基于AOP的事务管理
使用转账的例子来说明基于AOP的事务管理
1.导入jar包
2.创建数据库
/* Navicat MySQL Data Transfer Source Server : localhost Source Server Version : 50725 Source Host : localhost:3306 Source Database : springtx Target Server Type : MYSQL Target Server Version : 50725 File Encoding : 65001 Date: 2019-03-28 16:54:21 */ SET FOREIGN_KEY_CHECKS=0; -- ---------------------------- -- Table structure for account -- ---------------------------- DROP TABLE IF EXISTS `account`; CREATE TABLE `account` ( `id` int(11) NOT NULL AUTO_INCREMENT, `username` varchar(50) DEFAULT NULL, `money` int(11) DEFAULT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=latin1; -- ---------------------------- -- Records of account -- ---------------------------- INSERT INTO `account` VALUES ('1', 'xiaoming', '10000'); INSERT INTO `account` VALUES ('2', 'xiaohong', '10000');
3.编写dao层的代码
package oyb.dao; public interface IAccountDao { public void out(String outer, Integer money); public void in(String inner, Integer money); }
package oyb.dao.impl; import org.springframework.jdbc.core.support.JdbcDaoSupport; import oyb.dao.IAccountDao; public class AccountDaoImpl extends JdbcDaoSupport implements IAccountDao { @Override public void out(String outer, Integer money) { String sql = "update account set money = money - ? where username = ?"; this.getJdbcTemplate().update(sql,money,outer); } @Override public void in(String inner, Integer money) { String sql = "update account set money = money + ? where username = ?"; this.getJdbcTemplate().update(sql,money,inner); } }
4.编写业务层的代码
package oyb.service; public interface IAccountService { public void transfer(String outer, String in, Integer money); }
package oyb.service.impl; import oyb.dao.IAccountDao; import oyb.service.IAccountService; public class AccountServiceImpl implements IAccountService { //提供set方法，由spring注入 private IAccountDao accountDao; public void setAccountDao(IAccountDao accountDao) { this.accountDao = accountDao; } @Override public void transfer(String outer, String inner, Integer money) { accountDao.out(outer,money); accountDao.in(inner,money); } }
添加db.properties文件
driverClass=com.mysql.jdbc.Driver jdbcUrl=jdbc:mysql:///springtx user=root password=123456
配置beans.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:p="http://www.springframework.org/schema/p" xmlns:context="http://www.springframework.org/schema/context" xmlns:aop="http://www.springframework.org/schema/aop" 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 http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd"> <!--读取db.properties数据--> <context:property-placeholder location="classpath:db.properties"></context:property-placeholder> <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"> <property name="driverClass" value="${driverClass}"/> <property name="jdbcUrl" value="${jdbcUrl}"/> <property name="user" value="${user}"/> <property name="password" value="${password}"/> </bean> <!--配置dao--> <bean id="accountDao" class="oyb.dao.impl.AccountDaoImpl"> <!--注入属性--> <property name="dataSource" ref="dataSource"></property> </bean> <!--配置service--> <bean id="accountService" class="oyb.service.impl.AccountServiceImpl"> <property name="accountDao" ref="accountDao"></property> </bean> </beans>
测试转账功能是否完好
import org.junit.Test; import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; import oyb.dao.IAccountDao; import oyb.service.IAccountService; public class test { @Test public void test(){ ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml"); IAccountService accountService = (IAccountService) context.getBean("accountService"); accountService.transfer("xiaoming","xiaohong",100); } }
测试的结果
基本的条件搭建好了之后，下面来讲基于AOP的事务配置，除了AOP的自动代理，还有工厂代理以及手动管理事务，后两者可作为了解，这里不涉及，主要还是掌握基于AOP的事务管理。
在配置事务管理前，我们可以看下如果业务类中的transfer方法出现了异常，数据库的结果会是怎样的。
我在转账的方法中加了一句int i = 10/0 这段会抛出异常的代码
可执行完测试的代码之后可以发现，xiaoming的钱虽然减少了，但是并未转入xiaohong的账户中，根据事务管理可知，如果出现了异常，应该回滚。
以上便是没有配置事务管理所会出现的结果
我们让xiaoming的账户恢复到之前的余额
修改beans.xml这个配置文件
<?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:p="http://www.springframework.org/schema/p" xmlns:context="http://www.springframework.org/schema/context" xmlns:aop="http://www.springframework.org/schema/aop" 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 http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd"> <!--读取db.properties数据--> <context:property-placeholder location="classpath:db.properties"></context:property-placeholder> <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"> <property name="driverClass" value="${driverClass}"/> <property name="jdbcUrl" value="${jdbcUrl}"/> <property name="user" value="${user}"/> <property name="password" value="${password}"/> </bean> <!--配置dao--> <bean id="accountDao" class="oyb.dao.impl.AccountDaoImpl"> <!--注入属性--> <property name="dataSource" ref="dataSource"></property> </bean> <!--配置service--> <bean id="accountService" class="oyb.service.impl.AccountServiceImpl"> <property name="accountDao" ref="accountDao"></property> </bean> <!--配置jdbc事务管理器--> <bean id="txManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager"> <property name="dataSource" ref="dataSource"></property> </bean> <!--AOP的事务配置--> <!--1.配置通知 tx:attributes:配置事务的传播行为以及隔离级别
隔离级别配置成默认的即可，传播行为也使用默认的required --> <tx:advice id="txAdvice" transaction-manager="txManager"> <tx:attributes> <tx:method name="transfer" isolation="DEFAULT" propagation="REQUIRED"/> </tx:attributes> </tx:advice> <!--配置切面--> <aop:config> <aop:advisor advice-ref="txAdvice" pointcut="execution(* oyb.service..*.*(..))"></aop:advisor> </aop:config> </beans>
此时在transfer方法中还有int 10/0 这段代码，所以仍存在异常，运行完测试类后，我们查看下数据库
可知事务确实是回滚了。
我们把int i =10/0这句代码删除，在运行测试方法查看下数据库
以上便是基于AOP的事务配置的例子
