无法打开JPA EntityManager进行交易; 嵌套异常是java.lang.IllegalStateException

Question

我特别对Spring和Spring-Batch很新.我还是设法安装了Spring Batch-Admin.我添加了自定义作业和Hibernate/JPA以实现持久性.

一切都按预期工作,直到第一个块应该持久化.然后我收到以下错误消息:

org.springframework.transaction.CannotCreateTransactionException: 
      Could not open JPA  EntityManager for transaction;

nested exception is java.lang.IllegalStateException: Already value
      [org.springframework.jdbc.datasource.ConnectionHolder@60d31437] 
      for key [org.springframework.jdbc.datasource.DriverManagerDataSource@12da4b19] 
      bound to thread [jobLauncherTaskExecutor-1]

这是完整的堆栈跟踪:

org.springframework.transaction.CannotCreateTransactionException: Could not open JPA  EntityManager for transaction; nested exception is java.lang.IllegalStateException: Already value [org.springframework.jdbc.datasource.ConnectionHolder@43f9e588] for key [org.springframework.jdbc.datasource.DriverManagerDataSource@84f171a] bound to thread [jobLauncherTaskExecutor-1]
     at org.springframework.orm.jpa.JpaTransactionManager.doBegin(JpaTransactionManager.java:427)
     at org.springframework.transaction.support.AbstractPlatformTransactionManager.getTransaction(AbstractPlatformTransactionManager.java:371)
     at org.springframework.transaction.interceptor.TransactionAspectSupport.createTransactionIfNecessary(TransactionAspectSupport.java:335)
     at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:105)
     at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
     at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202)
     at com.sun.proxy.$Proxy41.saveIfUnique(Unknown Source)
     at com.qompa.batch.ArticleItemWriter.write(ArticleItemWriter.java:28)
     at org.springframework.batch.core.step.item.SimpleChunkProcessor.writeItems(SimpleChunkProcessor.java:171)
     at org.springframework.batch.core.step.item.SimpleChunkProcessor.doWrite(SimpleChunkProcessor.java:150)
     at org.springframework.batch.core.step.item.FaultTolerantChunkProcessor$3.doWithRetry(FaultTolerantChunkProcessor.java:313)
     at org.springframework.batch.retry.support.RetryTemplate.doExecute(RetryTemplate.java:240)
     at org.springframework.batch.retry.support.RetryTemplate.execute(RetryTemplate.java:187)
     at org.springframework.batch.core.step.item.BatchRetryTemplate.execute(BatchRetryTemplate.java:213)
     at org.springframework.batch.core.step.item.FaultTolerantChunkProcessor.write(FaultTolerantChunkProcessor.java:402)
     at org.springframework.batch.core.step.item.SimpleChunkProcessor.process(SimpleChunkProcessor.java:194)
     at org.springframework.batch.core.step.item.ChunkOrientedTasklet.execute(ChunkOrientedTasklet.java:74)
     at org.springframework.batch.core.step.tasklet.TaskletStep$ChunkTransactionCallback.doInTransaction(TaskletStep.java:386)
     at org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:130)
     at org.springframework.batch.core.step.tasklet.TaskletStep$2.doInChunkContext(TaskletStep.java:264)
     at org.springframework.batch.core.scope.context.StepContextRepeatCallback.doInIteration(StepContextRepeatCallback.java:76)
     at org.springframework.batch.repeat.support.RepeatTemplate.getNextResult(RepeatTemplate.java:367)
     at org.springframework.batch.repeat.support.RepeatTemplate.executeInternal(RepeatTemplate.java:214)
     at org.springframework.batch.repeat.support.RepeatTemplate.iterate(RepeatTemplate.java:143)
     at org.springframework.batch.core.step.tasklet.TaskletStep.doExecute(TaskletStep.java:250)
     at org.springframework.batch.core.step.AbstractStep.execute(AbstractStep.java:195)
     at org.springframework.batch.core.job.SimpleStepHandler.handleStep(SimpleStepHandler.java:135)
     at org.springframework.batch.core.job.flow.JobFlowExecutor.executeStep(JobFlowExecutor.java:61)
     at org.springframework.batch.core.job.flow.support.state.StepState.handle(StepState.java:60)
     at org.springframework.batch.core.job.flow.support.SimpleFlow.resume(SimpleFlow.java:144)
     at org.springframework.batch.core.job.flow.support.SimpleFlow.start(SimpleFlow.java:124)
     at org.springframework.batch.core.job.flow.FlowJob.doExecute(FlowJob.java:135)
     at org.springframework.batch.core.job.AbstractJob.execute(AbstractJob.java:281)
     at org.springframework.batch.core.launch.support.SimpleJobLauncher$1.run(SimpleJobLauncher.java:120)
     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
     at java.lang.Thread.run(Thread.java:724)
Caused by: java.lang.IllegalStateException: Already value [org.springframework.jdbc.datasource.ConnectionHolder@43f9e588] for key [org.springframework.jdbc.datasource.DriverManagerDataSource@84f171a] bound to thread [jobLauncherTaskExecutor-1]
     at org.springframework.transaction.support.TransactionSynchronizationManager.bindResource(TransactionSynchronizationManager.java:189)
     at org.springframework.orm.jpa.JpaTransactionManager.doBegin(JpaTransactionManager.java:402)
... 36 more

同一个Job在独立应用程序中执行正常.该问题仅发生在Spring-Batch-Admin环境中.您可以在下面看到项目结构和依赖项:

这是覆盖/扩展Batch-Admin配置的app-context.xml:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:batch="http://www.springframework.org/schema/batch"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:task="http://www.springframework.org/schema/task" xmlns:jdbc="http://www.springframework.org/schema/jdbc"
    xmlns:tx="http://www.springframework.org/schema/tx"
    xsi:schemaLocation="http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
        http://www.springframework.org/schema/batch http://www.springframework.org/schema/batch/spring-batch-2.1.xsd
        http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc-3.0.xsd
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd
        http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task-3.2.xsd">

    <context:component-scan base-package="com.company.batch" />

    <context:property-placeholder location="classpath:batch.properties" />

    <import resource="classpath:/META-INF/spring/batch/jobs/article-job.xml" />

    <bean id="dataSource"
        class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="${batch.jdbc.driver}" />
        <property name="url" value="${batch.jdbc.url}" />
        <property name="username" value="${batch.jdbc.user}" />
        <property name="password" value="${batch.jdbc.password}" />
    </bean>

    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
        <property name="dataSource" ref="dataSource"></property>
    </bean>

    <bean id="entityManagerFactory"
        class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="dataSource" ref="dataSource" />
        <property name="packagesToScan" value="com.qompa.batch" />
        <property name="jpaVendorAdapter">
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
                <property name="database" value="POSTGRESQL"></property>
                <property name="showSql" value="true" />
                <property name="generateDdl" value="false" />
                <property name="databasePlatform" value="com.company.utils.persistence.CustomPGDialect" />
            </bean>
        </property>
        <property name="jpaProperties">
            <props>
                <prop key="hibernate.hbm2ddl.auto"></prop>
            </props>
        </property>
    </bean>

    <bean id="txManager" class="org.springframework.orm.jpa.JpaTransactionManager">
        <property name="entityManagerFactory" ref="entityManagerFactory" />
    </bean>
    <tx:annotation-driven transaction-manager="txManager" />

    <!-- schedule tasks -->
    <task:scheduled-tasks>
        <task:scheduled ref="articleRetrieval" method="run"
            cron="0 0 */4 * * *" />
        <task:scheduled ref="articleConversion" method="run"
            cron="0 15 */4 * * *" />
    </task:scheduled-tasks>
</beans>

到目前为止我所理解的是它与bean引用的ThreadPoolTask​​Executor有关jobLauncherTaskExecutor.它似乎处理并发运行作业的连接池 ...但说实话,我不知道如何更改我的配置,使这些工作.

[编辑]:我甚至不确定它是否是未提及的ThreadPoolTask​​Executor.但它似乎是TaskExecutor接口的实现.

如果有人遇到类似的问题,或者有一个建议如何配置我的应用程序的方式可以为我的持久性方法创建事务:请给我一个提示!

Answer 1

错误来自JpaTransactionManager第403行:

TransactionSynchronizationManager.bindResource(getDataSource(), conHolder);

该错误意味着事务管理器正在尝试将数据源(而不是实体管理器)绑定到线程,但数据源已经存在,这是意外的.

请注意,事务管理器尚未启动将实体管理器绑定到线程,这将在JpaTransactionManager第416行接下来发生:

有两种可能的解释:

• 某人(另一个事务管理器？)是在事务管理器之前将数据源添加到线程,这是意外的.

• 或者没有人将数据源添加到事务管理器,只是在任务执行结束时,没有人在将线程返回到池之前清除线程,可能是由于错误或未处理的异常.

有一个问题,这种情况是否只发生在一个执行线程中,或者只有多个执行线程？

要找出问题所在,这些是一些步骤:

• 以最少数量的线程运行导致问题

• 设置断点TransactionSynchronizationManager.bindResource()以查看谁添加了与线程的连接.断点可以是条件断点,在线程名称上有条件:"jobLauncherTaskExecutor-1".equals(Thread.currentThread().getName())

• 还放入一个断点TransactionSynchronizationManager.unbindResource(),以查看数据源是否从线程中解除绑定.当断点命中时,向下滚动堆栈跟踪并查看导致这种情况的类.

Answer 2

当您有多个事务管理器时,通常会发生这种情况.

一些提示......

当使用注释@EnableBatchProcessing时,Spring Batch会自动注册一个事务管理器,并且您的JpaTransactionManager可能永远不会被使用.如果要更改spring批处理使用的事务管理器,则必须实现BatchConfigurer接口.(https://blog.codecentric.de/en/2013/06/spring-batch-2-2-javaconfig-part- 3-profiles-and-environments /).

您可以为tasklet指定事务管理器,如下所示:

<tasklet transaction-manager="transactionManager">

Answer 3

如果您有 2 个数据源，我建议您阅读：

https://github.com/spring-projects/spring-boot/issues/3012

所以...配置主数据源（事务管理器的名字很重要）

@Configuration
@EnableJpaRepositories(
        entityManagerFactoryRef = "entityManager",
        transactionManagerRef = "transactionManager",
        basePackages = "a.b.c")
@PropertySource({"classpath:db_persistence.properties"})
@EnableTransactionManagement

和另一个数据源：

@Configuration
@EnableJpaRepositories(
        entityManagerFactoryRef = "another_EntityManager",
        transactionManagerRef = "another_transactionManager",
        basePackages = "x.y.z")
@PropertySource({"classpath:db_persistence.properties"})
@EnableTransactionManagement

我希望这对你有帮助。