>
    <!--创建数据源-->
    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
        <property name="driver" value="${jdbc.driver}"/>
        <property name="url" value="${jdbc.url}"/>
        <property name="username" value="${jdbc.username}"/>
        <property name="password" value="${jdbc.password}"/>
    </bean>
    <!--配置SqlSessionFactoryBean类-->
    <bean class="org.mybatis.spring.SqlSessionFactoryBean">
        <!--配置数据源-->
        <property name="dataSource" ref="dataSource"/>
        <!--配置mybatis的核心配置文件-->
        <property name="configLocation" value="mybatis-config.xml"/>
        <!--注册实体类的别名-->
        <property name="typeAliasesPackage" value="com.sm.bean"/>
    </bean>
    <!--注册mapper.xml文件-->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="com.sm.mapper"/>
    </bean>
</beans>

3.applicationContext_service.xml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: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/context https://www.springframework.org/schema/context/spring-context.xsd">
    
    <!--SM是基于注解开发的,所以添加包扫描-->
    <context:component-scan base-package="com.sm.service"/>
    <!--事务处理-->
</beans>

4.添加注解式事务

<?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:context="http://www.springframework.org/schema/context" xmlns:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd">

    <!--导入applicationContext_mapper.xml文件-->
    <import resource="applicationContext_mapper.xml"/>

    <!--SM是基于注解开发的,所以添加包扫描-->
    <context:component-scan base-package="com.sm.service"/>

    <!--事务处理-->
    <!--1.添加事务管理器-->
    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <!--因为事务必须关联数据库处理,所以要配置数据源-->
        <property name="dataSource" ref="dataSource"/>
    </bean>
    <!--2.添加事务的注解驱动-->
    <tx:annotation-driven transaction-manager="transactionManager"/>
</beans>

@Service("accountsServiceImpl")
@Transactional(propagation = Propagation.REQUIRED)
public class AccountsServiceImpl implements AccountsService {}

/**
 * propagation = Propagation.REQUIRED事务的传播特性
 * noRollbackForClassName 指定发生什么异常不回滚,使用异常的名称
 * noRollbackFor 指定发生什么异常不回滚,使用异常的类型
 * rollbackForClassName 指定发生什么异常必须回滚
 * rollbackFor 指定发生什么异常必须回滚
 * timeout = -1 连接超时设置,默认式-1,表示永不超时
 * readOnly = false 默认是false，如果是查询操作,必须设置为true
 * isolation = Isolation.DEFAULT 使用数据库自己的隔离级别
 */
@Transactional(propagation = Propagation.REQUIRED,
               noRollbackForClassName = "ArithmeticException",
               noRollbackFor = ArithmeticException.class,
               timeout = -1,
               readOnly = false,
               isolation = Isolation.DEFAULT)

二、spring的事务处理

1.注解式事务

使用@Transactional注解完成事务控制
（1）
可以添加到类上，则对类中所有的方法执行此事务设定
（2）
可以添加到方法上，只对此方法执行此事务处理

2.声明式事务(必须掌握)

在配置文件中添加一次，整个项目遵循事务设定。

要求项目中的方法命名有规范
（1）完成增加操作必须包含 add,save,insert set
（2）更新操作必须包含 update change modify
（3）删除操作包含 delete drop remove clead
（4）查询操作包含 select find search get

这样做的话，配置事务切面的时候可以使用 通配符* 来匹配所有方法

<?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:context="http://www.springframework.org/schema/context" xmlns:tx="http://www.springframework.org/schema/tx"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd http://www.springframework.org/schema/aop https://www.springframework.org/schema/aop/spring-aop.xsd">

    <!--导入applicationContext_mapper.xml文件-->
    <import resource="applicationContext_mapper.xml"/>

    <!--SM是基于注解开发的,所以添加包扫描-->
    <context:component-scan base-package="com.sm.service"/>

    <!--事务处理-->
    <!--1.添加事务管理器-->
    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <!--因为事务必须关联数据库处理,所以要配置数据源-->
        <property name="dataSource" ref="dataSource"/>
    </bean>
    <!--2.添加事务的注解驱动-->
<!--    <tx:annotation-driven transaction-manager="transactionManager"/>-->
    <!--配置事务切面-->
    <tx:advice id="maAdvice" transaction-manager="transactionManager">
        <tx:attributes>
            <tx:method name="*select*" read-only="true"/>
            <tx:method name="*find*" read-only="true"/>
            <tx:method name="*search*" read-only="true"/>
            <tx:method name="*get*" read-only="true"/>
            <tx:method name="*insert*" propagation="REQUIRED"/>
            <tx:method name="*add*" propagation="REQUIRED"/>
            <tx:method name="*save*" propagation="REQUIRED"/>
            <tx:method name="*set*" propagation="REQUIRED"/>
            <tx:method name="*update*" propagation="REQUIRED"/>
            <tx:method name="*change*" propagation="REQUIRED"/>
            <tx:method name="*modify*" propagation="REQUIRED"/>
            <tx:method name="*delete*" propagation="REQUIRED"/>
            <tx:method name="*remove*" propagation="REQUIRED"/>
            <tx:method name="*drop*" propagation="REQUIRED"/>
            <tx:method name="*clear*" propagation="REQUIRED"/>
            <tx:method name="*" propagation="SUPPORTS"/>
        </tx:attributes>
    </tx:advice>
    <!--绑定切面和切入点-->
    <aop:config>
        <!--切入点表达式-->
        <aop:pointcut id="myCut" expression="execution(* com.sm.service.impl.*.*(..))"/>
        <!--绑定切面和切入点-->
        <aop:advisor advice-ref="maAdvice" pointcut-ref="myCut"/>
    </aop:config>
</beans>

3.spring事务的五大隔离级别

4.为什么添加事务管理器

事务管理器用来生成相应技术的连接+执行语句的对象

如果使用MyBatis框架，必须使用 DataSourceTransactionManager类完成处理

项目中所有的事务必须添加到业务逻辑层上

5.事务的传播特性

多个事务之间的合并、互斥等都可以通过设置事务的传播特性来解决