摘抄概念如下：
Spring在TransactionDefinition接口中规定了7种类型的事务传播行为，它们规定了事务方法和事务方法发生嵌套调用时事务如何进行传播：
表1事务传播行为类型
| 事务传播行为类型 |
说明 |
| PROPAGATION_REQUIRED |
如果当前没有事务，就新建一个事务，如果已经存在一个事务中，加入到这个事务中。这是最常见的选择。spring默认使用此传播类型 |
| PROPAGATION_SUPPORTS |
支持当前事务，如果当前没有事务，就以非事务方式执行。 |
| PROPAGATION_MANDATORY |
使用当前的事务，如果当前没有事务，就抛出异常。 |
| PROPAGATION_REQUIRES_NEW |
新建事务，如果当前存在事务，把当前事务挂起。 |
| PROPAGATION_NOT_SUPPORTED |
以非事务方式执行操作，如果当前存在事务，就把当前事务挂起。 |
| PROPAGATION_NEVER |
以非事务方式执行，如果当前存在事务，则抛出异常。 |
| PROPAGATION_NESTED |
如果当前存在事务，则在嵌套事务内执行。如果当前没有事务，则执行与PROPAGATION_REQUIRED类似的操作。 |
当使用PROPAGATION_NESTED时，底层的数据源必须基于JDBC 3.0，并且实现者需要支持保存点事务机制
Spring 默认的事务传播行为是 PROPAGATION_REQUIRED，它适合于绝大多数的情况。假设 ServiveX#methodX() 都工作在事务环境下（即都被 Spring 事务增强了），假设程序中存在如下的调用链：Service1#method1()->Service2#method2()->Service3#method3()，那么这 3 个服务类的 3 个方法通过 Spring 的事务传播机制都工作在同一个事务中。
通过阅读Spring3.X企业开发实战书籍，回顾了一下事务传播的相关知识点，并通过小实验来加深印象。
实验如下：
由controller调用service，且包含不同service之间调用，日志启用DEBUG级别
事务传播方式采用默认：PROPAGATION_REQUIRED
隔离级别采用默认：
1：
@RequestMapping(value="/test")
public void insert() {
System.out.println("---------spring mvc update---------");
userService.update(111,"aaaazz");
System.out.println("---------spring mvc all---------");
}2：UserServiceImpl的update方法：
@Override
@Transactional
public void update(int id,String username) {
System.out.println("---------UserServiceImpl updateAge start---------");
updateAge(id);
System.out.println("---------UserServiceImpl updateAge end---------");
System.out.println("---------scoreService updateScore start---------");
scoreService.updateScore(id);
System.out.println("---------scoreService updateScore end---------");
// int i = 1 / 0; //exception测试注释
}3：ScopeService的updateScore方法：
@Override
@Transactional
public void updateScore(int id) {
scoreDao.updateScore(id);
// int i = 1 / 0; //exception测试注释
}实例1：
UserServiceImpl#update和ScoreService#updateScore都开启事务注解，输出日志：
---------spring mvc update---------
[DEBUG] 2018-05-21 15:20:31,931 method:org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:243)
Returning cached instance of singleton bean 'org.springframework.transaction.interceptor.TransactionInterceptor#0'
[DEBUG] 2018-05-21 15:20:31,938 method:org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:243)
Returning cached instance of singleton bean 'transactionManager'
[DEBUG] 2018-05-21 15:20:31,947 method:org.springframework.transaction.support.AbstractPlatformTransactionManager.getTransaction(AbstractPlatformTransactionManager.java:366)
Creating new transaction with name [com.paic.ssm.user.service.impl.UserServiceImpl.update]: PROPAGATION_REQUIRED,ISOLATION_DEFAULT; ''
[DEBUG] 2018-05-21 15:20:31,948 method:org.springframework.jdbc.datasource.DataSourceTransactionManager.doBegin(DataSourceTransactionManager.java:204)
Acquired Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@8de40e] for JDBC transaction
[DEBUG] 2018-05-21 15:20:31,956 method:org.springframework.jdbc.datasource.DataSourceTransactionManager.doBegin(DataSourceTransactionManager.java:221)
Switching JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@8de40e] to manual commit
---------UserServiceImpl updateAge start---------
15:20:31.965 [http-bio-8080-exec-1] DEBUG org.mybatis.spring.SqlSessionUtils - Creating a new SqlSession
15:20:31.973 [http-bio-8080-exec-1] DEBUG org.mybatis.spring.SqlSessionUtils - Registering transaction synchronization for SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@1e45c4f]
15:20:32.030 [http-bio-8080-exec-1] DEBUG o.m.s.t.SpringManagedTransaction - JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@8de40e] will be managed by Spring
15:20:32.033 [http-bio-8080-exec-1] DEBUG c.p.ssm.user.dao.IUserDao.updateAge - ooo Using Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@8de40e]
15:20:32.039 [http-bio-8080-exec-1] DEBUG c.p.ssm.user.dao.IUserDao.updateAge - ==> Preparing: update user_t set age = ?
15:20:32.182 [http-bio-8080-exec-1] DEBUG c.p.ssm.user.dao.IUserDao.updateAge - ==> Parameters: 111(Integer)
[DEBUG] 2018-05-21 15:20:32,186 method:com.alibaba.druid.pool.PreparedStatementPool.put(PreparedStatementPool.java:123)
{conn-10010, pstmt-20000} enter cache
15:20:32.187 [http-bio-8080-exec-1] DEBUG org.mybatis.spring.SqlSessionUtils - Releasing transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@1e45c4f]
---------UserServiceImpl updateAge end---------
---------scoreService updateScore start---------
[DEBUG] 2018-05-21 15:20:32,187 method:org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:243)
Returning cached instance of singleton bean 'transactionManager'
[DEBUG] 2018-05-21 15:20:32,188 method:org.springframework.transaction.support.AbstractPlatformTransactionManager.handleExistingTransaction(AbstractPlatformTransactionManager.java:471)
Participating in existing transaction
15:20:32.188 [http-bio-8080-exec-1] DEBUG org.mybatis.spring.SqlSessionUtils - Fetched SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@1e45c4f] from current transaction
15:20:32.189 [http-bio-8080-exec-1] DEBUG c.p.s.user.dao.IScoreDao.updateScore - ooo Using Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@8de40e]
15:20:32.189 [http-bio-8080-exec-1] DEBUG c.p.s.user.dao.IScoreDao.updateScore - ==> Preparing: update score_t set score = ?
15:20:32.189 [http-bio-8080-exec-1] DEBUG c.p.s.user.dao.IScoreDao.updateScore - ==> Parameters: 111(Integer)
[DEBUG] 2018-05-21 15:20:32,254 method:com.alibaba.druid.pool.PreparedStatementPool.put(PreparedStatementPool.java:123)
{conn-10010, pstmt-20001} enter cache
15:20:32.256 [http-bio-8080-exec-1] DEBUG org.mybatis.spring.SqlSessionUtils - Releasing transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@1e45c4f]
---------scoreService updateScore end---------
[DEBUG] 2018-05-21 15:20:32,257 method:org.springframework.transaction.support.AbstractPlatformTransactionManager.processCommit(AbstractPlatformTransactionManager.java:753)
Initiating transaction commit
[DEBUG] 2018-05-21 15:20:32,258 method:org.springframework.jdbc.datasource.DataSourceTransactionManager.doCommit(DataSourceTransactionManager.java:267)
Committing JDBC transaction on Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@8de40e]
15:20:32.321 [http-bio-8080-exec-1] DEBUG org.mybatis.spring.SqlSessionUtils - Transaction synchronization committing SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@1e45c4f]
15:20:32.321 [http-bio-8080-exec-1] DEBUG org.mybatis.spring.SqlSessionUtils - Transaction synchronization closing SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@1e45c4f]
[DEBUG] 2018-05-21 15:20:32,322 method:org.springframework.jdbc.datasource.DataSourceTransactionManager.doCleanupAfterCompletion(DataSourceTransactionManager.java:325)
Releasing JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@8de40e] after transaction
[DEBUG] 2018-05-21 15:20:32,324 method:org.springframework.jdbc.datasource.DataSourceUtils.doReleaseConnection(DataSourceUtils.java:327)
Returning JDBC Connection to DataSource
---------spring mvc all---------
可以看到，在userServcie执行update之前，spring创建了一个事务：
Creating new transaction with name。。。
执行完毕之后，再执行scoreService的updateScore之前，并未创建新的事务，而是参与到了已存在的事务中：
Participating in existing transaction。。。
最终提交此事务：
Committing JDBC transaction on Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@8de40e]
说明，不同service之间调用时，若两者都存在事务，则后者不会自省创建事务，而是参与到之前的事务中
2：UserServiceImpl#update开启事务，ScoreService#updateScore不开启事务，输出日志：
---------spring mvc update---------
[DEBUG] 2018-05-21 15:21:32,255 method:org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:243)
Returning cached instance of singleton bean 'org.springframework.transaction.interceptor.TransactionInterceptor#0'
[DEBUG] 2018-05-21 15:21:32,263 method:org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:243)
Returning cached instance of singleton bean 'transactionManager'
[DEBUG] 2018-05-21 15:21:32,273 method:org.springframework.transaction.support.AbstractPlatformTransactionManager.getTransaction(AbstractPlatformTransactionManager.java:366)
Creating new transaction with name [com.paic.ssm.user.service.impl.UserServiceImpl.update]: PROPAGATION_REQUIRED,ISOLATION_DEFAULT; ''
[DEBUG] 2018-05-21 15:21:32,273 method:org.springframework.jdbc.datasource.DataSourceTransactionManager.doBegin(DataSourceTransactionManager.java:204)
Acquired Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@9d935d] for JDBC transaction
[DEBUG] 2018-05-21 15:21:32,280 method:org.springframework.jdbc.datasource.DataSourceTransactionManager.doBegin(DataSourceTransactionManager.java:221)
Switching JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@9d935d] to manual commit
---------UserServiceImpl updateAge start---------
15:21:32.289 [http-bio-8080-exec-3] DEBUG org.mybatis.spring.SqlSessionUtils - Creating a new SqlSession
15:21:32.296 [http-bio-8080-exec-3] DEBUG org.mybatis.spring.SqlSessionUtils - Registering transaction synchronization for SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@d92da1]
15:21:32.354 [http-bio-8080-exec-3] DEBUG o.m.s.t.SpringManagedTransaction - JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@9d935d] will be managed by Spring
15:21:32.356 [http-bio-8080-exec-3] DEBUG c.p.ssm.user.dao.IUserDao.updateAge - ooo Using Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@9d935d]
15:21:32.361 [http-bio-8080-exec-3] DEBUG c.p.ssm.user.dao.IUserDao.updateAge - ==> Preparing: update user_t set age = ?
15:21:32.502 [http-bio-8080-exec-3] DEBUG c.p.ssm.user.dao.IUserDao.updateAge - ==> Parameters: 111(Integer)
[DEBUG] 2018-05-21 15:21:32,506 method:com.alibaba.druid.pool.PreparedStatementPool.put(PreparedStatementPool.java:123)
{conn-10010, pstmt-20000} enter cache
15:21:32.507 [http-bio-8080-exec-3] DEBUG org.mybatis.spring.SqlSessionUtils - Releasing transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@d92da1]
---------UserServiceImpl updateAge end---------
---------scoreService updateScore start---------
15:21:32.507 [http-bio-8080-exec-3] DEBUG org.mybatis.spring.SqlSessionUtils - Fetched SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@d92da1] from current transaction
15:21:32.507 [http-bio-8080-exec-3] DEBUG c.p.s.user.dao.IScoreDao.updateScore - ooo Using Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@9d935d]
15:21:32.507 [http-bio-8080-exec-3] DEBUG c.p.s.user.dao.IScoreDao.updateScore - ==> Preparing: update score_t set score = ?
15:21:32.508 [http-bio-8080-exec-3] DEBUG c.p.s.user.dao.IScoreDao.updateScore - ==> Parameters: 111(Integer)
[DEBUG] 2018-05-21 15:21:32,586 method:com.alibaba.druid.pool.PreparedStatementPool.put(PreparedStatementPool.java:123)
{conn-10010, pstmt-20001} enter cache
15:21:32.586 [http-bio-8080-exec-3] DEBUG org.mybatis.spring.SqlSessionUtils - Releasing transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@d92da1]
---------scoreService updateScore end---------
[DEBUG] 2018-05-21 15:21:32,587 method:org.springframework.transaction.support.AbstractPlatformTransactionManager.processCommit(AbstractPlatformTransactionManager.java:753)
Initiating transaction commit
[DEBUG] 2018-05-21 15:21:32,587 method:org.springframework.jdbc.datasource.DataSourceTransactionManager.doCommit(DataSourceTransactionManager.java:267)
Committing JDBC transaction on Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@9d935d]
15:21:32.680 [http-bio-8080-exec-3] DEBUG org.mybatis.spring.SqlSessionUtils - Transaction synchronization committing SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@d92da1]
15:21:32.680 [http-bio-8080-exec-3] DEBUG org.mybatis.spring.SqlSessionUtils - Transaction synchronization closing SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@d92da1]
[DEBUG] 2018-05-21 15:21:32,680 method:org.springframework.jdbc.datasource.DataSourceTransactionManager.doCleanupAfterCompletion(DataSourceTransactionManager.java:325)
Releasing JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@9d935d] after transaction
[DEBUG] 2018-05-21 15:21:32,681 method:org.springframework.jdbc.datasource.DataSourceUtils.doReleaseConnection(DataSourceUtils.java:327)
Returning JDBC Connection to DataSource
---------spring mvc all--------- 可以看到，scoreService并未有事务创建和传播的日志，暂无法断定其是否被事务作用
打开userService#update的异常测试代码： int i = 1 / 0;
执行之后，后台报错，部分日志：
17:18:57.650 [http-bio-8080-exec-6] DEBUG org.mybatis.spring.SqlSessionUtils - Releasing transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@1c43375]
---------UserServiceImpl updateAge end---------
---------scoreService updateScore start---------
17:18:57.651 [http-bio-8080-exec-6] DEBUG org.mybatis.spring.SqlSessionUtils - Fetched SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@1c43375] from current transaction
17:18:57.651 [http-bio-8080-exec-6] DEBUG c.p.s.user.dao.IScoreDao.updateScore - ooo Using Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@d6b1dc]
17:18:57.651 [http-bio-8080-exec-6] DEBUG c.p.s.user.dao.IScoreDao.updateScore - ==> Preparing: update score_t set score = ?
17:18:57.651 [http-bio-8080-exec-6] DEBUG c.p.s.user.dao.IScoreDao.updateScore - ==> Parameters: 111(Integer)
[DEBUG] 2018-05-21 17:18:57,652 method:com.alibaba.druid.pool.PreparedStatementPool.put(PreparedStatementPool.java:123)
{conn-10010, pstmt-20001} enter cache
17:18:57.652 [http-bio-8080-exec-6] DEBUG org.mybatis.spring.SqlSessionUtils - Releasing transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@1c43375]
---------scoreService updateScore end---------
[DEBUG] 2018-05-21 17:18:57,653 method:org.springframework.transaction.support.AbstractPlatformTransactionManager.processRollback(AbstractPlatformTransactionManager.java:844)
Initiating transaction rollback
[DEBUG] 2018-05-21 17:18:57,653 method:org.springframework.jdbc.datasource.DataSourceTransactionManager.doRollback(DataSourceTransactionManager.java:282)
Rolling back JDBC transaction on Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@d6b1dc]
17:18:57.827 [http-bio-8080-exec-6] DEBUG org.mybatis.spring.SqlSessionUtils - Transaction synchronization rolling back SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@1c43375]
17:18:57.827 [http-bio-8080-exec-6] DEBUG org.mybatis.spring.SqlSessionUtils - Transaction synchronization closing SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@1c43375]
[DEBUG] 2018-05-21 17:18:57,829 method:org.springframework.jdbc.datasource.DataSourceTransactionManager.doCleanupAfterCompletion(DataSourceTransactionManager.java:325)
Releasing JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@d6b1dc] after transaction
[DEBUG] 2018-05-21 17:18:57,830 method:org.springframework.jdbc.datasource.DataSourceUtils.doReleaseConnection(DataSourceUtils.java:327)
Returning JDBC Connection to DataSource
[DEBUG] 2018-05-21 17:18:57,846 method:org.springframework.web.servlet.handler.AbstractHandlerExceptionResolver.resolveException(AbstractHandlerExceptionResolver.java:132)
Resolving exception from handler [public void com.paic.ssm.login.controller.LoginController.insert()]: java.lang.ArithmeticException: / by zero
[DEBUG] 2018-05-21 17:18:57,850 method:org.springframework.web.servlet.handler.AbstractHandlerExceptionResolver.resolveException(AbstractHandlerExceptionResolver.java:132)
Resolving exception from handler [public void com.paic.ssm.login.controller.LoginController.insert()]: java.lang.ArithmeticException: / by zero
[DEBUG] 2018-05-21 17:18:57,850 method:org.springframework.web.servlet.handler.AbstractHandlerExceptionResolver.resolveException(AbstractHandlerExceptionResolver.java:132)
Resolving exception from handler [public void com.paic.ssm.login.controller.LoginController.insert()]: java.lang.ArithmeticException: / by zero
[DEBUG] 2018-05-21 17:18:57,852 method:org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:974)
Could not complete request
java.lang.ArithmeticException: / by zero
at com.paic.ssm.user.service.impl.UserServiceImpl.update(UserServiceImpl.java:49)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)可以看到，在scoreService执行完毕之后，抛出了异常，日志输出了事务rollback，经查验DB，数据并未修改，说明两个service都被事务作用了，也即事务由userService传播到了scoreService，此时和第一种情况是一样的，无论两者谁抛出异常，只要被初始调用捕获，就会回滚了。
注意：如果scoreService的异常被其本身捕获，那么数据也不会回滚。。。
3：UserServiceImpl#update不开启事务，ScoreService#updateScore开启事务，输出日志：
---------spring mvc update---------
---------UserServiceImpl updateAge start---------
15:27:15.292 [http-bio-8080-exec-8] DEBUG org.mybatis.spring.SqlSessionUtils - Creating a new SqlSession
15:27:15.298 [http-bio-8080-exec-8] DEBUG org.mybatis.spring.SqlSessionUtils - SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@76823b] was not registered for synchronization because synchronization is not active
[DEBUG] 2018-05-21 15:27:15,356 method:org.springframework.jdbc.datasource.DataSourceUtils.doGetConnection(DataSourceUtils.java:110)
Fetching JDBC Connection from DataSource
15:27:15.356 [http-bio-8080-exec-8] DEBUG o.m.s.t.SpringManagedTransaction - JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@c824d8] will not be managed by Spring
15:27:15.358 [http-bio-8080-exec-8] DEBUG c.p.ssm.user.dao.IUserDao.updateAge - ooo Using Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@c824d8]
15:27:15.361 [http-bio-8080-exec-8] DEBUG c.p.ssm.user.dao.IUserDao.updateAge - ==> Preparing: update user_t set age = ?
15:27:15.468 [http-bio-8080-exec-8] DEBUG c.p.ssm.user.dao.IUserDao.updateAge - ==> Parameters: 111(Integer)
[DEBUG] 2018-05-21 15:27:15,505 method:com.alibaba.druid.pool.PreparedStatementPool.put(PreparedStatementPool.java:123)
{conn-10010, pstmt-20000} enter cache
15:27:15.506 [http-bio-8080-exec-8] DEBUG org.mybatis.spring.SqlSessionUtils - Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@76823b]
[DEBUG] 2018-05-21 15:27:15,506 method:org.springframework.jdbc.datasource.DataSourceUtils.doReleaseConnection(DataSourceUtils.java:327)
Returning JDBC Connection to DataSource
---------UserServiceImpl updateAge end---------
---------scoreService updateScore start---------
[DEBUG] 2018-05-21 15:27:15,508 method:org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:243)
Returning cached instance of singleton bean 'org.springframework.transaction.interceptor.TransactionInterceptor#0'
[DEBUG] 2018-05-21 15:27:15,521 method:org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:243)
Returning cached instance of singleton bean 'transactionManager'
[DEBUG] 2018-05-21 15:27:15,526 method:org.springframework.transaction.support.AbstractPlatformTransactionManager.getTransaction(AbstractPlatformTransactionManager.java:366)
Creating new transaction with name [com.paic.ssm.user.service.impl.ScoreServiceImpl.updateScore]: PROPAGATION_REQUIRED,ISOLATION_DEFAULT; ''
[DEBUG] 2018-05-21 15:27:15,527 method:org.springframework.jdbc.datasource.DataSourceTransactionManager.doBegin(DataSourceTransactionManager.java:204)
Acquired Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@c824d8] for JDBC transaction
[DEBUG] 2018-05-21 15:27:15,532 method:org.springframework.jdbc.datasource.DataSourceTransactionManager.doBegin(DataSourceTransactionManager.java:221)
Switching JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@c824d8] to manual commit
15:27:15.534 [http-bio-8080-exec-8] DEBUG org.mybatis.spring.SqlSessionUtils - Creating a new SqlSession
15:27:15.534 [http-bio-8080-exec-8] DEBUG org.mybatis.spring.SqlSessionUtils - Registering transaction synchronization for SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@1d52634]
15:27:15.536 [http-bio-8080-exec-8] DEBUG o.m.s.t.SpringManagedTransaction - JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@c824d8] will be managed by Spring
15:27:15.536 [http-bio-8080-exec-8] DEBUG c.p.s.user.dao.IScoreDao.updateScore - ooo Using Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@c824d8]
15:27:15.536 [http-bio-8080-exec-8] DEBUG c.p.s.user.dao.IScoreDao.updateScore - ==> Preparing: update score_t set score = ?
15:27:15.537 [http-bio-8080-exec-8] DEBUG c.p.s.user.dao.IScoreDao.updateScore - ==> Parameters: 111(Integer)
[DEBUG] 2018-05-21 15:27:15,537 method:com.alibaba.druid.pool.PreparedStatementPool.put(PreparedStatementPool.java:123)
{conn-10010, pstmt-20001} enter cache
15:27:15.538 [http-bio-8080-exec-8] DEBUG org.mybatis.spring.SqlSessionUtils - Releasing transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@1d52634]
[DEBUG] 2018-05-21 15:27:15,538 method:org.springframework.transaction.support.AbstractPlatformTransactionManager.processCommit(AbstractPlatformTransactionManager.java:753)
Initiating transaction commit
[DEBUG] 2018-05-21 15:27:15,538 method:org.springframework.jdbc.datasource.DataSourceTransactionManager.doCommit(DataSourceTransactionManager.java:267)
Committing JDBC transaction on Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@c824d8]
15:27:15.622 [http-bio-8080-exec-8] DEBUG org.mybatis.spring.SqlSessionUtils - Transaction synchronization committing SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@1d52634]
15:27:15.623 [http-bio-8080-exec-8] DEBUG org.mybatis.spring.SqlSessionUtils - Transaction synchronization closing SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@1d52634]
[DEBUG] 2018-05-21 15:27:15,624 method:org.springframework.jdbc.datasource.DataSourceTransactionManager.doCleanupAfterCompletion(DataSourceTransactionManager.java:325)
Releasing JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@c824d8] after transaction
[DEBUG] 2018-05-21 15:27:15,625 method:org.springframework.jdbc.datasource.DataSourceUtils.doReleaseConnection(DataSourceUtils.java:327)
Returning JDBC Connection to DataSource
---------scoreService updateScore end---------
---------spring mvc all--------- 可以看到，userService先执行update，但是并未创建事务，而是直接获取到了connection：
Fetching JDBC Connection from DataSource。。。
而scoreService则开启了事务，并正常commit
有什么影响呢？下面再次打开userService的异常测试代码，执行日志如下：
Initiating transaction commit
[DEBUG] 2018-05-21 17:32:08,784 method:org.springframework.jdbc.datasource.DataSourceTransactionManager.doCommit(DataSourceTransactionManager.java:267)
Committing JDBC transaction on Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@53ba89]
17:32:08.853 [http-bio-8080-exec-6] DEBUG org.mybatis.spring.SqlSessionUtils - Transaction synchronization committing SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@45ce57]
17:32:08.853 [http-bio-8080-exec-6] DEBUG org.mybatis.spring.SqlSessionUtils - Transaction synchronization closing SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@45ce57]
[DEBUG] 2018-05-21 17:32:08,854 method:org.springframework.jdbc.datasource.DataSourceTransactionManager.doCleanupAfterCompletion(DataSourceTransactionManager.java:325)
Releasing JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@53ba89] after transaction
[DEBUG] 2018-05-21 17:32:08,861 method:org.springframework.jdbc.datasource.DataSourceUtils.doReleaseConnection(DataSourceUtils.java:327)
Returning JDBC Connection to DataSource
---------scoreService updateScore end---------
[DEBUG] 2018-05-21 17:32:08,868 method:org.springframework.web.servlet.handler.AbstractHandlerExceptionResolver.resolveException(AbstractHandlerExceptionResolver.java:132)
Resolving exception from handler [public void com.paic.ssm.login.controller.LoginController.insert()]: java.lang.ArithmeticException: / by zero
[DEBUG] 2018-05-21 17:32:08,869 method:org.springframework.web.servlet.handler.AbstractHandlerExceptionResolver.resolveException(AbstractHandlerExceptionResolver.java:132)
Resolving exception from handler [public void com.paic.ssm.login.controller.LoginController.insert()]: java.lang.ArithmeticException: / by zero
[DEBUG] 2018-05-21 17:32:08,869 method:org.springframework.web.servlet.handler.AbstractHandlerExceptionResolver.resolveException(AbstractHandlerExceptionResolver.java:132)
Resolving exception from handler [public void com.paic.ssm.login.controller.LoginController.insert()]: java.lang.ArithmeticException: / by zero
[DEBUG] 2018-05-21 17:32:08,869 method:org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:974)
Could not complete request
java.lang.ArithmeticException: / by zero
at com.paic.ssm.user.service.impl.UserServiceImpl.update(UserServiceImpl.java:49)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)可以看到，在userService#update方法里面执行时，直到scoreService执行完毕，事务就紧接着提交，最后时刻，方法再抛出异常，已经为时已晚，查验DB，数据已修改，说明调用方userservice的异常不会影响被调用方scoreservice的事务
可以继续验证，打开scoreService的updateScore方法的异常测试代码，会发现scoreService已正常回滚，而userService无法回滚，很符合常识
---------scoreService updateScore start---------
[DEBUG] 2018-05-21 17:38:15,272 method:org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:243)
Returning cached instance of singleton bean 'transactionManager'
[DEBUG] 2018-05-21 17:38:15,276 method:org.springframework.transaction.support.AbstractPlatformTransactionManager.getTransaction(AbstractPlatformTransactionManager.java:366)
Creating new transaction with name [com.paic.ssm.user.service.impl.ScoreServiceImpl.updateScore]: PROPAGATION_REQUIRED,ISOLATION_DEFAULT; ''
[DEBUG] 2018-05-21 17:38:15,278 method:org.springframework.jdbc.datasource.DataSourceTransactionManager.doBegin(DataSourceTransactionManager.java:204)
Acquired Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@a6168] for JDBC transaction
Initiating transaction rollback
[DEBUG] 2018-05-21 17:38:15,289 method:org.springframework.jdbc.datasource.DataSourceTransactionManager.doRollback(DataSourceTransactionManager.java:282)
Rolling back JDBC transaction on Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@a6168]
17:38:15.319 [http-bio-8080-exec-3] DEBUG org.mybatis.spring.SqlSessionUtils - Transaction synchronization rolling back SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@bf617d]
4：UserServiceImpl#update不开启事务，ScoreService#updateScore不开启事务，不输出日志了
此时，两者均不会被事务作用，异常不会回滚，不赘述。
由于事务传播方式较多，但是系统大部分都是使用默认的事务传播方式，故其他的模式就不再测试了，经过测试发现，结果符合spring的传播方式的定义。
总结一下，如果要使用事务，一般是在service方法上进行标注，若初始调用某service，则事务会开启，即便后续调用其他service方法，事务仍会继续传播，所有service共用一个事务，任一方法抛出异常，如果被初始调用的service捕获，则方法回滚。若异常被底层预先捕获，则无法回滚了。
特别注意的是，如果初始调用无事务，则后续的方法调用不会影响它，即事务只会往后传播。。。
虽然spring事务传播的定义已经表述很清楚了，但是通过小实验，又加深了印象。
下期讨论下service里面开启新线程，事务的传播。。。