spring事务管理之四：声明式事务管理：使用事务注解的方式

迈不过友情╰ 2022-04-08 14:22 239阅读 0赞

事务注解的方式，相对xml的方式来说，有优点，无需配置需要事务的业务方法的切点和事务属性。但是也有缺点，就是需要在每个需要事务的业务方法上加上一个注解@Transaction，否则事务不会生效。

这里沿用之前spring事务管理的代码：

pom.xml依赖部分：

<dependencies>
        <dependency>
          	<groupId>junit</groupId>
          	<artifactId>junit</artifactId>
          	<version>4.12</version>
          	<scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.aspectj</groupId>
        	<artifactId>aspectjweaver</artifactId>
        	<version>1.8.13</version>
        </dependency>
        <dependency>
        	<groupId>org.springframework</groupId>
        	<artifactId>spring-context-support</artifactId>
        	<version>4.3.4.RELEASE</version>
        </dependency>
        <dependency>
        	<groupId>org.springframework</groupId>
        	<artifactId>spring-tx</artifactId>
        	<version>4.3.4.RELEASE</version>
        </dependency>
        <dependency>
        	<groupId>org.springframework</groupId>
        	<artifactId>spring-jdbc</artifactId>
        	<version>4.3.4.RELEASE</version>
        </dependency>
        <dependency>
        	<groupId>org.springframework</groupId>
        	<artifactId>spring-test</artifactId>
        	<version>4.3.4.RELEASE</version>
        </dependency>
        <dependency>
        	<groupId>mysql</groupId>
        	<artifactId>mysql-connector-java</artifactId>
        	<version>5.1.38</version>
        </dependency>
      </dependencies>

jdbc.properties

jdbc.driverClassName=com.mysql.jdbc.Driver
    jdbc.url=jdbc:mysql:///shop?useUnicode=true&useSSL=false
    jdbc.username=hadoop
    jdbc.password=hadoop

spring.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: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-4.3.xsd
    		http://www.springframework.org/schema/context 
            http://www.springframework.org/schema/context/spring-context-4.3.xsd
    		http://www.springframework.org/schema/aop 
            http://www.springframework.org/schema/aop/spring-aop-4.3.xsd
    		http://www.springframework.org/schema/tx 
            http://www.springframework.org/schema/tx/spring-tx-4.3.xsd">
        <context:property-placeholder location="classpath:jdbc.properties"/>
        <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
           <property name="driverClassName" value="${jdbc.driverClassName}"/>
           <property name="url" value="${jdbc.url}"/>
           <property name="username" value="${jdbc.username}"/>
           <property name="password" value="${jdbc.password}"/>
        </bean>
        <bean id="accountDao" class="com.xxx.springtransaction.dao.impl.AccountDaoImpl">
        	<property name="dataSource" ref="dataSource"/>
        </bean>
        <bean id="accountService" class="com.xxx.springtransaction.service.impl.AccountServiceImpl">
            <property name="accountDao" ref="accountDao"></property>
        </bean>
        <bean id="transactionManager" class="org.springframework.jdbc.datasource
          .DataSourceTransactionManager">
            <property name="dataSource" ref="dataSource" />
        </bean>
        
        <tx:annotation-driven transaction-manager="transactionManager"/>
    </beans>

AccountDao.java

package com.xxx.springtransaction.dao;
    
    public interface AccountDao {
    	public void transferIn(String id,Double money);
    	public void transferOut(String id,Double money);
    	public Double findById(String id);
    }

AccountDaoImpl.java

package com.xxx.springtransaction.dao.impl;
    import org.springframework.jdbc.core.support.JdbcDaoSupport;
    import com.xxx.springtransaction.dao.AccountDao;
    public class AccountDaoImpl extends JdbcDaoSupport implements AccountDao {	
    
    	@Override
    	public void transferIn(String id, Double money) {
    		String sql = "update account set money = money + ? where id = ?";
    		getJdbcTemplate().update(sql, money,id);
    	}
    
    	@Override
    	public void transferOut(String id, Double money) {
    		String sql = "update account set money = money - ? where id = ?";
    		getJdbcTemplate().update(sql, money,id);
    	}
    	
    	@Override
    	public Double findById(String id){
    		return null;
    	}
    
    }

AccountService.java

package com.xxx.springtransaction.service;
    
    public interface AccountService {
    	public void transfer(String out,String in,Double money);
    	public Double findById(String id);
    }

AccountServiceImpl.java

package com.xxx.springtransaction.service.impl;
    import org.springframework.transaction.TransactionStatus;
    import org.springframework.transaction.annotation.Transactional;
    import com.xxx.springtransaction.dao.AccountDao;
    import com.xxx.springtransaction.service.AccountService;
    @Transactional
    public class AccountServiceImpl implements AccountService {
    	
    	private AccountDao accountDao;
    	public void setAccountDao(AccountDao accountDao) {
    		this.accountDao = accountDao;
    	}
    	@Override
    	public void transfer(String out, String in, Double money) {	
    		accountDao.transferOut(out, money);
    		//int i = 1/0;
    		//System.out.println(i);
    		accountDao.transferIn(in, money);
    	}
    	
    	@Override
    	public Double findById(String id){
    		return accountDao.findById(id);
    	}
    
    }

测试类：

package com.xxx.springtransaction;
    import javax.annotation.Resource;
    import org.junit.Test;
    import org.junit.runner.RunWith;
    import org.springframework.test.context.ContextConfiguration;
    import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
    import com.xxx.springtransaction.service.AccountService;
    
    @RunWith(SpringJUnit4ClassRunner.class)
    @ContextConfiguration("classpath:spring.xml")
    public class SpringTransactionTest {
    	@Resource
    	private AccountService accountService;
    	
    	@Test
    	public void demo1(){
    		accountService.transfer("1", "2", 200d);
    	}
    }

注解式事务管理的重点是：启用事务注解驱动和在业务类中添加事务注解@Transactional

<tx:annotation-transaction transaction-manager="transactionManager"/>

@Transactional

第一次测试，不使用事务，我们将AccountServiceImpl.java中的导致异常的两行代码注释掉，并且注释@Transactional，然后测试转账，发现是可以成功的。aaa给bbb转账200元，最后aaa的账户800元，bbb的账户1200元。

第二次测试，我们将AccountServiceImpl.java中的导致异常的两行代码去掉注释，然后测试转账，发现是不能全部成功。aaa给bbb转账200元，最后aaa的账户600元，bbb的账户还是1200元，钱转丢了。

第三次测试，将第一次测试中，业务层注释的事务注解@Transactional打开，再次测试转账，aaa向bbb转账200元，结果因为异常，aaa的账户还是600元，bbb的账户还是1200元，没有发生第二步中的钱转丢的情况，因为异常情况下，事务回滚了。所以转账操作一个也没有成功，说明注解式事务生效了。

对于spring事务管理而言，如果是springmvc的项目，倾向于使用xml配置的方式，如果是springboot了，只能使用注解的方式。