使用杰克逊时出现春季批量序列化问题

Question

在将应用程序从Spring Boot 1.3.x升级到2.1.x时，我遇到了Spring Batch的问题。显然，Spring Batch 需要序列化其执行上下文，并且到目前为止使用了 XStream，但在版本历史记录中的某个时候切换到了 Jackson。

现在，我在运行作业时出现异常：

2019-10-08 15:50:58:630 ERROR [main] [:] o.s.b.c.j.AbstractJob [] Encountered fatal error executing job
org.springframework.batch.core.JobExecutionException: Flow execution ended unexpectedly
at org.springframework.batch.core.job.flow.FlowJob.doExecute(FlowJob.java:142) ~[spring-batch-core-4.1.2.RELEASE.jar:4.1.2.RELEASE]
at org.springframework.batch.core.job.AbstractJob.execute(AbstractJob.java:313) [spring-batch-core-4.1.2.RELEASE.jar:4.1.2.RELEASE]
at org.springframework.batch.core.launch.support.SimpleJobLauncher$1.run(SimpleJobLauncher.java:144) [spring-batch-core-4.1.2.RELEASE.jar:4.1.2.RELEASE]
at org.springframework.core.task.SyncTaskExecutor.execute(SyncTaskExecutor.java:50) [spring-core-5.1.10.RELEASE.jar:5.1.10.RELEASE]
at org.springframework.batch.core.launch.support.SimpleJobLauncher.run(SimpleJobLauncher.java:137) [spring-batch-core-4.1.2.RELEASE.jar:4.1.2.RELEASE]
[…]
Caused by: org.springframework.batch.core.job.flow.FlowExecutionException: Ended flow=synchronizeBasicCustomerJob at state=synchronizeBasicCustomerJob.writeJobIntoJobContextStep0 with exception
at org.springframework.batch.core.job.flow.support.SimpleFlow.resume(SimpleFlow.java:178) ~[spring-batch-core-4.1.2.RELEASE.jar:4.1.2.RELEASE]
at org.springframework.batch.core.job.flow.support.SimpleFlow.start(SimpleFlow.java:144) ~[spring-batch-core-4.1.2.RELEASE.jar:4.1.2.RELEASE]
at org.springframework.batch.core.job.flow.FlowJob.doExecute(FlowJob.java:136) ~[spring-batch-core-4.1.2.RELEASE.jar:4.1.2.RELEASE]
... 41 more
Caused by: java.lang.IllegalArgumentException: Could not serialize the execution context
at org.springframework.batch.core.repository.dao.JdbcExecutionContextDao.serializeContext(JdbcExecutionContextDao.java:306) ~[spring-batch-core-4.1.2.RELEASE.jar:4.1.2.RELEASE]
at org.springframework.batch.core.repository.dao.JdbcExecutionContextDao.updateExecutionContext(JdbcExecutionContextDao.java:146) ~[spring-batch-core-4.1.2.RELEASE.jar:4.1.2.RELEASE]
at org.springframework.batch.core.repository.support.SimpleJobRepository.updateExecutionContext(SimpleJobRepository.java:216) ~[spring-batch-core-4.1.2.RELEASE.jar:4.1.2.RELEASE]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_202]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_202]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_202]
at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_202]
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:343) ~[spring-aop-5.1.10.RELEASE.jar:5.1.10.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:198) ~[spring-aop-5.1.10.RELEASE.jar:5.1.10.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163) ~[spring-aop-5.1.10.RELEASE.jar:5.1.10.RELEASE]
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:295) ~[spring-tx-5.1.10.RELEASE.jar:5.1.10.RELEASE]
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:98) ~[spring-tx-5.1.10.RELEASE.jar:5.1.10.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.10.RELEASE.jar:5.1.10.RELEASE]
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:212) ~[spring-aop-5.1.10.RELEASE.jar:5.1.10.RELEASE]
at com.sun.proxy.$Proxy242.updateExecutionContext(Unknown Source) ~[?:?]
at org.springframework.batch.core.job.SimpleStepHandler.handleStep(SimpleStepHandler.java:159) ~[spring-batch-core-4.1.2.RELEASE.jar:4.1.2.RELEASE]
at org.springframework.batch.core.job.flow.JobFlowExecutor.executeStep(JobFlowExecutor.java:68) ~[spring-batch-core-4.1.2.RELEASE.jar:4.1.2.RELEASE]
at org.springframework.batch.core.job.flow.support.state.StepState.handle(StepState.java:67) ~[spring-batch-core-4.1.2.RELEASE.jar:4.1.2.RELEASE]
at org.springframework.batch.core.job.flow.support.SimpleFlow.resume(SimpleFlow.java:169) ~[spring-batch-core-4.1.2.RELEASE.jar:4.1.2.RELEASE]
at org.springframework.batch.core.job.flow.support.SimpleFlow.start(SimpleFlow.java:144) ~[spring-batch-core-4.1.2.RELEASE.jar:4.1.2.RELEASE]
at org.springframework.batch.core.job.flow.FlowJob.doExecute(FlowJob.java:136) ~[spring-batch-core-4.1.2.RELEASE.jar:4.1.2.RELEASE]
... 41 more
Caused by: com.fasterxml.jackson.databind.JsonMappingException: Infinite recursion (StackOverflowError) (through reference chain: org.springframework.batch.core.JobExecution["stepExecutions"]->java.util.Collections$UnmodifiableRandomAccessList[0]->org.springframework.batch.core.StepExecution["jobExecution"]->org.springframework.batch.core.JobExecution["stepExecutions"]->java.util.Collections$UnmodifiableRandomAccessList[0]->org.springframework.batch.core.StepExecution["jobExecution"]->org.springframework.batch.core.JobExecution["stepExecutions"]->java.util.Collections$UnmodifiableRandomAccessList[0]->org.springframework.batch.core.StepExecution["jobExecution"]->org.springframework.batch.core.JobExecution["stepExecutions"]->…

原因很简单：实体JobExecution有一个StepExecution的列表，StepExecution有一个对JobExecution的反向引用，这是循环的，这导致杰克逊抛出这个丑陋的错误。

此问题的推荐解决方案似乎是用杰克逊注释(@JsonManagedReference和@JsonBackReference(对要序列化的类进行注释。但在这种情况下这是不可能的，因为有问题的类是Spring Batch的。

另一种解决方案是配置另一个ExecutionContextSerializer，即XStreamExecutionContextStringSerializer。这个解决方案对我有用，但XStreamExecutionContextStringSerializer类已被弃用，我宁愿不使用该类。

其他人(迁移到 Spring Boot 2 并使用 Spring Batch 4(有相反的问题：在他们的情况下，持久执行上下文的反序列化失败，因为它是由 XStream 编写的，现在无法被 Jackson 读取。但就我而言，序列化失败了，所以这不是XStream和Jackson之间的兼容性问题。

我做错了什么？

Answer 1

正如我在评论部分所述，您可以使用 Jackson MixIns 来解决您的问题，因为您无法访问项目中的 spring batch 源代码。

它会像

public abstract class JobExecutionMixin {
@JsonManagedReference
private Collection<StepExecution> stepExecutions;
}

对于背面参考：

public abstract class StepExecutionsMixin {
@JsonBackReference
private final JobExecution jobExecution;
}

然后，你必须在 Spring 启动应用程序中实现 ObjectMapper bean，如下所示：

ObjectMapper mapper = new ObjectMapper();
mapper.addMixInAnnotations(org.springframework.batch.core.StepExecutions.class, StepExecutionsMixin.class);
mapper.addMixInAnnotations(org.springframework.batch.core.JobExecution.class, JobExecutionMixin.class);