前言
最近项目有涉及到Spring事务,所以工作之余,想认真了解学习下Spring事务,查阅了若干资料,做了一个demo(PS:参考了大牛的)。
现分享总结如下:
1、Spring 事务的简介
理解事务之前,
先讲一个你日常生活中最常干的事:取钱。
比如你去ATM机取1000块钱,大体有两个步骤:首先输入密码金额,银行卡扣掉1000元钱;然后ATM出1000元钱。这两个步骤必须是要么都执行要么都不执行。如果银行卡扣除了1000块但是ATM出钱失败的话,你将会损失1000元;如果银行卡扣钱失败但是ATM却出了1000块,那么银行将损失1000元。所以,如果一个步骤成功另一个步骤失败对双方都不是好事,如果不管哪一个步骤失败了以后,整个取钱过程都能回滚,也就是完全取消所有操作的话,这对双方都是极好的。
事务就是用来解决类似问题的。事务是一系列的动作,它们综合在一起才是一个完整的工作单元,这些动作必须全部完成,如果有一个失败的话,那么事务就会回滚到最开始的状态,仿佛什么都没发生过一样。
在企业级应用程序开发中,事务管理必不可少的技术,用来确保数据的完整性和一致性。
事务有四个特性:ACID
- 原子性(Atomicity):事务是一个原子操作,由一系列动作组成。事务的原子性确保动作要么全部完成,要么完全不起作用。
- 一致性(Consistency):一旦事务完成(不管成功还是失败),系统必须确保它所建模的业务处于一致的状态,而不会是部分完成部分失败。在现实中的数据不应该被破坏。
- 隔离性(Isolation):可能有许多事务会同时处理相同的数据,因此每个事务都应该与其他事务隔离开来,防止数据损坏。
- 持久性(Durability):一旦事务完成,无论发生什么系统错误,它的结果都不应该受到影响,这样就能从任何系统崩溃中恢复过来。通常情况下,事务的结果被写到持久化存储器中。
具体可以参考:http://www.mamicode.com/info-detail-1248286.html
2、事务的传播行为
事务的第一个方面是传播行为(propagation behavior)。当事务方法被另一个事务方法调用时,必须指定事务应该如何传播。例如:方法可能继续在现有事务中运行,也可能开启一个新事务,并在自己的事务中运行。Spring定义了七种传播行为:
1、PROPAGATION_REQUIRED:如果当前没有事务,就创建一个新事务,如果当前存在事务,就加入该事务,该设置是最常用的设置。
2、PROPAGATION_SUPPORTS:支持当前事务,如果当前存在事务,就加入该事务,如果当前不存在事务,就以非事务执行。‘
3、PROPAGATION_MANDATORY:支持当前事务,如果当前存在事务,就加入该事务,如果当前不存在事务,就抛出异常。
4、PROPAGATION_REQUIRES_NEW:创建新事务,无论当前存不存在事务,都创建新事务。
5、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。
6、PROPAGATION_NEVER:以非事务方式执行,如果当前存在事务,则抛出异常。
7、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。
下面我们来看下代码:
3、demo分析
事先插入一条记录
@Override
public void before() {
jdbcTemplate.update("INSERT INTO USER (name,password) VALUES (?,?)","xiang","11111112");
}
3.1、PROPAGATION_REQUIRED:如果当前没有事务,就创建一个新事务,如果当前存在事务,就加入该事务,该设置是最常用的设置。
@Override
public void txRollbackInnerTxRollbackPropagationRequires() {
transactionTemplate.execute(new TransactionCallbackWithoutResult() {
@Override
protected void doInTransactionWithoutResult(TransactionStatus transactionStatus) {
jdbcTemplate.update("INSERT INTO USER (name,password) VALUES (?,?)","Huang","1111231");
transactionTemplate.execute(new TransactionCallbackWithoutResult() {
@Override
protected void doInTransactionWithoutResult(TransactionStatus transactionStatus) {
jdbcTemplate.update("insert into user name, password) values (?, ?)",
"Huang", "1111112");
//内部事务设置了 setRollbackOnly
transactionStatus.setRollbackOnly();
}
});
}
});
}
测试结果:
/**
* PROPAGATION_REQUIRES:内部事务设置了 {@link org.springframework.transaction.TransactionStatus#setRollbackOnly()} 来触发回滚,
* 外部事务接受到了一个 {@link UnexpectedRollbackException} 也被回滚
*/
@Test
public void testTxRollbackInnerTxRollbackPropagationRequires() throws Exception {
try {
springTxService.txRollbackInnerTxRollbackPropagationRequires();
} catch (UnexpectedRollbackException e) {
}finally {
Assert.assertEquals(1,springTxService.mysqlConnection());
}
}
3.2、PROPAGATION_SUPPORTS:支持当前事务,如果当前存在事务,就加入该事务,如果当前不存在事务,就以非事务执行。
@Override
public void txRollbackInnerTxRollbackPropagationSupports() {
supportsTransactionTemplate.execute(new TransactionCallbackWithoutResult() {
@Override
protected void doInTransactionWithoutResult(TransactionStatus transactionStatus) {
jdbcTemplate.update("insert into user (name, password) values (?, ?)", "Huang",
"1111112");
throw new CustomRuntimeException();
}
});
}
@Override
public void txRollbackInnerTxRollbackPropagationSupports2() {
transactionTemplate.execute(new TransactionCallbackWithoutResult() {
@Override
protected void doInTransactionWithoutResult(TransactionStatus transactionStatus) {
jdbcTemplate.update("insert into user (name, password) values (?, ?)", "Huang",
"1111112");
supportsTransactionTemplate.execute(new TransactionCallbackWithoutResult() {
@Override
protected void doInTransactionWithoutResult(TransactionStatus status) {
jdbcTemplate.update("insert into user (name, password) values (?, ?)",
"Huang", "1111112");
status.setRollbackOnly();
}
});
}
});
}
测试用例:
/**
* PROPAGATION_SUPPORTS:如果当前事务上下文中没有事务,
* 那么就按照没有事务的方式执行代码
*/
@Test
public void testTxRollbackInnerTxRollbackPropagationSupports() throws Exception {
try {
springTxService.txRollbackInnerTxRollbackPropagationSupports();
} catch (CustomRuntimeException e) {
e.printStackTrace();
}finally {
Assert.assertEquals(2, springTxService.mysqlConnection());
}
}
/**
* PROPAGATION_SUPPORTS:如果当前事务上下文中存在事务,
* 那么合并到当前上下文的事务中去,
* 表现地和 {@link org.springframework.transaction.TransactionDefinition#PROPAGATION_REQUIRED} 一样
*/
@Test(expected = UnexpectedRollbackException.class)
public void testTxRollbackInnerTxRollbackPropagationSupports2() throws Exception {
springTxService.txRollbackInnerTxRollbackPropagationSupports2();
}
3.3、PROPAGATION_MANDATORY:支持当前事务,如果当前存在事务,就加入该事务,如果当前不存在事务,就抛出异常。
@Override
public void txRollbackInnerTxRollbackPropagationMandatory() {
mandatoryTransactionTemplate.execute(new TransactionCallbackWithoutResult() {
@Override
protected void doInTransactionWithoutResult(TransactionStatus transactionStatus) {
jdbcTemplate.update("insert into user (name, password) values (?, ?)", "Huang",
"1111112");
}
});
}
@Override
public void txRollbackInnerTxRollbackPropagationMandatory2() {
nestedTransactionTemplate.execute(new TransactionCallbackWithoutResult() {
@Override
protected void doInTransactionWithoutResult(TransactionStatus transactionStatus) {
jdbcTemplate.update("insert into user (name, password) values (?, ?)", "Huang",
"1111112");
mandatoryTransactionTemplate.execute(new TransactionCallbackWithoutResult() {
@Override
protected void doInTransactionWithoutResult(TransactionStatus transactionStatus) {
jdbcTemplate.update("insert into user (name, password) values (?, ?)",
"Huang", "1111112");
//内部事务回滚了,外部事务也跟着回滚
transactionStatus.setRollbackOnly();
}
});
}
});
}
测试用例:
/**
* PROPAGATION_MANDATORY:强制性的事务,当前的事务上下文中不存在事务的话,会抛出 {@link IllegalTransactionStateException}
*/
@Test(expected = IllegalTransactionStateException.class)
public void testTxRollbackInnerTxRollbackPropagationMandatory() throws Exception {
springTxService.txRollbackInnerTxRollbackPropagationMandatory();
}
/**
* PROPAGATION_MANDATORY:强制性的事务,内部的事务发生回滚,
* 那么外部的事务也会发生回滚,表现地和 {@link org.springframework.transaction.TransactionDefinition#PROPAGATION_REQUIRED}
* 一样,也会抛出 {@link UnexpectedRollbackException}
*/
@Test(expected = UnexpectedRollbackException.class)
public void testTxRollbackInnerTxRollbackPropagationMandatory2() throws Exception {
springTxService.txRollbackInnerTxRollbackPropagationMandatory2();
}
3.4、PROPAGATION_REQUIRES_NEW:创建新事务,无论当前存不存在事务,都创建新事务。
@Override
public void txRollbackInnerTxRollbackPropagationRequiresNew() {
transactionTemplate.execute(new TransactionCallbackWithoutResult() {
@Override
protected void doInTransactionWithoutResult(TransactionStatus transactionStatus) {
requiresNewTransactionTemplate.execute(new TransactionCallbackWithoutResult() {
@Override
protected void doInTransactionWithoutResult(TransactionStatus transactionStatus) {
jdbcTemplate.update("insert into user (name, password) values (?, ?)",
"Huang", "1111112");
}
});
//外部事务发生回滚,内部事务应该不受影响还是能够提交
throw new RuntimeException();
}
});
}
@Override
public void txRollbackInnerTxRollbackPropagationRequiresNew2() {
transactionTemplate.execute(new TransactionCallbackWithoutResult() {
@Override
protected void doInTransactionWithoutResult(TransactionStatus transactionStatus) {
jdbcTemplate.update("insert into user (name, password) values (?, ?)", "Huang",
"1111112");
requiresNewTransactionTemplate.execute(new TransactionCallbackWithoutResult() {
@Override
protected void doInTransactionWithoutResult(TransactionStatus transactionStatus) {
jdbcTemplate.update("insert into user (name, password) values (?, ?)",
"Huang", "1111112");
// 内部事务发生回滚,但是外部事务不应该发生回滚
transactionStatus.setRollbackOnly();
}
});
}
});
}
@Override
public void txRollbackInnerTxRollbackPropagationRequiresNew3() {
transactionTemplate.execute(new TransactionCallbackWithoutResult() {
@Override
protected void doInTransactionWithoutResult(TransactionStatus transactionStatus) {
jdbcTemplate.update("insert into user (name, password) values (?, ?)", "Huang",
"1111112");
requiresNewTransactionTemplate.execute(new TransactionCallbackWithoutResult() {
@Override
protected void doInTransactionWithoutResult(TransactionStatus transactionStatus) {
jdbcTemplate.update("insert into user (name, password) values (?, ?)",
"Huang", "1111112");
// 内部事务抛出 RuntimeException,外部事务接收到异常,依旧会发生回滚
throw new RuntimeException();
}
});
}
});
}
测试用例:
/**
* PROPAGATION_REQUIRES_NEW:外部事务发生回滚,内部事务继续提交,不受影响
*/
@Test
public void testTxRollbackInnerTxRollbackPropagationRequiresNew() throws Exception {
try {
springTxService.txRollbackInnerTxRollbackPropagationRequiresNew();
} catch (Exception e) {
e.printStackTrace();
}finally {
Assert.assertEquals(2,springTxService.mysqlConnection());
}
}
/**
* PROPAGATION_REQUIRES_NEW:内部事务通过设置 {@link org.springframework.transaction.TransactionStatus#setRollbackOnly()} 来触发回滚,
* 外部事务依旧可以不受影响,正常提交
*/
@Test
public void testTxRollbackInnerTxRollbackPropagationRequiresNew2() throws Exception {
springTxService.txRollbackInnerTxRollbackPropagationRequiresNew2();
Assert.assertEquals(2,springTxService.mysqlConnection());
}
/**
* PROPAGATION_REQUIRES_NEW:内部事务抛出了 {@link RuntimeException} 异常发生了回滚,外部事务接收到这个异常也会发生回滚
*/
@Test
public void testTxRollbackInnerTxRollbackPropagationRequiresNew3() throws Exception {
try {
springTxService.txRollbackInnerTxRollbackPropagationRequiresNew3();
} catch (RuntimeException e) {
e.printStackTrace();
}finally {
Assert.assertEquals(1,springTxService.mysqlConnection());
}
}
3.5、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。
@Override
public void txRollbackInnerTxRollbackPropagationNotSupport() {
transactionTemplate.execute(new TransactionCallbackWithoutResult() {
@Override
protected void doInTransactionWithoutResult(TransactionStatus transactionStatus) {
jdbcTemplate.update("insert into user (name, password) values (?, ?)", "Huang",
"1111112");
notSupportedTransactionTemplate.execute(new TransactionCallbackWithoutResult() {
@Override
protected void doInTransactionWithoutResult(TransactionStatus status) {
jdbcTemplate.update("insert into user (name, password) values (?, ?)",
"Huang", "1111112");
}
});
// 外部事务回滚,不会把内部的也连着回滚
transactionStatus.setRollbackOnly();
}
});
}
@Override
public void txRollbackInnerTxRollbackPropagationNotSupport2() {
transactionTemplate.execute(new TransactionCallbackWithoutResult() {
@Override
protected void doInTransactionWithoutResult(TransactionStatus transactionStatus) {
try {
notSupportedTransactionTemplate.execute(new TransactionCallbackWithoutResult() {
@Override
protected void doInTransactionWithoutResult(TransactionStatus transactionStatus) {
jdbcTemplate.update("insert into user (name, password) values (?, ?)",
"Huang", "1111112");
throw new CustomRuntimeException();
}
});
} catch (CustomRuntimeException e) {
}
}
});
}
测试用例:
/**
* PROPAGATION_NOT_SUPPORTED:不支持事务,
* 外围的事务回滚不会导致它包含的内容回滚
*/
@Test
public void testTxRollbackInnerTxRollbackPropagationNotSupport() throws Exception {
springTxService.txRollbackInnerTxRollbackPropagationNotSupport();
Assert.assertEquals(2,springTxService.mysqlConnection());
}
/**
* PROPAGATION_NOT_SUPPORTED:不支持事务,内部发生异常,外部捕获,都不会发生回滚
*/
@Test
public void testTxRollbackInnerTxRollbackPropagationNotSupport2() throws Exception {
springTxService.txRollbackInnerTxRollbackPropagationNotSupport2();
Assert.assertEquals(3,springTxService.mysqlConnection());
}
3.6、PROPAGATION_NEVER:以非事务方式执行,如果当前存在事务,则抛出异常。
1 @Override
2 public void txRollbackInnerTxRollbackPropagationNever() {
3 neverTransactionTemplate.execute(new TransactionCallbackWithoutResult() {
4 @Override
5 protected void doInTransactionWithoutResult(TransactionStatus transactionStatus) {
6 jdbcTemplate.update("insert into user (name, password) values (?, ?)", "Huang",
7 "1111112");
8 }
9 });
10 }
11
12 @Override
13 public void txRollbackInnerTxRollbackPropagationNever2() {
14 transactionTemplate.execute(new TransactionCallbackWithoutResult() {
15 @Override
16 protected void doInTransactionWithoutResult(TransactionStatus transactionStatus) {
17 jdbcTemplate.update("insert into user (name, password) values (?, ?)", "Huang",
18 "1111112");
19 neverTransactionTemplate.execute(new TransactionCallbackWithoutResult() {
20 @Override
21 protected void doInTransactionWithoutResult(TransactionStatus transactionStatus) {
22 jdbcTemplate.update("insert into user (name, password) values (?, ?)",
23 "Huang", "1111112");
24 }
25 });
26 }
27 });
28 }
29
30 @Override
31 public void txRollbackInnerTxRollbackPropagationNever3() {
32 neverTransactionTemplate.execute(new TransactionCallbackWithoutResult() {
33 @Override
34 protected void doInTransactionWithoutResult(TransactionStatus transactionStatus) {
35 jdbcTemplate.update("insert into user (name, password) values (?, ?)", "Huang",
36 "1111112");
37 neverTransactionTemplate.execute(new TransactionCallbackWithoutResult() {
38 @Override
39 protected void doInTransactionWithoutResult(TransactionStatus status) {
40 jdbcTemplate.update("insert into user (name, password) values (?, ?)",
41 "Huang", "1111112");
42 }
43 });
44 }
45 });
46 }
View Code
测试代码:
/**
* PROPAGATION_NEVER:不允许当前事务上下文中存在事务,如果没有,就正常执行
*/
@Test
public void testTxRollbackInnerTxRollbackPropagationNever() throws Exception {
springTxService.txRollbackInnerTxRollbackPropagationNever();
Assert.assertEquals(2,springTxService.mysqlConnection());
}
/**
* PROPAGATION_NEVER:不允许当前事务上下文中存在事务,
* 如果有,则抛出 {@link IllegalTransactionStateException}
*/
@Test(expected = IllegalTransactionStateException.class)
public void testTxRollbackInnerTxRollbackPropagationNever2() throws Exception {
springTxService.txRollbackInnerTxRollbackPropagationNever2();
}
/**
* PROPAGATION_NEVER:不允许当前事务上下文中存在事务,
* 当两个 NEVER 的嵌套在一起的时候,应该也是能够执行成功的。
*/
@Test
public void testTxRollbackInnerTxRollbackPropagationNever3() throws Exception {
springTxService.txRollbackInnerTxRollbackPropagationNever3();
Assert.assertEquals(3,springTxService.mysqlConnection());
}
3.7、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。
@Override
public void txRollbackInnerTxRollbackPropagationNested() {
nestedTransactionTemplate.execute(new TransactionCallbackWithoutResult() {
@Override
protected void doInTransactionWithoutResult(TransactionStatus transactionStatus) {
jdbcTemplate.update("insert into user (name, password) values (?, ?)", "Huang",
"1111112");
nestedTransactionTemplate.execute(new TransactionCallbackWithoutResult() {
@Override
protected void doInTransactionWithoutResult(TransactionStatus transactionStatus) {
jdbcTemplate.update("insert into user (name, password) values (?, ?)", "Huang",
"1111112");
// 内部事务设置了 rollbackOnly,外部事务应该不受影响,可以继续提交
transactionStatus.setRollbackOnly();
}
});
}
});
}
@Override
public void txRollbackInnerTxRollbackPropagationNested2() {
nestedTransactionTemplate.execute(new TransactionCallbackWithoutResult() {
@Override
protected void doInTransactionWithoutResult(TransactionStatus transactionStatus) {
jdbcTemplate.update("insert into user (name, password) values (?, ?)", "Huang",
"1111112");
nestedTransactionTemplate.execute(new TransactionCallbackWithoutResult() {
@Override
protected void doInTransactionWithoutResult(TransactionStatus transactionStatus) {
jdbcTemplate.update("insert into user (name, password) values (?, ?)",
"Huang", "1111112");
}
});
// 外部事务设置了 rollbackOnly,内部事务应该也被回滚掉
transactionStatus.setRollbackOnly();
}
});
}
测试代码:
/**
* PROPAGATION_NESTED:内部事务通过设置 {@link org.springframework.transaction.TransactionStatus#setRollbackOnly()} 来触发回滚,
* 外部事务依旧可以不受影响,正常提交
*/
@Test
public void testTxRollbackInnerTxRollbackPropagationNested() throws Exception {
springTxService.txRollbackInnerTxRollbackPropagationNested();
Assert.assertEquals(2, springTxService.mysqlConnection());
}
/**
* PROPAGATION_NESTED:外部事务通过设置 {@link org.springframework.transaction.TransactionStatus#setRollbackOnly()} 来触发回滚,由于
* savepoint 在外部事务的开头,所以内部事务应该也会被一起回滚掉
*/
@Test
public void testTxRollbackInnerTxRollbackPropagationNested2() throws Exception {
springTxService.txRollbackInnerTxRollbackPropagationNested2();
Assert.assertEquals(1, springTxService.mysqlConnection());
}