运行在TransactionTemplate.execute外部创建的JPA查询时出现TransactionRequiredException

如何解决运行在TransactionTemplate.execute外部创建的JPA查询时出现TransactionRequiredException

我想创建一个jpa查询列表，并在事务内一个接一个地执行它们。

我可以（使用entityManager.createNativeQuery(...)创建查询，并以List<Query>结尾。我想遍历此列表，然后使用TransactionTemplate逐个执行每个查询。

但是我得到一个例外：javax.persistence.TransactionRequiredException: Executing an update/delete query（完整堆栈跟踪位于该问题的底部。）

当我更改代码以便在entityManager.createNativeQuery(...)的内部执行TransactionTemplate.execute时，它工作正常。

问题：

1. 为什么会发生这种异常？
2. 是否可以在TransactionTemplate.execute外部创建jpa查询并在内部执行它？

---

执行创建的查询的服务

package com.myproject;

import com.myproject.DatabaseEntity;
import org.springframework.stereotype.Service;
import org.springframework.beans.factory.annotation.Autowired;

@Service
public class UpdateService {

  private final TransactionTemplate transactionTemplate;

  @Autowired
  public UpdateService(
      final PlatformTransactionManager transactionManager,final BatchedSqlService batchedSqlService) {
    this.transactionManager = transactionManager;
    this.batchedSqlService = batchedSqlService;

    transactionTemplate = new TransactionTemplate(transactionManager);
  }

  public <T extends DatabaseEntity> void update(Class<T> cls,List<T> entities) {
    List<Query> queries = batchedSqlService

    batchedSqlService.convertSqlStringToNativeQuery(entities);

    List<SimpleEntry<String,List<List<String>>>> sqlStringAndParameters = batchedSqlService.getSqlStringAndParameters(cls,entities);
    for (SimpleEntry<String,List<List<String>> sqlStringAndParameter : sqlStringAndParameters) {
      transactionTemplate.<Integer>execute(status -> {
        // jpa Query created INSIDE transaction - WORKS
        Query query = batchedSqlService.convertSqlStringToNativeQuery(sqlStringAndParameter.getKey(),sqlStringAndParameter.getValue());
        return query.executeUpdate();
      });
    }

    List<Query> queries = batchedSqlService.createQueries(cls,entities);
    for (Query q : queries) {
      // jpa Query created OUTSIDE transaction - ERROR -> javax.persistence.TransactionRequiredException: Executing an update/delete query
      transactionTemplate.<Integer>execute(status -> {
        return query.executeUpdate();
      });
    }
  }

  private long runSql(SimpleEntry<String,List<List<String>>> sqlStringAndParameter) {
    return transactionTemplate.<Integer>execute(status -> {
      Query query = dpdEntityBatchedSqlService
          .convertSqlStringToNativeQuery(sqlStringAndParameter.getKey(),sqlStringAndParameter.getValue());
      return query.executeUpdate();
    });
  }
}

创建SQL语句的服务

package com.myproject;

import org.springframework.stereotype.Service;
import javax.persistence.PersistenceContext;
import com.myproject.DatabaseEntity;
import javax.persistence.Query;

@Service
public class BatchedSqlService {

  @PersistenceContext
  private EntityManager entityManager;

  public <T extends DatabaseEntity> List<Query> createQueries(
      Class<T> cls,Collection<T> entities) {

    // converts an entity into a sql string
    List<SimpleEntry<String,List<List<String>>>> listQueriesWithParameters = getSqlStringAndParameters(cls,entities);

    return listQueriesWithParameters.stream()
        .map(it -> convertSqlStringToNativeQuery(it.getKey(),it.getValue()))
        .collect(Collectors.toList());
  }

  public <T extends DatabaseEntity> List<SimpleEntry<String,List<List<String>>>> getSqlStringAndParameters(Class<T> cls,Collection<T> entities) {
    // returns a list of sql strings (e.g. "INSERT into Person name,telephone VALUES (?1,?2) (?3,?4),(?5,6)...") paired with the parameter values,e.g. "Julia" "123456789","Fred" "987654321","Alex 45645342135",...
  }

  /** Convert sql string and list of parameters to jpa Query */
  public Query convertSqlStringToNativeQuery(String sqlString,List<List<String>> batchParameters) {
    Query query = entityManager.createNativeQuery(sqlString);
    List<String> parameters = batchParameters.stream()
        .flatMap(List::stream)
        .collect(Collectors.toList());
    for (int i = 0; i < parameters.size(); i++) {
      query.setParameter(i + 1,parameters.get(i));
    }
    return query;
  }
}

Stacktrace

javax.persistence.TransactionRequiredException: Executing an update/delete query

    at org.hibernate.query.internal.AbstractProducedQuery.executeUpdate(AbstractProducedQuery.java:1492)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.springframework.orm.jpa.SharedEntityManagerCreator$DeferredQueryInvocationHandler.invoke(SharedEntityManagerCreator.java:372)
    at com.sun.proxy.$Proxy119.executeUpdate(Unknown Source)
    at ...UpdateService.lambda$executeQueries$4(UpdateService.java:220)
    at org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:133)
    at ...UpdateService.executeQueries(UpdateService.java:214)
    at ...UpdateService.commitReferenceData(UpdateService.java:147)
    ....
    ....
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
    at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75)
    at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86)
    at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:252)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:94)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
    at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:191)
    at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
    at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
    at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)
    at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:230)
    at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:58)