org.hibernate.exception.GenericJDBCException: 无法执行结果的顺序读取（向前）

huangapple
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英文:

org.hibernate.exception.GenericJDBCException: could not perform sequential read of results (forward)

问题

以下是翻译好的部分：

我正在使用 Hibernate 版本 - 5.4.12.Final 和 mysql-connector-java 驱动版本 - 8.0.18。 <br>
我的实体：<br>

  1. @Entity
  2. public class Author {
  3.     
  4.     @Id
  5.     private long id;
  6.     
  7.     @OneToMany(mappedBy = "author", fetch = FetchType.LAZY)
  8.     private Set<Post> posts = new HashSet<>();
  9.     
  10.     // 获取器和设置器...
  11. }
  13. @Entity
  14. public class Post {
  15.     
  16.     @Id
  17.     private long id;
  18.     
  19.     @ManyToOne(cascade = {CascadeType.MERGE, CascadeType.PERSIST}, fetch = FetchType.LAZY)
  20.     @JoinColumn(name = "author_id")
  21.     private Author author;
  22.     
  23.     @OneToMany(mappedBy = "post", fetch = FetchType.LAZY, cascade = {CascadeType.REMOVE, CascadeType.REFRESH, CascadeType.DETACH}, orphanRemoval = true)
  24.     private List<PostComment> postComments = new ArrayList<>();
  25.     
  26.     // 获取器和设置器...
  27. }
  29. @Entity
  30. public class PostComment {
  31.     
  32.     @Id
  33.     private long id;
  34.     
  35.     @ManyToOne(fetch = FetchType.LAZY)
  36.     @JoinColumn(name = "post_id")
  37.     private Post post;
  38.     
  39.     // 获取器和设置器...
  40. }

当我运行这个 JPQL 查询时：<br>

  1. SELECT post FROM Post post 
  2.     LEFT JOIN FETCH post.author author 
  3.     LEFT JOIN FETCH post.postComments postComments 
  4. WHERE author.id = :authorId

然后出现了这个错误：

  1. org.hibernate.exception.GenericJDBCException: could not perform sequential read of results (forward)
  2.     ...

但是当我运行以下查询时，就没有错误：

  1. SELECT post FROM Post post 
  2.     LEFT JOIN FETCH post.author author 
  3.     LEFT JOIN post.postComments postComments 
  4. WHERE author.id = :authorId

问题：<br>
为什么我不能使用 FETCH JOIN？<br>
为什么会出现这个错误？<br>
如何修复这个问题？<br>

英文:

I am using Hibernate version - 5.4.12.Final and mysql-connector-java driver version - 8.0.18. <br>
My entities:<br>

  1. @Entity
  2. public class Author {
  3. 	
  4. 	@Id
  5. 	private long id;
  6. 	
  7. 	@OneToMany(mappedBy = &quot;author&quot;, fetch = FetchType.LAZY)
  8.     private Set&lt;Post&gt; posts = new HashSet&lt;&gt;();
  9. 	
  10. 	//Getters and setters...
  11. }
  13. @Entity
  14. public class Post {
  15. 	
  16. 	@Id
  17. 	private long id;
  18. 	
  19.     @ManyToOne(cascade = {CascadeType.MERGE, CascadeType.PERSIST}, fetch = FetchType.LAZY)
  20.     @JoinColumn(name = &quot;author_id&quot;)
  21.     private Author author;
  22. 	
  23. 	@OneToMany(mappedBy = &quot;post&quot;, fetch = FetchType.LAZY, cascade = {CascadeType.REMOVE, CascadeType.REFRESH, CascadeType.DETACH}, orphanRemoval = true)
  24.     private List&lt;PostComment&gt; postComments = new ArrayList&lt;&gt;();
  25. 	
  26. 	
  27. 	//Getters and setters...
  28. 	
  29. }
  31. @Entity
  32. public class PostComment {
  33. 	
  34. 	@Id
  35. 	private long id;
  36. 	
  37. 	@ManyToOne(fetch = FetchType.LAZY)
  38.     @JoinColumn(name = &quot;post_id&quot;)
  39.     private Post post;
  40. 	
  41. 	
  42. 	//Getters and setters...
  43. 	
  44. }

When I run this JPQL query:<br>

  1. SELECT post FROM Post post 
  2. 	LEFT JOIN FETCH post.author author 
  3. 	LEFT JOIN FETCH post.postComments postComments 
  4. WHERE author.id = :authorId

Then this error appears:

  1. org.hibernate.exception.GenericJDBCException: could not perform sequential read of results (forward)
  2. at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:47)
  3. at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:113)
  4. at org.hibernate.loader.Loader.loadSequentialRowsForward(Loader.java:544)
  5. at org.hibernate.internal.FetchingScrollableResultsImpl.next(FetchingScrollableResultsImpl.java:71)
  6. at org.hibernate.query.internal.ScrollableResultsIterator.hasNext(ScrollableResultsIterator.java:33)
  7. at java.base/java.util.Iterator.forEachRemaining(Iterator.java:132)
  8. at java.base/java.util.Spliterators$IteratorSpliterator.forEachRemaining(Spliterators.java:1801)
  9. at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:484)
  10. at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474)
  11. at java.base/java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:913)
  12. at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
  13. at java.base/java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:578)
  14. at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218)
  15. at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:771)
  16. at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163)
  17. at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:749)
  18. at org.springframework.aop.aspectj.MethodInvocationProceedingJoinPoint.proceed(MethodInvocationProceedingJoinPoint.java:88)
  19. at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  20. at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
  21. at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
  22. at java.base/java.lang.reflect.Method.invoke(Method.java:566)
  23. at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethodWithGivenArgs(AbstractAspectJAdvice.java:644)
  24. at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethod(AbstractAspectJAdvice.java:633)
  25. at org.springframework.aop.aspectj.AspectJAroundAdvice.invoke(AspectJAroundAdvice.java:70)
  26. at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
  27. at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:749)
  28. at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:95)
  29. at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
  30. at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:749)
  31. at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:691)	
  32. at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218)
  33. at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:771)
  34. at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163)
  35. at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:749)
  36. at org.springframework.aop.aspectj.AspectJAfterThrowingAdvice.invoke(AspectJAfterThrowingAdvice.java:62)
  37. at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
  38. at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:749)
  39. at org.springframework.aop.aspectj.MethodInvocationProceedingJoinPoint.proceed(MethodInvocationProceedingJoinPoint.java:88)
  40. at no.vergemal.service.aop.ExecutionTimeAspect.logExecutionTime(ExecutionTimeAspect.java:37)
  41. at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  42. at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
  43. at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
  44. at java.base/java.lang.reflect.Method.invoke(Method.java:566)
  45. at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethodWithGivenArgs(AbstractAspectJAdvice.java:644)
  46. at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethod(AbstractAspectJAdvice.java:633)
  47. at org.springframework.aop.aspectj.AspectJAroundAdvice.invoke(AspectJAroundAdvice.java:70)
  48. at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
  49. at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:749)
  50. at org.springframework.aop.framework.adapter.MethodBeforeAdviceInterceptor.invoke(MethodBeforeAdviceInterceptor.java:56)
  51. at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:175)
  52. at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:749)
  53. at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:367)
  54. at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:118)
  55. at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
  56. at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:749)
  57. at org.springframework.aop.aspectj.MethodInvocationProceedingJoinPoint.proceed(MethodInvocationProceedingJoinPoint.java:88)
  58. at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  59. at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
  60. at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
  61. at java.base/java.lang.reflect.Method.invoke(Method.java:566)
  62. at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethodWithGivenArgs(AbstractAspectJAdvice.java:644)
  63. at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethod(AbstractAspectJAdvice.java:633)
  64. at org.springframework.aop.aspectj.AspectJAroundAdvice.invoke(AspectJAroundAdvice.java:70)
  65. at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
  66. at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:749)
  67. at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:95)
  68. at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
  69. at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:749)
  70. at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:691)	
  71. at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  72. at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
  73. at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
  74. at java.base/java.lang.reflect.Method.invoke(Method.java:566)
  75. at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
  76. at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
  77. at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
  78. at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
  79. at org.springframework.test.context.junit4.statements.RunBeforeTestExecutionCallbacks.evaluate(RunBeforeTestExecutionCallbacks.java:74)
  80. at org.springframework.test.context.junit4.statements.RunAfterTestExecutionCallbacks.evaluate(RunAfterTestExecutionCallbacks.java:84)
  81. at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
  82. at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75)
  83. at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)
  84. at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86)
  85. at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84)
  86. at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
  87. at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:251)
  88. at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:97)
  89. at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
  90. at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
  91. at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
  92. at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
  93. at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
  94. at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
  95. at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
  96. at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
  97. at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:190)
  98. at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
  99. Caused by: java.sql.SQLException: Before start of result set
  100. at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:129)
  101. at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97)
  102. at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:89)
  103. at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:63)
  104. at com.mysql.cj.jdbc.result.ResultSetImpl.checkRowPos(ResultSetImpl.java:484)
  105. at com.mysql.cj.jdbc.result.ResultSetImpl.getObject(ResultSetImpl.java:1288)
  106. at com.mysql.cj.jdbc.result.ResultSetImpl.getLong(ResultSetImpl.java:812)
  107. at com.mysql.cj.jdbc.result.ResultSetImpl.getLong(ResultSetImpl.java:818)
  108. at org.apache.commons.dbcp2.DelegatingResultSet.getLong(DelegatingResultSet.java:653)
  109. at org.apache.commons.dbcp2.DelegatingResultSet.getLong(DelegatingResultSet.java:653)
  110. at org.hibernate.type.descriptor.sql.BigIntTypeDescriptor$2.doExtract(BigIntTypeDescriptor.java:63)
  111. at org.hibernate.type.descriptor.sql.BasicExtractor.extract(BasicExtractor.java:47)
  112. at org.hibernate.type.AbstractStandardBasicType.nullSafeGet(AbstractStandardBasicType.java:257)
  113. at org.hibernate.type.AbstractStandardBasicType.nullSafeGet(AbstractStandardBasicType.java:253)
  114. at org.hibernate.type.AbstractStandardBasicType.nullSafeGet(AbstractStandardBasicType.java:243)
  115. at org.hibernate.loader.Loader.getKeyFromResultSet(Loader.java:1512)
  116. at org.hibernate.loader.Loader.loadSequentialRowsForward(Loader.java:533)
  117. ... 112 more

But when I run this query then there is no errors:

  1. SELECT post FROM Post post 
  2. LEFT JOIN FETCH post.author author 
  3. LEFT JOIN post.postComments postComments 
  4. WHERE author.id = :authorId

Questions:<br>
Why am I not able to use FETCH JOIN?<br>
Why does this error appear here?<br>
How can I fix it?<br>

答案1

得分: 0

问题出在流式结果集上。为了修复它，需要将这段代码替换为：

  1. return new HashSet<>(query.getResultList());
英文:

The problem was in streaming result set. In order to fix it need to replace this code:

  1. return query.getResultStream().collect(Collectors.toSet());

with such code:

  1. return new HashSet&lt;&gt;(query.getResultList());

huangapple
  • 本文由 发表于 2020年8月22日 18:33:36
  • 转载请务必保留本文链接：https://go.coder-hub.com/63535148.html
  • hibernate
  • java
  • jpql
  • mysql
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