UnexpectedRollbackException简单思考
2019-12-25 本文已影响0人
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简介：
事务一直以来都是一个老生常谈的话题，要想真正的把它搞懂，还是要看源码，然后再实践。后续我会继续研究spring事务源码这块，有心得的话，会记录下来和大家一起分享、学习讨论。我只是大致跟踪了一下spring事务从头到尾执行的流程，涉及到的代码具体细节，还没有细细研究，这篇文章仅仅以demo的形式验证了一些事务的常见疑问，和UnexpectedRollbackException这个异常抛出来的场景。
类图：
事务.jpg
场景1：
代码：
@Transactional
public void test01() {
jdbcTemplate.execute("insert into apple (name) values ('apple001')");
test03();
System.out.println("能走到这里么？");
}
public void test03() {
jdbcTemplate.execute("insert into apple (name) values (null)");
}
日志：
--- [nio-8082-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring DispatcherServlet 'dispatcherServlet'
--- [nio-8082-exec-1] o.s.web.servlet.DispatcherServlet : Initializing Servlet 'dispatcherServlet'
--- [nio-8082-exec-1] o.s.web.servlet.DispatcherServlet : Detected StandardServletMultipartResolver
--- [nio-8082-exec-1] o.s.web.servlet.DispatcherServlet : enableLoggingRequestDetails='false': request parameters and headers will be masked to prevent unsafe logging of potentially sensitive data
--- [nio-8082-exec-1] o.s.web.servlet.DispatcherServlet : Completed initialization in 4 ms
--- [nio-8082-exec-1] o.s.web.servlet.DispatcherServlet : GET "/apple", parameters={}
--- [nio-8082-exec-1] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped to com.hao.datasourcelearn.controller.DatasourceControllerTest#test01()
--- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Creating new transaction with name [com.hao.datasourcelearn.service.DatasourceJdbcTest.test01]: PROPAGATION_REQUIRED,ISOLATION_DEFAULT
--- [nio-8082-exec-1] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Starting...
--- [nio-8082-exec-1] com.zaxxer.hikari.util.DriverDataSource : Registered driver with driverClassName=com.mysql.jdbc.Driver was not found, trying direct instantiation.
--- [nio-8082-exec-1] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Start completed.
--- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Acquired Connection [HikariProxyConnection@963096416 wrapping com.mysql.cj.jdbc.ConnectionImpl@6c5c1e05] for JDBC transaction
--- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Switching JDBC Connection [HikariProxyConnection@963096416 wrapping com.mysql.cj.jdbc.ConnectionImpl@6c5c1e05] to manual commit
--- [nio-8082-exec-1] o.s.jdbc.core.JdbcTemplate : Executing SQL statement [insert into apple (name) values ('apple001')]
--- [nio-8082-exec-1] o.s.jdbc.core.JdbcTemplate : Executing SQL statement [insert into apple (name) values (null)]
--- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Initiating transaction rollback
--- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Rolling back JDBC transaction on Connection [HikariProxyConnection@963096416 wrapping com.mysql.cj.jdbc.ConnectionImpl@6c5c1e05]
--- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Releasing JDBC Connection [HikariProxyConnection@963096416 wrapping com.mysql.cj.jdbc.ConnectionImpl@6c5c1e05] after transaction
--- [nio-8082-exec-1] o.s.web.servlet.DispatcherServlet : Failed to complete request: org.springframework.dao.DataIntegrityViolationException: StatementCallback; SQL [insert into apple (name) values (null)]; Column 'name' cannot be null; nested exception is java.sql.SQLIntegrityConstraintViolationException: Column 'name' cannot be null
--- [nio-8082-exec-1] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.dao.DataIntegrityViolationException: StatementCallback; SQL [insert into apple (name) values (null)]; Column 'name' cannot be null; nested exception is java.sql.SQLIntegrityConstraintViolationException: Column 'name' cannot be null] with root cause
结果：
回滚
java.sql.SQLIntegrityConstraintViolationException: Column 'name' cannot be null
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:117) ~[mysql-connector-java-8.0.18.jar:8.0.18]
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97) ~[mysql-connector-java-8.0.18.jar:8.0.18]
at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:122) ~[mysql-connector-java-8.0.18.jar:8.0.18]
说明：
在同一个类里面的方法调用，test03方法的代码直接就运行在test01的事务里面，等价于把test03的代码直接放到test01里面。
场景2：
代码：
@Transactional
public void test01() {
jdbcTemplate.execute("insert into apple (name) values ('apple001')");
test03();
System.out.println("能走到这里么？");
}
@Transactional(propagation = Propagation.REQUIRES_NEW)
public void test03() {
jdbcTemplate.execute("insert into apple (name) values (null)");
}
日志：
--- [nio-8082-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring DispatcherServlet 'dispatcherServlet'
--- [nio-8082-exec-1] o.s.web.servlet.DispatcherServlet : Initializing Servlet 'dispatcherServlet'
--- [nio-8082-exec-1] o.s.web.servlet.DispatcherServlet : Detected StandardServletMultipartResolver
--- [nio-8082-exec-1] o.s.web.servlet.DispatcherServlet : enableLoggingRequestDetails='false': request parameters and headers will be masked to prevent unsafe logging of potentially sensitive data
--- [nio-8082-exec-1] o.s.web.servlet.DispatcherServlet : Completed initialization in 4 ms
--- [nio-8082-exec-1] o.s.web.servlet.DispatcherServlet : GET "/apple", parameters={}
--- [nio-8082-exec-1] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped to com.hao.datasourcelearn.controller.DatasourceControllerTest#test01()
--- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Creating new transaction with name [com.hao.datasourcelearn.service.DatasourceJdbcTest.test01]: PROPAGATION_REQUIRED,ISOLATION_DEFAULT
--- [nio-8082-exec-1] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Starting...
--- [nio-8082-exec-1] com.zaxxer.hikari.util.DriverDataSource : Registered driver with driverClassName=com.mysql.jdbc.Driver was not found, trying direct instantiation.
--- [nio-8082-exec-1] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Start completed.
--- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Acquired Connection [HikariProxyConnection@491071113 wrapping com.mysql.cj.jdbc.ConnectionImpl@73cdc2a4] for JDBC transaction
--- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Switching JDBC Connection [HikariProxyConnection@491071113 wrapping com.mysql.cj.jdbc.ConnectionImpl@73cdc2a4] to manual commit
--- [nio-8082-exec-1] o.s.jdbc.core.JdbcTemplate : Executing SQL statement [insert into apple (name) values ('apple001')]
--- [nio-8082-exec-1] o.s.jdbc.core.JdbcTemplate : Executing SQL statement [insert into apple (name) values (null)]
--- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Initiating transaction rollback
--- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Rolling back JDBC transaction on Connection [HikariProxyConnection@491071113 wrapping com.mysql.cj.jdbc.ConnectionImpl@73cdc2a4]
--- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Releasing JDBC Connection [HikariProxyConnection@491071113 wrapping com.mysql.cj.jdbc.ConnectionImpl@73cdc2a4] after transaction
--- [nio-8082-exec-1] o.s.web.servlet.DispatcherServlet : Failed to complete request: org.springframework.dao.DataIntegrityViolationException: StatementCallback; SQL [insert into apple (name) values (null)]; Column 'name' cannot be null; nested exception is java.sql.SQLIntegrityConstraintViolationException: Column 'name' cannot be null
--- [nio-8082-exec-1] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.dao.DataIntegrityViolationException: StatementCallback; SQL [insert into apple (name) values (null)]; Column 'name' cannot be null; nested exception is java.sql.SQLIntegrityConstraintViolationException: Column 'name' cannot be null] with root cause
结果：
回滚
java.sql.SQLIntegrityConstraintViolationException: Column 'name' cannot be null
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:117) ~[mysql-connector-java-8.0.18.jar:8.0.18]
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97) ~[mysql-connector-java-8.0.18.jar:8.0.18]
at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:122) ~[mysql-connector-java-8.0.18.jar:8.0.18]
说明：
在同一个service里面的方法之间的调用，是不牵涉到什么嵌套事务的，被调用方法上面的事务注解也不会生效的，因为spring的事务的实现机制是动态代理（CGlib），因为动态代理一般都是代理的类，只有通过service.test的形式调用，才有机会用到代理。
场景3：
代码：
@Service
public class DatasourceJdbcTest {
@Resource
private JdbcTemplate jdbcTemplate;
@Resource
private Test2 test2;
@Transactional
public void test01() {
jdbcTemplate.execute("insert into apple (name) values ('apple001')");
test2.test02();
System.out.println("能走到这里么？");
}
}
@Service
public class Test2 {
@Resource
private JdbcTemplate jdbcTemplate;
@Transactional
public void test02() {
jdbcTemplate.execute("insert into apple (name) values (null)");
}
}
日志：
--- [nio-8082-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring DispatcherServlet 'dispatcherServlet'
--- [nio-8082-exec-1] o.s.web.servlet.DispatcherServlet : Initializing Servlet 'dispatcherServlet'
--- [nio-8082-exec-1] o.s.web.servlet.DispatcherServlet : Detected StandardServletMultipartResolver
--- [nio-8082-exec-1] o.s.web.servlet.DispatcherServlet : enableLoggingRequestDetails='false': request parameters and headers will be masked to prevent unsafe logging of potentially sensitive data
--- [nio-8082-exec-1] o.s.web.servlet.DispatcherServlet : Completed initialization in 5 ms
--- [nio-8082-exec-1] o.s.web.servlet.DispatcherServlet : GET "/apple", parameters={}
--- [nio-8082-exec-1] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped to com.hao.datasourcelearn.controller.DatasourceControllerTest#test01()
--- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Creating new transaction with name [com.hao.datasourcelearn.service.DatasourceJdbcTest.test01]: PROPAGATION_REQUIRED,ISOLATION_DEFAULT
--- [nio-8082-exec-1] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Starting...
--- [nio-8082-exec-1] com.zaxxer.hikari.util.DriverDataSource : Registered driver with driverClassName=com.mysql.jdbc.Driver was not found, trying direct instantiation.
--- [nio-8082-exec-1] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Start completed.
--- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Acquired Connection [HikariProxyConnection@1973985077 wrapping com.mysql.cj.jdbc.ConnectionImpl@1ce42990] for JDBC transaction
--- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Switching JDBC Connection [HikariProxyConnection@1973985077 wrapping com.mysql.cj.jdbc.ConnectionImpl@1ce42990] to manual commit
--- [nio-8082-exec-1] o.s.jdbc.core.JdbcTemplate : Executing SQL statement [insert into apple (name) values ('apple001')]
--- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Participating in existing transaction
--- [nio-8082-exec-1] o.s.jdbc.core.JdbcTemplate : Executing SQL statement [insert into apple (name) values (null)]
--- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Participating transaction failed - marking existing transaction as rollback-only
--- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Setting JDBC transaction [HikariProxyConnection@1973985077 wrapping com.mysql.cj.jdbc.ConnectionImpl@1ce42990] rollback-only
--- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Initiating transaction rollback
--- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Rolling back JDBC transaction on Connection [HikariProxyConnection@1973985077 wrapping com.mysql.cj.jdbc.ConnectionImpl@1ce42990]
--- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Releasing JDBC Connection [HikariProxyConnection@1973985077 wrapping com.mysql.cj.jdbc.ConnectionImpl@1ce42990] after transaction
--- [nio-8082-exec-1] o.s.web.servlet.DispatcherServlet : Failed to complete request: org.springframework.dao.DataIntegrityViolationException: StatementCallback; SQL [insert into apple (name) values (null)]; Column 'name' cannot be null; nested exception is java.sql.SQLIntegrityConstraintViolationException: Column 'name' cannot be null
--- [nio-8082-exec-1] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.dao.DataIntegrityViolationException: StatementCallback; SQL [insert into apple (name) values (null)]; Column 'name' cannot be null; nested exception is java.sql.SQLIntegrityConstraintViolationException: Column 'name' cannot be null] with root cause
结果：
回滚
java.sql.SQLIntegrityConstraintViolationException: Column 'name' cannot be null
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:117) ~[mysql-connector-java-8.0.18.jar:8.0.18]
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97) ~[mysql-connector-java-8.0.18.jar:8.0.18]
at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:122) ~[mysql-connector-java-8.0.18.jar:8.0.18]
说明：
这个例子涉及到不同service的方法调用，就会涉及到嵌套事务了，由于两个方法上面的事务注解都是@Transactional，所以test02方法会运行在test01的事务里面，从日志里面也可以看的出来，Participating in existing transaction这句话就印证了。这里抛出的异常依然是SQLIntegrityConstraintViolationException，还没有抛出UnexpectedRollbackException这个异常，System.out.println("能走到这里么？")，这句话也木有打印证明test01没有执行到这里，就被test02抛出的异常打断了。
场景4：
代码：
@Service
public class DatasourceJdbcTest {
@Resource
private JdbcTemplate jdbcTemplate;
@Resource
private Test2 test2;
@Transactional
public void test01() {
jdbcTemplate.execute("insert into apple (name) values ('apple001')");
test2.test02();
System.out.println("能走到这里么？");
}
}
@Service
public class Test2 {
@Resource
private JdbcTemplate jdbcTemplate;
@Transactional
public void test02() {
try {
jdbcTemplate.execute("insert into apple (name) values (null)");
} catch (DataAccessException e) {
System.out.println("插入数据库出错！");;
}
}
}
日志：
2019-12-25 19:45:22.653 INFO 32704 --- [nio-8082-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring DispatcherServlet 'dispatcherServlet'
2019-12-25 19:45:22.653 INFO 32704 --- [nio-8082-exec-1] o.s.web.servlet.DispatcherServlet : Initializing Servlet 'dispatcherServlet'
2019-12-25 19:45:22.653 DEBUG 32704 --- [nio-8082-exec-1] o.s.web.servlet.DispatcherServlet : Detected StandardServletMultipartResolver
2019-12-25 19:45:22.657 DEBUG 32704 --- [nio-8082-exec-1] o.s.web.servlet.DispatcherServlet : enableLoggingRequestDetails='false': request parameters and headers will be masked to prevent unsafe logging of potentially sensitive data
2019-12-25 19:45:22.657 INFO 32704 --- [nio-8082-exec-1] o.s.web.servlet.DispatcherServlet : Completed initialization in 4 ms
2019-12-25 19:45:22.661 DEBUG 32704 --- [nio-8082-exec-1] o.s.web.servlet.DispatcherServlet : GET "/apple", parameters={}
2019-12-25 19:45:22.663 DEBUG 32704 --- [nio-8082-exec-1] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped to com.hao.datasourcelearn.controller.DatasourceControllerTest#test01()
2019-12-25 19:45:22.671 DEBUG 32704 --- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Creating new transaction with name [com.hao.datasourcelearn.service.DatasourceJdbcTest.test01]: PROPAGATION_REQUIRED,ISOLATION_DEFAULT
2019-12-25 19:45:22.671 INFO 32704 --- [nio-8082-exec-1] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Starting...
2019-12-25 19:45:22.672 WARN 32704 --- [nio-8082-exec-1] com.zaxxer.hikari.util.DriverDataSource : Registered driver with driverClassName=com.mysql.jdbc.Driver was not found, trying direct instantiation.
2019-12-25 19:45:22.746 INFO 32704 --- [nio-8082-exec-1] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Start completed.
2019-12-25 19:45:22.747 DEBUG 32704 --- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Acquired Connection [HikariProxyConnection@207098194 wrapping com.mysql.cj.jdbc.ConnectionImpl@7350e8d1] for JDBC transaction
2019-12-25 19:45:22.748 DEBUG 32704 --- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Switching JDBC Connection [HikariProxyConnection@207098194 wrapping com.mysql.cj.jdbc.ConnectionImpl@7350e8d1] to manual commit
2019-12-25 19:45:22.752 DEBUG 32704 --- [nio-8082-exec-1] o.s.jdbc.core.JdbcTemplate : Executing SQL statement [insert into apple (name) values ('apple001')]
2019-12-25 19:45:22.758 DEBUG 32704 --- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Participating in existing transaction
2019-12-25 19:45:22.760 DEBUG 32704 --- [nio-8082-exec-1] o.s.jdbc.core.JdbcTemplate : Executing SQL statement [insert into apple (name) values (null)]
插入数据库出错！
能走到这里么？
2019-12-25 19:45:22.825 DEBUG 32704 --- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Initiating transaction commit
2019-12-25 19:45:22.825 DEBUG 32704 --- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Committing JDBC transaction on Connection [HikariProxyConnection@207098194 wrapping com.mysql.cj.jdbc.ConnectionImpl@7350e8d1]
2019-12-25 19:45:22.830 DEBUG 32704 --- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Releasing JDBC Connection [HikariProxyConnection@207098194 wrapping com.mysql.cj.jdbc.ConnectionImpl@7350e8d1] after transaction
结果：
commit
说明：
test01和test02的注解都是@Transactional，从日志上看，依然是同一个事务，如果test02捕获自己的异常，自己消化掉，那么整个事务就不会受到异常的影响，会commit。
场景5：
代码：
@Service
public class DatasourceJdbcTest {
@Resource
private JdbcTemplate jdbcTemplate;
@Resource
private Test2 test2;
@Transactional
public void test01() {
jdbcTemplate.execute("insert into apple (name) values ('apple001')");
try {
test2.test02();
} catch (Exception e) {
System.out.println("捕获到test02的异常");;
}
System.out.println("能走到这里么？");
}
}
@Service
public class Test2 {
@Resource
private JdbcTemplate jdbcTemplate;
@Transactional
public void test02() {
jdbcTemplate.execute("insert into apple (name) values (null)");
}
}
日志：
--- [nio-8082-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring DispatcherServlet 'dispatcherServlet'
--- [nio-8082-exec-1] o.s.web.servlet.DispatcherServlet : Initializing Servlet 'dispatcherServlet'
--- [nio-8082-exec-1] o.s.web.servlet.DispatcherServlet : Detected StandardServletMultipartResolver
--- [nio-8082-exec-1] o.s.web.servlet.DispatcherServlet : enableLoggingRequestDetails='false': request parameters and headers will be masked to prevent unsafe logging of potentially sensitive data
--- [nio-8082-exec-1] o.s.web.servlet.DispatcherServlet : Completed initialization in 5 ms
--- [nio-8082-exec-1] o.s.web.servlet.DispatcherServlet : GET "/apple", parameters={}
--- [nio-8082-exec-1] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped to com.hao.datasourcelearn.controller.DatasourceControllerTest#test01()
--- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Creating new transaction with name [com.hao.datasourcelearn.service.DatasourceJdbcTest.test01]: PROPAGATION_REQUIRED,ISOLATION_DEFAULT
--- [nio-8082-exec-1] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Starting...
--- [nio-8082-exec-1] com.zaxxer.hikari.util.DriverDataSource : Registered driver with driverClassName=com.mysql.jdbc.Driver was not found, trying direct instantiation.
--- [nio-8082-exec-1] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Start completed.
--- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Acquired Connection [HikariProxyConnection@792507397 wrapping com.mysql.cj.jdbc.ConnectionImpl@301132b8] for JDBC transaction
--- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Switching JDBC Connection [HikariProxyConnection@792507397 wrapping com.mysql.cj.jdbc.ConnectionImpl@301132b8] to manual commit
--- [nio-8082-exec-1] o.s.jdbc.core.JdbcTemplate : Executing SQL statement [insert into apple (name) values ('apple001')]
--- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Participating in existing transaction
--- [nio-8082-exec-1] o.s.jdbc.core.JdbcTemplate : Executing SQL statement [insert into apple (name) values (null)]
--- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Participating transaction failed - marking existing transaction as rollback-only
--- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Setting JDBC transaction [HikariProxyConnection@792507397 wrapping com.mysql.cj.jdbc.ConnectionImpl@301132b8] rollback-only
捕获到test02的异常
能走到这里么？
--- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Global transaction is marked as rollback-only but transactional code requested commit
--- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Initiating transaction rollback
--- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Rolling back JDBC transaction on Connection [HikariProxyConnection@792507397 wrapping com.mysql.cj.jdbc.ConnectionImpl@301132b8]
--- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Releasing JDBC Connection [HikariProxyConnection@792507397 wrapping com.mysql.cj.jdbc.ConnectionImpl@301132b8] after transaction
--- [nio-8082-exec-1] o.s.web.servlet.DispatcherServlet : Failed to complete request: org.springframework.transaction.UnexpectedRollbackException: Transaction rolled back because it has been marked as rollback-only
--- [nio-8082-exec-1] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.transaction.UnexpectedRollbackException: Transaction rolled back because it has been marked as rollback-only] with root cause
结果：
回滚
org.springframework.transaction.UnexpectedRollbackException: Transaction rolled back because it has been marked as rollback-only
at org.springframework.transaction.support.AbstractPlatformTransactionManager.processRollback(AbstractPlatformTransactionManager.java:871) ~[spring-tx-5.2.2.RELEASE.jar:5.2.2.RELEASE]
at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:708) ~[spring-tx-5.2.2.RELEASE.jar:5.2.2.RELEASE]
at org.springframework.transaction.interceptor.TransactionAspectSupport.commitTransactionAfterReturning(TransactionAspectSupport.java:631) ~[spring-tx-5.2.2.RELEASE.jar:5.2.2.RELEASE]
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:385) ~[spring-tx-5.2.2.RELEASE.jar:5.2.2.RELEASE]
说明：
UnexpectedRollbackException这个异常出现了，当test02不捕获test01异常的时候，不会抛出这个异常，是因为程序直接就被异常打断了，不会执行commit方法,而这个异常的抛出就是在commit方法里面，但是当test02捕获test01异常的时候，神奇的事情出现了，这个异常出现了，为啥呢？下面是个人看代码的理解：从日志来看Participating in existing transaction依然是只有一个事务，但是可以逻辑上分为外层和内层事务。
从代码上看，其实这个异常是由unexpectedRollback这个属性值来控制的，为true就会抛出目标异常，而什么情况下为true呢，当test02捕获test01异常的时候，当内外层事务都执行完的时候，程序会执行commit操作，这commit操作里面会以参数的形式直接传个true：processRollback(defStatus, true);：关键就是这个true参数起到了关键作用，这篇文章不分析具体的细节，只是说明一下大概，具体的事务代码详细分析，后续会陆续写一下的，感觉挺多的，还是一点一点的拆分着写比较好，一次写一个主题或者一段代码。
@Override
public final void commit(TransactionStatus status) throws TransactionException {
if (status.isCompleted()) {
throw new IllegalTransactionStateException(
"Transaction is already completed - do not call commit or rollback more than once per transaction");
}
DefaultTransactionStatus defStatus = (DefaultTransactionStatus) status;
if (defStatus.isLocalRollbackOnly()) {
if (defStatus.isDebug()) {
logger.debug("Transactional code has requested rollback");
}
processRollback(defStatus, false);
return;
}
if (!shouldCommitOnGlobalRollbackOnly() && defStatus.isGlobalRollbackOnly()) {
if (defStatus.isDebug()) {
logger.debug("Global transaction is marked as rollback-only but transactional code requested commit");
}
processRollback(defStatus, true);
return;
}
processCommit(defStatus);
}
其实从技术上来说如果想避免抛出这个异常UnexpectedRollbackException，有两种方法，首先这个场景一般都是在嵌套业务里面出现，那么我们可以在test02方法上面开启一个新事务，或者把test01的异常在test02方法上继续上抛，让框架处理。
场景6：
代码：
@Service
public class DatasourceJdbcTest {
@Resource
private JdbcTemplate jdbcTemplate;
@Resource
private Test2 test2;
@Transactional
public void test01() {
jdbcTemplate.execute("insert into apple (name) values ('apple001')");
try {
test2.test02();
} catch (Exception e) {
throw e;
}
System.out.println("能走到这里么？");
}
}
@Service
public class Test2 {
@Resource
private JdbcTemplate jdbcTemplate;
@Transactional
public void test02() {
jdbcTemplate.execute("insert into apple (name) values (null)");
}
}
日志：
--- [nio-8082-exec-2] o.s.web.servlet.DispatcherServlet : GET "/apple", parameters={}
--- [nio-8082-exec-2] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped to com.hao.datasourcelearn.controller.DatasourceControllerTest#test01()
--- [nio-8082-exec-2] o.s.j.d.DataSourceTransactionManager : Creating new transaction with name [com.hao.datasourcelearn.service.DatasourceJdbcTest.test01]: PROPAGATION_REQUIRED,ISOLATION_DEFAULT
--- [nio-8082-exec-2] o.s.j.d.DataSourceTransactionManager : Acquired Connection [HikariProxyConnection@1832385864 wrapping com.mysql.cj.jdbc.ConnectionImpl@301132b8] for JDBC transaction
--- [nio-8082-exec-2] o.s.j.d.DataSourceTransactionManager : Switching JDBC Connection [HikariProxyConnection@1832385864 wrapping com.mysql.cj.jdbc.ConnectionImpl@301132b8] to manual commit
--- [nio-8082-exec-2] o.s.jdbc.core.JdbcTemplate : Executing SQL statement [insert into apple (name) values ('apple001')]
--- [nio-8082-exec-2] o.s.j.d.DataSourceTransactionManager : Participating in existing transaction
--- [nio-8082-exec-2] o.s.jdbc.core.JdbcTemplate : Executing SQL statement [insert into apple (name) values (null)]
--- [nio-8082-exec-2] o.s.j.d.DataSourceTransactionManager : Participating transaction failed - marking existing transaction as rollback-only
--- [nio-8082-exec-2] o.s.j.d.DataSourceTransactionManager : Setting JDBC transaction [HikariProxyConnection@1832385864 wrapping com.mysql.cj.jdbc.ConnectionImpl@301132b8] rollback-only
--- [nio-8082-exec-2] o.s.j.d.DataSourceTransactionManager : Initiating transaction rollback
--- [nio-8082-exec-2] o.s.j.d.DataSourceTransactionManager : Rolling back JDBC transaction on Connection [HikariProxyConnection@1832385864 wrapping com.mysql.cj.jdbc.ConnectionImpl@301132b8]
--- [nio-8082-exec-2] o.s.j.d.DataSourceTransactionManager : Releasing JDBC Connection [HikariProxyConnection@1832385864 wrapping com.mysql.cj.jdbc.ConnectionImpl@301132b8] after transaction
--- [nio-8082-exec-2] o.s.web.servlet.DispatcherServlet : Failed to complete request: org.springframework.dao.DataIntegrityViolationException: StatementCallback; SQL [insert into apple (name) values (null)]; Column 'name' cannot be null; nested exception is java.sql.SQLIntegrityConstraintViolationException: Column 'name' cannot be null
--- [nio-8082-exec-2] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.dao.DataIntegrityViolationException: StatementCallback; SQL [insert into apple (name) values (null)]; Column 'name' cannot be null; nested exception is java.sql.SQLIntegrityConstraintViolationException: Column 'name' cannot be null] with root cause
结果：
回滚
java.sql.SQLIntegrityConstraintViolationException: Column 'name' cannot be null
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:117) ~[mysql-connector-java-8.0.18.jar:8.0.18]
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97) ~[mysql-connector-java-8.0.18.jar:8.0.18]
at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:122) ~[mysql-connector-java-8.0.18.jar:8.0.18]
at com.mysql.cj.jdbc.StatementImpl.executeInternal(StatementImpl.java:764) ~[mysql-connector-java-8.0.18.jar:8.0.18]
说明：
test02把这个异常抛出去，让框架捕获处理，test02后面的代码也不用执行了,也就不会执行后续的commit，不会抛出UnexpectedRollbackException。
场景7：
代码：
@Service
public class DatasourceJdbcTest {
@Resource
private JdbcTemplate jdbcTemplate;
@Resource
private Test2 test2;
@Transactional
public void test01() {
jdbcTemplate.execute("insert into apple (name) values ('apple001')");
test2.test02();
System.out.println("能走到这里么？");
}
}
@Service
public class Test2 {
@Resource
private JdbcTemplate jdbcTemplate;
@Transactional(propagation = Propagation.REQUIRES_NEW)
public void test02() {
jdbcTemplate.execute("insert into apple (name) values (null)");
}
}
日志：
--- [nio-8082-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring DispatcherServlet 'dispatcherServlet'
--- [nio-8082-exec-1] o.s.web.servlet.DispatcherServlet : Initializing Servlet 'dispatcherServlet'
--- [nio-8082-exec-1] o.s.web.servlet.DispatcherServlet : Detected StandardServletMultipartResolver
--- [nio-8082-exec-1] o.s.web.servlet.DispatcherServlet : enableLoggingRequestDetails='false': request parameters and headers will be masked to prevent unsafe logging of potentially sensitive data
--- [nio-8082-exec-1] o.s.web.servlet.DispatcherServlet : Completed initialization in 5 ms
--- [nio-8082-exec-1] o.s.web.servlet.DispatcherServlet : GET "/apple", parameters={}
--- [nio-8082-exec-1] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped to com.hao.datasourcelearn.controller.DatasourceControllerTest#test01()
--- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Creating new transaction with name [com.hao.datasourcelearn.service.DatasourceJdbcTest.test01]: PROPAGATION_REQUIRED,ISOLATION_DEFAULT
--- [nio-8082-exec-1] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Starting...
--- [nio-8082-exec-1] com.zaxxer.hikari.util.DriverDataSource : Registered driver with driverClassName=com.mysql.jdbc.Driver was not found, trying direct instantiation.
--- [nio-8082-exec-1] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Start completed.
--- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Acquired Connection [HikariProxyConnection@1410196551 wrapping com.mysql.cj.jdbc.ConnectionImpl@27bf96e7] for JDBC transaction
--- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Switching JDBC Connection [HikariProxyConnection@1410196551 wrapping com.mysql.cj.jdbc.ConnectionImpl@27bf96e7] to manual commit
--- [nio-8082-exec-1] o.s.jdbc.core.JdbcTemplate : Executing SQL statement [insert into apple (name) values ('apple001')]
--- [nio-8082-exec-1] o.s.j.d.DataSourceTransactionManager : Suspending current transaction, creating new transaction with name [com.hao.datasourcelearn.service.Test2.test02]
结果：
回滚
java.sql.SQLIntegrityConstraintViolationException: Column 'name' cannot be null
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:117) ~[mysql-connector-java-8.0.18.jar:8.0.18]
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97) ~[mysql-connector-java-8.0.18.jar:8.0.18]
at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:122) ~[mysql-connector-java-8.0.18.jar:8.0.18]
at com.mysql.cj.jdbc.StatementImpl.executeInternal(StatementImpl.java:764) ~[mysql-connector-java-8.0.18.jar:8.0.18]
at com.mysql.cj.jdbc.StatementImpl.execute(StatementImpl.java:648) ~[mysql-connector-java-8.0.18.jar:8.0.18]
说明：
从日志打印来看，Suspending current transaction, creating new transaction with name [com.hao.datasourcelearn.service.Test2.test02],是两个不同的事务，不是嵌套事务，虽然抛出异常，但是不会被marked as rollback-only，也就不会抛出UnexpectedRollbackException。但是这个异常会被抛出到父级test01里面，会影响test01的事务提交的。
总结：
这篇文章主要偏重于从例子上验证一些常见的疑问，没有对具体的源码进行分析，只是从代码的角度简单的解释了一下UnexpectedRollbackException产生的原因和场景。感觉读源码不容易呀，要想完全搞懂一个，确实需要很多精力和耐心，真的要死磕到底，才能有所收获，路漫漫其修远兮，吾将上下而求索，后面继续......欢迎大家指点错误，一起讨论，多多指教。觉察即自由。
