Spring事务实践
程序员文章站
2022-05-03 08:18:05
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大家都知晓的Spring的事物是基于动态机制的，支持CGLIB和JDK动态代理两种。如下所示：
一.CGLIB方式
CGLIB代理无须必须实现接口。
package com.bijian.study.service;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import com.bijian.study.dao.IUserMapper;
import com.bijian.study.model.User;
@Service("userServiceAOP")
public class UserServiceAOP {
private static final Logger log = LoggerFactory.getLogger(UserServiceImpl.class);
@Autowired
private IUserMapper mapper;
@Transactional
public int txUpdateUsersWhenException() { // 事务性
return innerMethod();
}
private int innerMethod() {
User user = new User(1, "Before exception");
int affectedCount = mapper.updateUser(user); // 因后面的异常而回滚
log.info("{} new record was inserted successfully whose id: {}", affectedCount, user.getId());
User user2 = new User(1, "After exception");
int i = 1 / 0; // 抛出运行时异常，事务回滚
int affectedCount2 = mapper.updateUser(user2); // 未执行
log.info("{} new record was inserted successfully whose id: {}", affectedCount2, user.getId());
if (affectedCount == 1 && affectedCount2 == 1) {
return 1;
}
return 0;
}
}
调试发现确实是CglibAop代理，此时事务是生效的。
二.JDK动态代理
package com.bijian.study.service;
public interface UserService {
public int txUpdateUsersWhenException();
}
package com.bijian.study.service;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import com.bijian.study.dao.IUserMapper;
import com.bijian.study.model.User;
@Service("userService")
public class UserServiceImpl implements UserService {
private static final Logger log = LoggerFactory.getLogger(UserServiceImpl.class);
@Autowired
private IUserMapper mapper;
@Transactional
public int txUpdateUsersWhenException() { // 事务性
return innserMethod();
}
private int innserMethod() {
User user = new User(1, "Before exception");
int affectedCount = mapper.updateUser(user); // 因后面的异常而回滚
log.info("{} new record was inserted successfully whose id: {}", affectedCount, user.getId());
User user2 = new User(1, "After exception");
int i = 1 / 0; // 抛出运行时异常，事务回滚
int affectedCount2 = mapper.updateUser(user2); // 未执行
log.info("{} new record was inserted successfully whose id: {}", affectedCount2, user.getId());
if (affectedCount == 1 && affectedCount2 == 1) {
return 1;
}
return 0;
}
}
调试发现确实是JDK动态代理，此时事务是生效的。
三.测试代码
package com.bijian.study.test;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.bijian.study.service.UserService;
import com.bijian.study.service.UserServiceAOP;
public class SpringIntegrationTest {
private static ApplicationContext ctx;
static {
ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
}
@Test
public void txUpdateUsersExceptionTest() {
UserService userService = (UserService) ctx.getBean("userService");
userService.txUpdateUsersWhenException();
}
@Test
public void txUpdateUsersExceptionAOPTest() {
UserServiceAOP userServiceAOP = (UserServiceAOP) ctx.getBean("userServiceAOP");
userServiceAOP.txUpdateUsersWhenException();
}
}
applicationContext.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:p="http://www.springframework.org/schema/p"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:tx="http://www.springframework.org/schema/tx"
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">
<!-- 数据库配置文件 -->
<context:property-placeholder location="classpath:/database.properties" />
<!-- 数据源配置 -->
<!--本示例采用DBCP连接池，应预先把DBCP的jar包复制到工程的lib目录下。 -->
<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"
p:driverClassName="${driverClassName}" p:url="${url}" p:username="${user_name}"
p:password="${password}" />
<!-- sqlSessionFactory对象 -->
<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<!--dataSource属性指定要用到的连接池 -->
<property name="dataSource" ref="dataSource" />
<!--configLocation属性指定mybatis的核心配置文件 -->
<property name="configLocation" value="classpath:Configuration.xml" />
<!-- 可以在Configuration.xml或此处配置映射文件，但其中不能有相同id的parameterMap, resultMap或sql等 -->
<property name="mapperLocations" value="classpath*:com/bijian/study/model/*.xml" />
</bean>
<!-- 扫描指定包以获取映射器 -->
<bean id="mapperConfigurer" class="org.mybatis.spring.mapper.MapperScannerConfigurer">
<property name="basePackage" value="com.bijian.study.dao" />
</bean>
<!-- 事务管理器 -->
<bean id="txManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<property name="dataSource" ref="dataSource" />
</bean>
<!-- 事务注解驱动，标注@Transactional的类和方法将具有事务性 -->
<tx:annotation-driven transaction-manager="txManager" />
<bean id="userService" class="com.bijian.study.service.UserServiceImpl" />
<bean id="userServiceAOP" class="com.bijian.study.service.UserServiceAOP" />
<bean id="txTemplate" class="org.springframework.transaction.support.TransactionTemplate">
<constructor-arg type="org.springframework.transaction.PlatformTransactionManager" ref="txManager" />
</bean>
</beans>
database.properties
driverClassName=com.mysql.jdbc.Driver url=jdbc:mysql://192.168.235.1:3306/hbatis?characterEncoding=utf8 user_name=bijian password=123456
四.将@Transactional放到非外部直接调用的方法上
将@Transactional放到非外部直接调用的方法上，调试发现无代理，事务失效。
1.修改CGLIB方式的服务方法
package com.bijian.study.service;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import com.bijian.study.dao.IUserMapper;
import com.bijian.study.model.User;
@Service("userServiceAOP")
public class UserServiceAOP {
private static final Logger log = LoggerFactory.getLogger(UserServiceImpl.class);
@Autowired
private IUserMapper mapper;
public int txUpdateUsersWhenException() { // 事务性
return innerMethod();
}
@Transactional
private int innerMethod() {
User user = new User(1, "Before exception");
int affectedCount = mapper.updateUser(user); // 因后面的异常而回滚
log.info("{} new record was inserted successfully whose id: {}", affectedCount, user.getId());
User user2 = new User(1, "After exception");
int i = 1 / 0; // 抛出运行时异常，事务回滚
int affectedCount2 = mapper.updateUser(user2); // 未执行
log.info("{} new record was inserted successfully whose id: {}", affectedCount2, user.getId());
if (affectedCount == 1 && affectedCount2 == 1) {
return 1;
}
return 0;
}
}
@Transactional方法不是服务类的入口方法，无CGLIB代理，事务失效。
2.修改JDK动态代理方式的服务方法
package com.bijian.study.service;
public interface UserService {
public int txUpdateUsersWhenException();
}
package com.bijian.study.service;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import com.bijian.study.dao.IUserMapper;
import com.bijian.study.model.User;
@Service("userService")
public class UserServiceImpl implements UserService {
private static final Logger log = LoggerFactory.getLogger(UserServiceImpl.class);
@Autowired
private IUserMapper mapper;
public int txUpdateUsersWhenException() { // 事务性
return innserMethod();
}
@Transactional
private int innserMethod() {
User user = new User(1, "Before exception");
int affectedCount = mapper.updateUser(user); // 因后面的异常而回滚
log.info("{} new record was inserted successfully whose id: {}", affectedCount, user.getId());
User user2 = new User(1, "After exception");
int i = 1 / 0; // 抛出运行时异常，事务回滚
int affectedCount2 = mapper.updateUser(user2); // 未执行
log.info("{} new record was inserted successfully whose id: {}", affectedCount2, user.getId());
if (affectedCount == 1 && affectedCount2 == 1) {
return 1;
}
return 0;
}
}
@Transactional方法不是服务类的入口方法，无JDK动态代理，事务失效。
测试前数据库中user表数据如下：
mysql> select * from user; +----+--------+------+-------------------+ | id | name | age | address | +----+--------+------+-------------------+ | 1 | bijian | 120 | hangzhou,westlake | +----+--------+------+-------------------+ 1 row in set (0.00 sec)
测试方法的innserMethod中虽然抛出异常，但事务并没有回滚，测试后数据库中user表数据如下：
mysql> select * from user; +----+------+------+------------------+ | id | name | age | address | +----+------+------+------------------+ | 1 | NULL | 0 | Before exception | +----+------+------+------------------+ 1 row in set (0.00 sec)
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