前言

spring事务失效场景可能大家在很多文章都看过了，所以今天就水一篇，看大家能不能收获一些不一样的东西。直接进入主题

spring事务失效场景以及原因

1、场景一：service没有托管给spring

public class TranInvalidCaseWithoutInjectSpring {

    private UserService userService;

    public TranInvalidCaseWithoutInjectSpring(UserService userService) {
        this.userService = userService;
    }

    @Transactional
    public boolean add(User user){
        boolean isSuccess = userService.save(user);
        int i = 1 % 0;
        return isSuccess;
    }
}

    @Test
    public void testServiceWithoutInjectSpring(){
        boolean randomBoolean = new Random().nextBoolean();
        TranInvalidCaseWithoutInjectSpring tranInvalidCaseWithoutInjectSpring;
        if(randomBoolean){
            tranInvalidCaseWithoutInjectSpring = applicationContext.getBean(TranInvalidCaseWithoutInjectSpring.class);
            System.out.println("service已经被spring托管");
        }else{
            tranInvalidCaseWithoutInjectSpring = new TranInvalidCaseWithoutInjectSpring(userService);
            System.out.println("service没被spring托管");
        }

        boolean isSuccess = tranInvalidCaseWithoutInjectSpring.add(user);
        Assert.assertTrue(isSuccess);

    }

失效原因： spring事务生效的前提是，service必须是一个bean对象
解决方案： 将service注入spring

2、场景二：抛出受检异常

@Service
public class TranInvalidCaseByThrowCheckException {

    @Autowired
    private UserService userService;


    @Transactional
    public boolean add(User user) throws FileNotFoundException {
        boolean isSuccess = userService.save(user);
        new FileInputStream("1.txt");
        return isSuccess;
    }
    }

 @Test
    public void testThrowCheckException() throws Exception{
        boolean randomBoolean = new Random().nextBoolean();
        boolean isSuccess = false;
        TranInvalidCaseByThrowCheckException tranInvalidCaseByThrowCheckException = applicationContext.getBean(TranInvalidCaseByThrowCheckException.class);
        if(randomBoolean){
            System.out.println("配置@Transactional(rollbackFor = Exception.class)");
            isSuccess = tranInvalidCaseByThrowCheckException.save(user);
        }else{
            System.out.println("配置@Transactional");
            tranInvalidCaseByThrowCheckException.add(user);
        }

        Assert.assertTrue(isSuccess);

    }

失效原因： spring默认只会回滚非检查异常和error异常
解决方案： 配置rollbackFor

3、场景三：业务自己捕获了异常

 @Transactional
    public boolean add(User user) {
        boolean isSuccess = userService.save(user);
        try {
            int i = 1 % 0;
        } catch (Exception e) {

        }
        return isSuccess;
    }

  @Test
    public void testCatchExecption() throws Exception{
        boolean randomBoolean = new Random().nextBoolean();
        boolean isSuccess = false;
        TranInvalidCaseWithCatchException tranInvalidCaseByThrowCheckException = applicationContext.getBean(TranInvalidCaseWithCatchException.class);
        if(randomBoolean){
            randomBoolean = new Random().nextBoolean();
            if(randomBoolean){
                System.out.println("将异常原样抛出");
                tranInvalidCaseByThrowCheckException.save(user);
            }else{
                System.out.println("设置TransactionAspectSupport.currentTransactionStatus().setRollbackOnly();");
                tranInvalidCaseByThrowCheckException.addWithRollBack(user);
            }
        }else{
            System.out.println("业务自己捕获了异常");
            tranInvalidCaseByThrowCheckException.add(user);
        }

        Assert.assertTrue(isSuccess);

    }

失效原因： spring事务只有捕捉到了业务抛出去的异常，才能进行后续的处理，如果业务自己捕获了异常，则事务无法感知
解决方案：
1、将异常原样抛出；
2、设置TransactionAspectSupport.currentTransactionStatus().setRollbackOnly();

4、场景四：切面顺序导致

@Service
public class TranInvalidCaseWithAopSort {

    @Autowired
    private UserService userService;

    @Transactional
    public boolean save(User user) {
        boolean isSuccess = userService.save(user);
        try {
            int i = 1 % 0;
        } catch (Exception e) {
            throw new RuntimeException();
        }
        return isSuccess;
    }



}

@Aspect
@Component
@Slf4j
public class AopAspect {


    @Around(value = " execution (* com.github.lybgeek.transcase.aopsort..*.*(..))")
    public Object around(ProceedingJoinPoint pjp){

        try {
            System.out.println("这是一个切面");
           return pjp.proceed();
        } catch (Throwable throwable) {
            log.error("{}",throwable);
        }

        return null;
    }
}

失效原因： spring事务切面的优先级顺序最低，但如果自定义的切面优先级和他一样，且自定义的切面没有正确处理异常，则会同业务自己捕获异常的那种场景一样
解决方案：
1、在切面中将异常原样抛出；
2、在切面中设置TransactionAspectSupport.currentTransactionStatus().setRollbackOnly();

5、场景五：非public方法

@Service
public class TranInvalidCaseWithAccessPerm {

        @Autowired
        private UserService userService;

        @Transactional
        protected boolean save(User user){
            boolean isSuccess = userService.save(user);
            try {
                int i = 1 % 0;
            } catch (Exception e) {
                throw new RuntimeException();
            }
            return isSuccess;
        }

}

public class TranInvalidCaseWithAccessPermTest {

    public static void main(String[] args) {
        ConfigurableApplicationContext context = SpringApplication.run(Application.class);
        TranInvalidCaseWithAccessPerm tranInvalidCaseWithAccessPerm = context.getBean(TranInvalidCaseWithAccessPerm.class);
        boolean isSuccess = tranInvalidCaseWithAccessPerm.save(UserUtils.getUser());

        System.out.println(isSuccess);

    }
}

失效原因： spring事务默认生效的方法权限都必须为public

解决方案：
1、将方法改为public；
2、修改TansactionAttributeSource,将publicMethodsOnly改为false【这个从源码跟踪得出结论】
3、开启 AspectJ 代理模式【从spring文档得出结论】

文档如下

Method visibility and @Transactional
When using proxies, you should apply the @Transactional annotation only to methods with public visibility. If you do annotate protected, private or package-visible methods with the @Transactional annotation, no error is raised, but the annotated method does not exhibit the configured transactional settings. Consider the use of AspectJ (see below) if you need to annotate non-public methods.

具体步骤：

1、在pom引入aspectjrt坐标以及相应插件

<dependency>
	<groupId>org.aspectj</groupId>
	<artifactId>aspectjrt</artifactId>
	<version>1.8.9</version>
</dependency>

<plugin>
	<groupId>org.codehaus.mojo</groupId>
	<artifactId>aspectj-maven-plugin</artifactId>
	<version>1.9</version>
	<configuration>
		<showWeaveInfo>true</showWeaveInfo>
		<aspectLibraries>
			<aspectLibrary>
			<groupId>org.springframework</groupId>
			<artifactId>spring-aspects</artifactId>
			</aspectLibrary>
		</aspectLibraries>
	</configuration>
	<executions>
		<execution>
			 <goals>
              <goal>compile</goal>       <!-- use this goal to weave all your main classes -->
              <goal>test-compile</goal>  <!-- use this goal to weave all your test classes -->
            </goals>
		</execution>
	</executions>
</plugin> 

2、在启动类上加上如下配置

@EnableTransactionManagement(mode = AdviceMode.ASPECTJ)

注： 如果是在idea上运行，则需做如下配置

4、直接用TransactionTemplate

示例：

    @Autowired
    private TransactionTemplate transactionTemplate;

    private void process(){
        transactionTemplate.execute(new TransactionCallbackWithoutResult() {
            @Override
            protected void doInTransactionWithoutResult(TransactionStatus status) {
                processInTransaction();
            }
        });

    }

6、场景六：父子容器

失效原因： 子容器扫描范围过大，将未加事务配置的serivce扫描进来

解决方案：
1、父子容器个扫个的范围；
2、不用父子容器，所有bean都交给同一容器管理

注： 因为示例是使用springboot，而springboot启动默认没有父子容器,只有一个容器，因此就该场景就演示示例了

7、场景七：方法用final修饰

    @Transactional
    public final boolean add(User user, UserService userService) {
        boolean isSuccess = userService.save(user);
        try {
            int i = 1 % 0;
        } catch (Exception e) {
            throw new RuntimeException();
        }
        return isSuccess;
    }

失效原因： 因为spring事务是用动态代理实现，因此如果方法使用了final修饰，则代理类无法对目标方法进行重写，植入事务功能

解决方案：
1、方法不要用final修饰

8、场景八：方法用static修饰

  @Transactional
    public static boolean save(User user, UserService userService) {
        boolean isSuccess = userService.save(user);
        try {
            int i = 1 % 0;
        } catch (Exception e) {
            throw new RuntimeException();
        }
        return isSuccess;
    }

失效原因： 原因和final一样

解决方案：
1、方法不要用static修饰

9、场景九：调用本类方法

   public boolean save(User user) {
        return this.saveUser(user);
    }

    @Transactional
    public boolean saveUser(User user) {
        boolean isSuccess = userService.save(user);
        try {
            int i = 1 % 0;
        } catch (Exception e) {
            throw new RuntimeException();
        }
        return isSuccess;
    }

失效原因： 本类方法不经过代理，无法进行增强

解决方案：
1、注入自己来调用；
2、使用@EnableAspectJAutoProxy(exposeProxy = true) + AopContext.currentProxy()

10、场景十：多线程调用

 @Transactional(rollbackFor = Exception.class)
    public boolean save(User user) throws ExecutionException, InterruptedException {

        Future<Boolean> future = executorService.submit(() -> {
            boolean isSuccess = userService.save(user);
            try {
                int i = 1 % 0;
            } catch (Exception e) {
                throw new Exception();
            }
            return isSuccess;
        });
        return future.get();


    }

失效原因： 因为spring的事务是通过数据库连接来实现，而数据库连接spring是放在threadLocal里面。同一个事务，只能用同一个数据库连接。而多线程场景下，拿到的数据库连接是不一样的，即是属于不同事务

11、场景十一：错误的传播行为

 @Transactional(propagation = Propagation.NOT_SUPPORTED)
    public boolean save(User user) {
        boolean isSuccess = userService.save(user);
        try {
            int i = 1 % 0;
        } catch (Exception e) {
            throw new RuntimeException();
        }
        return isSuccess;
    }

失效原因： 使用的传播特性不支持事务

12、场景十二：使用了不支持事务的存储引擎

失效原因： 使用了不支持事务的存储引擎。比如mysql中的MyISAM

13、场景十三：数据源没有配置事务管理器

注： 因为springboot，他默认已经开启事务管理器。org.springframework.boot.autoconfigure.jdbc.DataSourceTransactionManagerAutoConfiguration。因此示例略过

14、场景十四：被代理的类过早实例化

@Service
public class TranInvalidCaseInstantiatedTooEarly implements BeanPostProcessor , Ordered {

    @Autowired
    private UserService userService;


    @Transactional
    public boolean save(User user) {
        boolean isSuccess = userService.save(user);
        try {
            int i = 1 % 0;
        } catch (Exception e) {
            throw new RuntimeException();
        }
        return isSuccess;
    }

    @Override
    public int getOrder() {
        return 1;
    }
}

失效原因： 当代理类的实例化早于AbstractAutoProxyCreator后置处理器，就无法被AbstractAutoProxyCreator后置处理器增强

总结

本文列举了14种spring事务失效的场景，其实这14种里面有很多都是归根结底都是属于同一类问题引起，比如因为动态代理原因、方法限定符原因、异常类型原因等