SpringBoot_事务总结
Springboot 事务
1. 打印SQL 日志的两种配置方式
[1]通过配置包的log等级来打印SQL日志，但这种不会打印出事务日志
logging.level.com.grady.mybatisdemo.mapper=DEBUG
[2] 配置mybatis的logImpl属性，好处是会输出事务日志
mybatis.configuration.logImpl=org.apache.ibatis.logging.stdout.StdOutImpl
PS：rollbackFor默认是非受检异常回滚，配置rollbackFor = Exception.class改成所有异常回滚
2 成功和失败的日志信息
[1]. 一次查询成功的日志
代码
@Transactional(rollbackFor = Exception.class)
@PostMapping("/allUser")
public PageInfo<User> allUser() {
PageHelper.startPage(2,3);
List<User> users = userMapper.findAllUser();
PageInfo<User> pageInfo = new PageInfo<>(users);
return pageInfo;
}
Creating a new SqlSession
Registering transaction synchronization for SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@7580f2b1]
Cache Hit Ratio [SQL_CACHE]: 0.5
JDBC Connection [HikariProxyConnection@2138610113 wrapping com.mysql.cj.jdbc.ConnectionImpl@55855042] will be managed by Spring
==> Preparing: SELECT count(0) FROM user_copy
==> Parameters:
<== Columns: count(0)
<== Row: 5
<== Total: 1
==> Preparing: SELECT * FROM user_copy LIMIT ?, ?
==> Parameters: 3(Integer), 3(Integer)
<== Columns: user_id, name, password, token, ownapps, role_id
<== Row: 4, testUser4, 4, a, 2, 4
<== Row: 5, testUser5, 5, a, 4, 5
<== Total: 2
Releasing transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@7580f2b1]
Transaction synchronization committing SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@7580f2b1]
Transaction synchronization deregistering SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@7580f2b1]
Transaction synchronization closing SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@7580f2b1]
[2]. 一次抛异常回滚的日志
代码：
@Transactional(rollbackFor = Exception.class)
@Override
public Integer insertUser(User user) throws BusinessException {
try {
List<User> users = userMapper.findAllUser();
Integer result = userMapper.insert(user);
if (true) {
int i = 1 / 0; //这里抛RuntimeException异常
}
return result;
} catch (Exception e) {
e.printStackTrace();
throw new BusinessException("访问数据库失败", 1001);// 被我catch然后改为受检异常抛出
}
}
Creating a new SqlSession
Registering transaction synchronization for SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@2e775383]
JDBC Connection [HikariProxyConnection@1016081606 wrapping com.mysql.cj.jdbc.ConnectionImpl@3560cd99] will be managed by Spring
==> Preparing: SELECT * FROM user_copy
==> Parameters:
<== Columns: user_id, name, password, token, ownapps, role_id
<== Row: 1, testUser1, 1, a, 2, 1
<== Row: 2, testUser2, 2, a, 2, 2
<== Row: 3, testUser3, 3, a, 2, 3
<== Row: 4, testUser4, 4, a, 2, 4
<== Row: 5, testUser5, 5, a, 4, 5
<== Total: 5
Releasing transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@2e775383]
Fetched SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@2e775383] from current transaction
==> Preparing: INSERT INTO user_copy ( name, password, token, ownapps, role_id ) VALUES ( ?, ?, ?, ?, ? )
==> Parameters: jiang(String), zhongjin(String), abcd(String), o(String), 2(Long)
<== Updates: 1
Releasing transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@2e775383]
Transaction synchronization deregistering SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@2e775383]
Transaction synchronization closing SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@2e775383]
ps：此异常从被Transactional注解的方法中抛出后就立即回滚并关闭SQLSession了
总结1：SpringBoot使用事务就是这么容易，只要在对应的方法上加上注解就可以了
3. 事务冲突问题
当使用事务增强来为一些匹配的方法加上事务，如果在这些方法调用其他被@Transactional绑定的方法时，会抛出事务异常，但对数据不会有影响**
比如：
事务增强加在了Controller上，controller调用Manager的方法，而Manager方式使用了@Transactional注解，这是会抛一下错误（经测试如果加载controller自己上没有问题，在调用链上才有问题）
抛出的异常是
org.springframework.transaction.UnexpectedRollbackException: Transaction rolled back because it has been marked as rollback-only
at org.springframework.transaction.support.AbstractPlatformTransactionManager.processRollback(AbstractPlatformTransactionManager.java:873) ~[spring-tx-5.1.9.RELEASE.jar:5.1.9.RELEASE]
at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:710) ~[spring-tx-5.1.9.RELEASE.jar:5.1.9.RELEASE]
[1] 使用事务增强的两种方式
①XML 方式(然后使用@ImportResource("classpath:transaction.xml")引入)
<?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: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/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">
<bean id="txManager"
class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<property name="dataSource" ref="dataSource" ></property>
</bean>
<tx:advice id="cftxAdvice" transaction-manager="txManager">
<tx:attributes>
<tx:method name="query*" propagation="SUPPORTS" read-only="true" ></tx:method>
<tx:method name="get*" propagation="SUPPORTS" read-only="true" ></tx:method>
<tx:method name="select*" propagation="SUPPORTS" read-only="true" ></tx:method>
<tx:method name="*" propagation="REQUIRED" rollback-for="Exception" ></tx:method>
</tx:attributes>
</tx:advice>
<aop:config>
<aop:pointcut id="allManagerMethod" expression="execution (* com.grady.mybatisdemo..controller.*.*(..))" />
<aop:advisor advice-ref="txAdvice" pointcut-ref="allManagerMethod" order="0" />
</aop:config>
</beans>
// read-only="true" 表示这个方法只能读数据库，写会报错
这个增强表示，controller下的所有方法都在范围内，如果满足tx:method 的条件则加上事务
②代码配置方式
@Configuration
public class TransactionAdviceConfig {
private static final String AOP_POINTCUT_EXPRESSION = "execution (* com.grady.mybatisdemo..controller.*.*(..))";
@Autowired
private PlatformTransactionManager transactionManager;
@Bean(name = "txAdvice")
public TransactionInterceptor txAdvice() {
Properties properties = new Properties();
// readOnly 表示这个方法只能读数据库，写会报错
properties.setProperty("get*", "PROPAGATION_REQUIRED,-Exception,readOnly");
properties.setProperty("add*", "PROPAGATION_REQUIRED,-Exception");
properties.setProperty("save*", "PROPAGATION_REQUIRED,-Exception");
properties.setProperty("update*", "PROPAGATION_REQUIRED,-Exception");
properties.setProperty("delete*", "PROPAGATION_REQUIRED,-Exception");
//"PROPAGATION_REQUIRED, -Exception"这里有空格不要紧
properties.setProperty("insert*", "PROPAGATION_REQUIRED,-Exception");
TransactionInterceptor transactionInterceptor = new TransactionInterceptor(transactionManager, properties);
return transactionInterceptor;
}
@Bean
public Advisor txAdviceAdvisor() {
AspectJExpressionPointcut pointcut = new AspectJExpressionPointcut();
pointcut.setExpression(AOP_POINTCUT_EXPRESSION);
return new DefaultPointcutAdvisor(pointcut, txAdvice());
}
}
经测试 properties.setProperty("insert*", "PROPAGATION_REQUIRED,-Exception"); "PROPAGATION_REQUIRED,-Exception" 每个关键字的两侧有空格不要紧，加载前会自动trim
代码的方式要更加优雅，可以利用到编译器在编译期做检查，XML只有运行时才能知道是对是错，代码的方式相对会更好一些
总结：
-
建议不要使用事务增强，因为你还得去记哪些方法名会被加事务，哪些不会，也会影响到你对方法的命名，一个表意的函数名是非常重要的，我觉得这种方式是得不偿失的。
-
建议直接使用@Transactional 来为方法加事务，这样一眼就可以知道当前方法有没有事务。
-
最好不要用了事务增强，又用@Transactional，因为如果两个方法加在了同一个方法链上，一旦抛异常回滚是会报UnexpectedRollbackException异常错误的
-
如果在调用链很后的地方抛出的异常，到被事务增强的函数时，此时一定要接着抛出，否则不会回滚，因为内部消化的异常等于正常操作，不会回滚
