今天小编给大家分享的是一文解析spring中事务的传播机制，相信很多人都不太了解，为了让大家更加了解，所以给大家总结了以下内容，一起往下看吧。一定会有所收获的哦。
Spring中的事务
Spring的事务其实就是数据库的事务操作，符合ACID标准，也具有标准的事务隔离级别。
Spring中的事务只是对JDBC事务进行一些封装与扩展，其底层最终还是会使用到JDBC的这套API。但是Spring事务有自己的特点，也就是事务传播机制。
所谓事务传播机制，也就是在事务在多个方法的调用中是如何传递的，是重新创建事务还是使用父方法的事务？父方法的回滚对子方法的事务是否有影响？这些都是可以通过事务传播机制来决定的。
准备工作
实体类
Area
package com.morris.spring.entity;import lombok.Data;import java.io.Serializable;@Datapublic class Area implements Serializable {private Integer id;private String areaName;private Integer areaCode;}
Good
package com.morris.spring.entity;import lombok.Data;import java.io.Serializable;import java.math.BigDecimal;@Datapublic class Good implements Serializable {private Integer id;private String goodName;private BigDecimal price;}
DAO层
AreaDao
package com.morris.spring.dao;import com.morris.spring.entity.Area;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.jdbc.core.JdbcTemplate;public class AreaDao {@Autowiredprivate JdbcTemplate jdbcTemplate;public boolean insert(Area area) {String sql = "insert into t_area(area_name, area_code) values(?,?)";return jdbcTemplate.update(sql, area.getAreaName(), area.getAreaCode()) > 0;}}
GoodDao
package com.morris.spring.dao;import com.morris.spring.entity.Good;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.jdbc.core.JdbcTemplate;public class GoodDao {@Autowiredprivate JdbcTemplate jdbcTemplate;public boolean insert(Good good) {String sql = "insert into t_good(good_name, price) values(?,?)";return jdbcTemplate.update(sql, good.getGoodName(), good.getPrice()) > 0;}}
Service层
AreaServiceImpl
package com.morris.spring.service;import com.morris.spring.dao.AreaDao;import com.morris.spring.entity.Area;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.transaction.annotation.Propagation;import org.springframework.transaction.annotation.Transactional;public class AreaServiceImpl implements AreaService {@Autowiredprivate AreaDao areaDao;@Transactional(propagation = Propagation.REQUIRED)@Overridepublic boolean addArea(int i) {int y = 1000000 / i;Area area = new Area();area.setAreaCode(y);area.setAreaName("shenzhen");return areaDao.insert(area);}}
GoodServiceImpl
package com.morris.spring.service;import com.morris.spring.dao.GoodDao;import com.morris.spring.entity.Good;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.transaction.annotation.Propagation;import org.springframework.transaction.annotation.Transactional;import java.math.BigDecimal;public class GoodServiceImpl implements GoodService {@Autowiredprivate GoodDao goodDao;@Transactional(propagation = Propagation.REQUIRED)@Overridepublic boolean addGood() {Good good = new Good();good.setGoodName("iphone");good.setPrice(BigDecimal.valueOf(99999));return goodDao.insert(good);}}TransactionService
package com.morris.spring.service;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Component;import org.springframework.transaction.annotation.Propagation;import org.springframework.transaction.annotation.Transactional;@Componentpublic class TransactionService {@Autowiredprivate GoodService goodService;@Autowiredprivate AreaService areaService;@Transactional(propagation = Propagation.REQUIRED)public void addGoodAndArea() {System.out.println("------addGoodAndArea-------");areaService.addArea(10);goodService.addGood();}}测试类
TransactionPropagationDemo
package com.morris.spring.demo.jdbc;import com.morris.spring.config.JdbcConfig;import com.morris.spring.dao.AreaDao;import com.morris.spring.dao.GoodDao;import com.morris.spring.service.AreaServiceImpl;import com.morris.spring.service.GoodServiceImpl;import com.morris.spring.service.TransactionService;import org.junit.jupiter.api.Test;import org.springframework.context.annotation.AnnotationConfigApplicationContext;public class TransactionPropagationDemo {@Testpublic void test() {AnnotationConfigApplicationContext applicationContext = new AnnotationConfigApplicationContext();applicationContext.register(GoodDao.class);applicationContext.register(AreaDao.class);applicationContext.register(GoodServiceImpl.class);applicationContext.register(AreaServiceImpl.class);applicationContext.register(JdbcConfig.class);applicationContext.register(TransactionService.class);applicationContext.refresh();TransactionService transactionService = applicationContext.getBean(TransactionService.class);transactionService.addGoodAndArea();}}传播机制
具体选项可以参考枚举类org.springframework.transaction.annotation.Propagation。
| 选项 | 说明 |
| REQUIRED | 默认选项。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。 |
| SUPPORTS | 支持当前事务，如果当前没有事务，就以非事务方式执行。 |
| MANDATORY | 使用当前的事务，如果当前没有事务，就抛出异常。 |
| REQUIRES_NEW | 新建事务，如果当前存在事务，把当前事务挂起。 |
| 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。 |
| NEVER | 以非事务方式执行，如果当前存在事务，则抛出异常。 |
| 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REQUIRED类似的操作。 |
REQUIRED
默认选项。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。
配置如下：
TransactionService：REQUIRED
AreaServiceImpl：REQUIRED
GoodServiceImpl：REQUIRED
运行上面的Demo，运行结果如下：
// 创建第一个事务DEBUG DataSourceTransactionManager:381 - Creating new transaction with name [com.morris.spring.service.TransactionService.addGoodAndArea]: PROPAGATION_REQUIRED,ISOLATION_DEFAULT// 创建第一个连接DEBUG DriverManagerDataSource:144 - Creating new JDBC DriverManager Connection to [jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&allowMultiQueries=true&characterEncoding=UTF-8&useFastDateParsing=false&zeroDateTimeBehavior=convertToNull]DEBUG DataSourceTransactionManager:265 - Acquired Connection [com.mysql.cj.jdbc.ConnectionImpl@8ef162] for JDBC transactionDEBUG DataSourceTransactionManager:283 - Switching JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@8ef162] to manual commit------addGoodAndArea------- // 在第一个事务中执行DEBUG DataSourceTransactionManager:487 - Participating in existing transactionDEBUG JdbcTemplate:860 - Executing prepared SQL updateDEBUG JdbcTemplate:609 - Executing prepared SQL statement [insert into t_good(good_name, price) values(?,?)]// 在第一个事务中执行DEBUG DataSourceTransactionManager:487 - Participating in existing transactionDEBUG JdbcTemplate:860 - Executing prepared SQL updateDEBUG JdbcTemplate:609 - Executing prepared SQL statement [insert into t_area(area_name, area_code) values(?,?)]// 提交第一个事务DEBUG DataSourceTransactionManager:763 - Initiating transaction commitDEBUG DataSourceTransactionManager:329 - Committing JDBC transaction on Connection [com.mysql.cj.jdbc.ConnectionImpl@8ef162]DEBUG DataSourceTransactionManager:390 - Releasing JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@8ef162] after transaction总结：
当外层没有事务的时候，TransactionService.addGoodAndArea()方法执行发现没有事务可用，自己新建事务。
goodService.addGood()和areaService.addArea()执行时发现已有事务，就使用当前事务执行。
REQUIRES_NEW
新建事务，如果当前存在事务，把当前事务挂起。
配置如下：
TransactionService：REQUIRED
GoodServiceImpl：REQUIRES
AreaServiceImpl：REQUIRES_NEW
运行结果如下：
// 创建第一个事务DEBUG DataSourceTransactionManager:381 - Creating new transaction with name [com.morris.spring.service.TransactionService.addGoodAndArea]: PROPAGATION_REQUIRED,ISOLATION_DEFAULT// 创建第一个连接DEBUG DriverManagerDataSource:144 - Creating new JDBC DriverManager Connection to [jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&allowMultiQueries=true&characterEncoding=UTF-8&useFastDateParsing=false&zeroDateTimeBehavior=convertToNull]DEBUG DataSourceTransactionManager:265 - Acquired Connection [com.mysql.cj.jdbc.ConnectionImpl@f9aa66] for JDBC transactionDEBUG DataSourceTransactionManager:283 - Switching JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@f9aa66] to manual commit------addGoodAndArea------- // 挂起第一个事务并创建第二个事务DEBUG DataSourceTransactionManager:446 - Suspending current transaction, creating new transaction with name [com.morris.spring.service.AreaServiceImpl.addArea]// 创建第二个连接DEBUG DriverManagerDataSource:144 - Creating new JDBC DriverManager Connection to [jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&allowMultiQueries=true&characterEncoding=UTF-8&useFastDateParsing=false&zeroDateTimeBehavior=convertToNull]DEBUG DataSourceTransactionManager:265 - Acquired Connection [com.mysql.cj.jdbc.ConnectionImpl@116fc68] for JDBC transactionDEBUG DataSourceTransactionManager:283 - Switching JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@116fc68] to manual commitDEBUG JdbcTemplate:860 - Executing prepared SQL updateDEBUG JdbcTemplate:609 - Executing prepared SQL statement [insert into t_area(area_name, area_code) values(?,?)]// 提交第二个事务DEBUG DataSourceTransactionManager:763 - Initiating transaction commitDEBUG DataSourceTransactionManager:329 - Committing JDBC transaction on Connection [com.mysql.cj.jdbc.ConnectionImpl@116fc68]DEBUG DataSourceTransactionManager:390 - Releasing JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@116fc68] after transaction// 恢复第一个事务DEBUG DataSourceTransactionManager:1043 - Resuming suspended transaction after completion of inner transaction// 在第一个事务中执行DEBUG DataSourceTransactionManager:487 - Participating in existing transactionDEBUG JdbcTemplate:860 - Executing prepared SQL updateDEBUG JdbcTemplate:609 - Executing prepared SQL statement [insert into t_good(good_name, price) values(?,?)]DEBUG DataSourceTransactionManager:763 - Initiating transaction commitDEBUG DataSourceTransactionManager:329 - Committing JDBC transaction on Connection [com.mysql.cj.jdbc.ConnectionImpl@f9aa66]DEBUG DataSourceTransactionManager:390 - Releasing JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@f9aa66] after transaction总结：areaServiceImpl.addArea()执行时发现已有事务，就把当前事务挂起，执行完后再恢复。
SUPPORTS
支持当前事务，如果当前没有事务，就以非事务方式执行。
配置如下：
TransactionService：SUPPORTS
AreaServiceImpl：REQUIRED
GoodServiceImpl：SUPPORTS
运行结果如下：
// TransactionService.addGoodAndArea以非事务方式运行------addGoodAndArea-------// 开启第一个事务DEBUG DataSourceTransactionManager:381 - Creating new transaction with name [com.morris.spring.service.AreaServiceImpl.addArea]: PROPAGATION_REQUIRED,ISOLATION_DEFAULT// 创建第一个连接DEBUG DriverManagerDataSource:144 - Creating new JDBC DriverManager Connection to [jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&allowMultiQueries=true&characterEncoding=UTF-8&useFastDateParsing=false&zeroDateTimeBehavior=convertToNull]DEBUG DataSourceTransactionManager:265 - Acquired Connection [com.mysql.cj.jdbc.ConnectionImpl@1691f3d] for JDBC transactionDEBUG DataSourceTransactionManager:283 - Switching JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@1691f3d] to manual commitDEBUG JdbcTemplate:860 - Executing prepared SQL updateDEBUG JdbcTemplate:609 - Executing prepared SQL statement [insert into t_area(area_name, area_code) values(?,?)]// 提交第一个事务DEBUG DataSourceTransactionManager:763 - Initiating transaction commitDEBUG DataSourceTransactionManager:329 - Committing JDBC transaction on Connection [com.mysql.cj.jdbc.ConnectionImpl@1691f3d]DEBUG DataSourceTransactionManager:390 - Releasing JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@1691f3d] after transactionDEBUG DataSourceTransactionManager:1043 - Resuming suspended transaction after completion of inner transaction// AreaServiceImpl.addArea以非事务方式运行DEBUG JdbcTemplate:860 - Executing prepared SQL updateDEBUG JdbcTemplate:609 - Executing prepared SQL statement [insert into t_good(good_name, price) values(?,?)]总结：当前没有事务，TransactionService.addGoodAndArea()和AreaServiceImpl.addArea()以非事务方式运行。
修改配置如下：
TransactionService：REQUIRED
AreaServiceImpl：SUPPORTS
GoodServiceImpl：SUPPORTS
运行结果如下：
// 开启第一个事务DEBUG DataSourceTransactionManager:381 - Creating new transaction with name [com.morris.spring.service.TransactionService.addGoodAndArea]: PROPAGATION_REQUIRED,ISOLATION_DEFAULT// 创建第一个连接DEBUG DriverManagerDataSource:144 - Creating new JDBC DriverManager Connection to [jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&allowMultiQueries=true&characterEncoding=UTF-8&useFastDateParsing=false&zeroDateTimeBehavior=convertToNull]DEBUG DataSourceTransactionManager:265 - Acquired Connection [com.mysql.cj.jdbc.ConnectionImpl@11158fb] for JDBC transactionDEBUG DataSourceTransactionManager:283 - Switching JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@11158fb] to manual commit------addGoodAndArea------- // 在第一个事务中执行DEBUG DataSourceTransactionManager:487 - Participating in existing transactionDEBUG JdbcTemplate:860 - Executing prepared SQL updateDEBUG JdbcTemplate:609 - Executing prepared SQL statement [insert into t_area(area_name, area_code) values(?,?)]// 在第一个事务中执行DEBUG DataSourceTransactionManager:487 - Participating in existing transactionDEBUG JdbcTemplate:860 - Executing prepared SQL updateDEBUG JdbcTemplate:609 - Executing prepared SQL statement [insert into t_good(good_name, price) values(?,?)]// 提交第一个事务DEBUG DataSourceTransactionManager:763 - Initiating transaction commitDEBUG DataSourceTransactionManager:329 - Committing JDBC transaction on Connection [com.mysql.cj.jdbc.ConnectionImpl@11158fb]DEBUG DataSourceTransactionManager:390 - Releasing JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@11158fb] after transaction总结：当前有事务，GoodServiceImpl.addGood()和AreaServiceImpl.addArea()以事务方式运行。
MANDATORY
使用当前的事务，如果当前没有事务，就抛出异常。
配置如下：
TransactionService：REQUIRED
AreaServiceImpl：REQUIRED
GoodServiceImpl：MANDATORY
运行结果如下：
// 创建第一个事务EBUG DataSourceTransactionManager:381 - Creating new transaction with name [com.morris.spring.service.TransactionService.addGoodAndArea]: PROPAGATION_REQUIRED,ISOLATION_DEFAULT// 创建第一个连接DEBUG DriverManagerDataSource:144 - Creating new JDBC DriverManager Connection to [jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&allowMultiQueries=true&characterEncoding=UTF-8&useFastDateParsing=false&zeroDateTimeBehavior=convertToNull]DEBUG DataSourceTransactionManager:265 - Acquired Connection [com.mysql.cj.jdbc.ConnectionImpl@11c4a3f] for JDBC transactionDEBUG DataSourceTransactionManager:283 - Switching JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@11c4a3f] to manual commit------addGoodAndArea------- // 在第一个事务中执行DEBUG DataSourceTransactionManager:487 - Participating in existing transactionDEBUG JdbcTemplate:860 - Executing prepared SQL updateDEBUG JdbcTemplate:609 - Executing prepared SQL statement [insert into t_area(area_name, area_code) values(?,?)]// 在第一个事务中执行DEBUG DataSourceTransactionManager:487 - Participating in existing transactionDEBUG JdbcTemplate:860 - Executing prepared SQL updateDEBUG JdbcTemplate:609 - Executing prepared SQL statement [insert into t_good(good_name, price) values(?,?)]// 提交第一个事务DEBUG DataSourceTransactionManager:763 - Initiating transaction commitDEBUG DataSourceTransactionManager:329 - Committing JDBC transaction on Connection [com.mysql.cj.jdbc.ConnectionImpl@11c4a3f]DEBUG DataSourceTransactionManager:390 - Releasing JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@11c4a3f] after transaction总结：当前有事务，GoodServiceImpl.addGood()以事务方式运行。
修改配置如下：
TransactionService：SUPPORTS
AreaServiceImpl：MANDATORY
GoodServiceImpl：SUPPORTS
运行结果如下：
------addGoodAndArea-------DEBUG DataSourceTransactionManager:888 - Should roll back transaction but cannot - no transaction availableorg.springframework.transaction.IllegalTransactionStateException: No existing transaction found for transaction marked with propagation 'mandatory'at org.springframework.transaction.support.AbstractPlatformTransactionManager.getTransaction(AbstractPlatformTransactionManager.java:372)at org.springframework.transaction.interceptor.TransactionAspectSupport.createTransactionIfNecessary(TransactionAspectSupport.java:595)at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:374)at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:118)at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:205)at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:219)at com.sun.proxy.$Proxy23.addArea(Unknown Source)at com.morris.spring.service.TransactionService.addGoodAndArea(TransactionService.java:20)总结：当前没有有事务，AreaServiceImpl.addArea()会抛出异常。
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。
配置如下：
TransactionService：REQUIRED
AreaServiceImpl：NOT_SUPPORTED
GoodServiceImpl：NOT_SUPPORTED
运行结果如下：
// 开启第一个事务DEBUG DataSourceTransactionManager:381 - Creating new transaction with name [com.morris.spring.service.TransactionService.addGoodAndArea]: PROPAGATION_REQUIRED,ISOLATION_DEFAULTDEBUG DriverManagerDataSource:144 - Creating new JDBC DriverManager Connection to [jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&allowMultiQueries=true&characterEncoding=UTF-8&useFastDateParsing=false&zeroDateTimeBehavior=convertToNull]DEBUG DataSourceTransactionManager:265 - Acquired Connection [com.mysql.cj.jdbc.ConnectionImpl@8ef162] for JDBC transactionDEBUG DataSourceTransactionManager:283 - Switching JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@8ef162] to manual commit------addGoodAndArea-------// 挂起第一个事务DEBUG DataSourceTransactionManager:436 - Suspending current transaction// 以非事务方式运行DEBUG JdbcTemplate:860 - Executing prepared SQL updateDEBUG JdbcTemplate:609 - Executing prepared SQL statement [insert into t_area(area_name, area_code) values(?,?)]DEBUG DataSourceUtils:115 - Fetching JDBC Connection from DataSourceDEBUG DriverManagerDataSource:144 - Creating new JDBC DriverManager Connection to [jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&allowMultiQueries=true&characterEncoding=UTF-8&useFastDateParsing=false&zeroDateTimeBehavior=convertToNull]// 恢复第一个事务DEBUG DataSourceTransactionManager:1043 - Resuming suspended transaction after completion of inner transaction// 挂起第一个事务DEBUG DataSourceTransactionManager:436 - Suspending current transaction// 以非事务方式运行DEBUG JdbcTemplate:860 - Executing prepared SQL updateDEBUG JdbcTemplate:609 - Executing prepared SQL statement [insert into t_good(good_name, price) values(?,?)]DEBUG DataSourceUtils:115 - Fetching JDBC Connection from DataSourceDEBUG DriverManagerDataSource:144 - Creating new JDBC DriverManager Connection to [jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&allowMultiQueries=true&characterEncoding=UTF-8&useFastDateParsing=false&zeroDateTimeBehavior=convertToNull]// 恢复第一个事务DEBUG DataSourceTransactionManager:1043 - Resuming suspended transaction after completion of inner transaction// 提交第一个事务DEBUG DataSourceTransactionManager:763 - Initiating transaction commitDEBUG DataSourceTransactionManager:329 - Committing JDBC transaction on Connection [com.mysql.cj.jdbc.ConnectionImpl@8ef162]DEBUG DataSourceTransactionManager:390 - Releasing JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@8ef162] after transaction总结：执行GoodServiceImpl.addGood()和AreaServiceImpl.addArea()时当前存在事务，就把当前事务挂起。
NEVER
以非事务方式执行，如果当前存在事务，则抛出异常。
配置如下：
TransactionService：NEVER
AreaServiceImpl：NEVER
GoodServiceImpl：NEVER
运行结果如下：
// 没有事务都以非事务方式运行------addGoodAndArea-------DEBUG JdbcTemplate:860 - Executing prepared SQL updateDEBUG JdbcTemplate:609 - Executing prepared SQL statement [insert into t_area(area_name, area_code) values(?,?)]DEBUG DataSourceUtils:115 - Fetching JDBC Connection from DataSourceDEBUG DriverManagerDataSource:144 - Creating new JDBC DriverManager Connection to [jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&allowMultiQueries=true&characterEncoding=UTF-8&useFastDateParsing=false&zeroDateTimeBehavior=convertToNull]DEBUG JdbcTemplate:860 - Executing prepared SQL updateDEBUG JdbcTemplate:609 - Executing prepared SQL statement [insert into t_good(good_name, price) values(?,?)]总结：当前没有事务都以非事务方式执行。
修改配置如下：
TransactionService：REQUIRED
AreaServiceImpl：NEVER
GoodServiceImpl：NEVER
运行结果如下：
// 开启第一个事务DEBUG DataSourceTransactionManager:381 - Creating new transaction with name [com.morris.spring.service.TransactionService.addGoodAndArea]: PROPAGATION_REQUIRED,ISOLATION_DEFAULTDEBUG DriverManagerDataSource:144 - Creating new JDBC DriverManager Connection to [jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&allowMultiQueries=true&characterEncoding=UTF-8&useFastDateParsing=false&zeroDateTimeBehavior=convertToNull]DEBUG DataSourceTransactionManager:265 - Acquired Connection [com.mysql.cj.jdbc.ConnectionImpl@8ef162] for JDBC transactionDEBUG DataSourceTransactionManager:283 - Switching JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@8ef162] to manual commit------addGoodAndArea-------DEBUG DataSourceTransactionManager:864 - Initiating transaction rollbackDEBUG DataSourceTransactionManager:345 - Rolling back JDBC transaction on Connection [com.mysql.cj.jdbc.ConnectionImpl@8ef162]DEBUG DataSourceTransactionManager:390 - Releasing JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@8ef162] after transactionorg.springframework.transaction.IllegalTransactionStateException: Existing transaction found for transaction marked with propagation 'never'at org.springframework.transaction.support.AbstractPlatformTransactionManager.handleExistingTransaction(AbstractPlatformTransactionManager.java:430)at org.springframework.transaction.support.AbstractPlatformTransactionManager.getTransaction(AbstractPlatformTransactionManager.java:362)at org.springframework.transaction.interceptor.TransactionAspectSupport.createTransactionIfNecessary(TransactionAspectSupport.java:595)at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:374)at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:118)at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:205)at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:219)at com.sun.proxy.$Proxy23.addArea(Unknown Source)at com.morris.spring.service.TransactionService.addGoodAndArea(TransactionService.java:20)总结：AreaServiceImpl.addArea()执行时存在事务就会抛出异常。
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REQUIRED类似的操作。
配置如下：
TransactionService：REQUIRED
GoodServiceImpl：NESTED
AreaServiceImpl：NESTED
运行结果如下：
// 创建第一个事务EBUG DataSourceTransactionManager:381 - Creating new transaction with name [com.morris.spring.service.TransactionService.addGoodAndArea]: PROPAGATION_REQUIRED,ISOLATION_DEFAULT// 创建第一个连接DEBUG DriverManagerDataSource:144 - Creating new JDBC DriverManager Connection to [jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&allowMultiQueries=true&characterEncoding=UTF-8&useFastDateParsing=false&zeroDateTimeBehavior=convertToNull]DEBUG DataSourceTransactionManager:265 - Acquired Connection [com.mysql.cj.jdbc.ConnectionImpl@8ef162] for JDBC transactionDEBUG DataSourceTransactionManager:283 - Switching JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@8ef162] to manual commit------addGoodAndArea-------// 创建回滚点DEBUG DataSourceTransactionManager:466 - Creating nested transaction with name [com.morris.spring.service.AreaServiceImpl.addArea]DEBUG JdbcTemplate:860 - Executing prepared SQL updateDEBUG JdbcTemplate:609 - Executing prepared SQL statement [insert into t_area(area_name, area_code) values(?,?)]// 释放回滚点DEBUG DataSourceTransactionManager:754 - Releasing transaction savepoint// 创建回滚点DEBUG DataSourceTransactionManager:466 - Creating nested transaction with name [com.morris.spring.service.GoodServiceImpl.addGood]DEBUG JdbcTemplate:860 - Executing prepared SQL updateDEBUG JdbcTemplate:609 - Executing prepared SQL statement [insert into t_good(good_name, price) values(?,?)]// 释放回滚点DEBUG DataSourceTransactionManager:754 - Releasing transaction savepointDEBUG DataSourceTransactionManager:763 - Initiating transaction commitDEBUG DataSourceTransactionManager:329 - Committing JDBC transaction on Connection [com.mysql.cj.jdbc.ConnectionImpl@8ef162]DEBUG DataSourceTransactionManager:390 - Releasing JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@8ef162] after transaction如果不抛出异常，使用REQUIRED与NESTED都差不多，区别在于发生异常，下面演示REQUIRED与NESTED发生异常时的区别：
配置如下：
TransactionService：REQUIRED
AreaServiceImpl：REQUIRED
GoodServiceImpl：REQUIRED
TransactionService.addGoodAndArea修改如下：
@Transactional(propagation = Propagation.REQUIRED)public void addGoodAndArea() {System.out.println("------addGoodAndArea-------");try {areaService.addArea(0);} catch (Exception e) {e.printStackTrace();}goodService.addGood();}运行结果如下：
DEBUG DataSourceTransactionManager:381 - Creating new transaction with name [com.morris.spring.service.TransactionService.addGoodAndArea]: PROPAGATION_REQUIRED,ISOLATION_DEFAULTDEBUG DriverManagerDataSource:144 - Creating new JDBC DriverManager Connection to [jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&allowMultiQueries=true&characterEncoding=UTF-8&useFastDateParsing=false&zeroDateTimeBehavior=convertToNull]DEBUG DataSourceTransactionManager:265 - Acquired Connection [com.mysql.cj.jdbc.ConnectionImpl@f9aa66] for JDBC transactionDEBUG DataSourceTransactionManager:283 - Switching JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@f9aa66] to manual commit------addGoodAndArea-------DEBUG DataSourceTransactionManager:487 - Participating in existing transactionDEBUG DataSourceTransactionManager:877 - Participating transaction failed - marking existing transaction as rollback-onlyDEBUG DataSourceTransactionManager:360 - Setting JDBC transaction [com.mysql.cj.jdbc.ConnectionImpl@f9aa66] rollback-onlyjava.lang.ArithmeticException: / by zeroat com.morris.spring.service.AreaServiceImpl.addArea(AreaServiceImpl.java:18)... ...DEBUG DataSourceTransactionManager:487 - Participating in existing transactionDEBUG JdbcTemplate:860 - Executing prepared SQL updateDEBUG JdbcTemplate:609 - Executing prepared SQL statement [insert into t_good(good_name, price) values(?,?)]DEBUG DataSourceTransactionManager:723 - Global transaction is marked as rollback-only but transactional code requested commitDEBUG DataSourceTransactionManager:877 - Participating transaction failed - marking existing transaction as rollback-onlyDEBUG DataSourceTransactionManager:360 - Setting JDBC transaction [com.mysql.cj.jdbc.ConnectionImpl@f9aa66] rollback-onlyDEBUG DataSourceTransactionManager:723 - Global transaction is marked as rollback-only but transactional code requested commitDEBUG DataSourceTransactionManager:864 - Initiating transaction rollbackDEBUG DataSourceTransactionManager:345 - Rolling back JDBC transaction on Connection [com.mysql.cj.jdbc.ConnectionImpl@f9aa66]DEBUG DataSourceTransactionManager:390 - Releasing JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@f9aa66] after transactionorg.springframework.transaction.UnexpectedRollbackException: Transaction rolled back because it has been marked as rollback-onlyat org.springframework.transaction.support.AbstractPlatformTransactionManager.processRollback(AbstractPlatformTransactionManager.java:905)... ...从运行结果可以发现事务全部都回滚了。
将上面的配置修改如下：
TransactionService：REQUIRED
AreaServiceImpl：NESTED
GoodServiceImpl：NESTED
运行结果如下：
DEBUG DataSourceTransactionManager:381 - Creating new transaction with name [com.morris.spring.service.TransactionService.addGoodAndArea]: PROPAGATION_REQUIRED,ISOLATION_DEFAULTDEBUG DriverManagerDataSource:144 - Creating new JDBC DriverManager Connection to [jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&allowMultiQueries=true&characterEncoding=UTF-8&useFastDateParsing=false&zeroDateTimeBehavior=convertToNull]DEBUG DataSourceTransactionManager:265 - Acquired Connection [com.mysql.cj.jdbc.ConnectionImpl@8ef162] for JDBC transactionDEBUG DataSourceTransactionManager:283 - Switching JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@8ef162] to manual commit------addGoodAndArea-------DEBUG DataSourceTransactionManager:466 - Creating nested transaction with name [com.morris.spring.service.AreaServiceImpl.addArea]DEBUG DataSourceTransactionManager:857 - Rolling back transaction to savepointjava.lang.ArithmeticException: / by zeroat com.morris.spring.service.AreaServiceImpl.addArea(AreaServiceImpl.java:18)... ...DEBUG DataSourceTransactionManager:466 - Creating nested transaction with name [com.morris.spring.service.GoodServiceImpl.addGood]DEBUG JdbcTemplate:860 - Executing prepared SQL updateDEBUG JdbcTemplate:609 - Executing prepared SQL statement [insert into t_good(good_name, price) values(?,?)]DEBUG DataSourceTransactionManager:754 - Releasing transaction savepointDEBUG DataSourceTransactionManager:763 - Initiating transaction commitDEBUG DataSourceTransactionManager:329 - Committing JDBC transaction on Connection [com.mysql.cj.jdbc.ConnectionImpl@8ef162]DEBUG DataSourceTransactionManager:390 - Releasing JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@8ef162] after transaction从运行结果可以发现areaService.addArea()回滚了（本来就没有提交内容），goodService.addGood()的内容提交了。
注意只有运行时异常以及rollbakcFor指定的异常才会回滚。
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