无分页计数的Spring数据存储库QueryDslPredicateExecutor

Question

我试图创建一个spring数据存储库，它使用一个方法列出一页实体和一个QueryDSL谓词，使用以下内容：

public interface EntityRespository extends JpaRepository<Entity, Integer>, QueryDslPredicateExecutor<Entity> {

    List<Entity> findAllBy(Predicate predicate, Pageable pageable);

}

正如这里提到的禁用从PageRequest获取总页数的计数查询的方法，我尝试使用“技巧”用“FindAllby”命名方法。

java.util.NoSuchElementException
    at java.util.ArrayList$Itr.next(ArrayList.java:834)
    at java.util.Collections$UnmodifiableCollection$1.next(Collections.java:1067)
    at org.springframework.data.jpa.repository.query.CriteriaQueryParameterBinder.bind(CriteriaQueryParameterBinder.java:63)
    at org.springframework.data.jpa.repository.query.ParameterBinder.bind(ParameterBinder.java:111)
    at org.springframework.data.jpa.repository.query.ParameterBinder.bindAndPrepare(ParameterBinder.java:172)
    at org.springframework.data.jpa.repository.query.ParameterBinder.bindAndPrepare(ParameterBinder.java:163)
    at org.springframework.data.jpa.repository.query.PartTreeJpaQuery$QueryPreparer.invokeBinding(PartTreeJpaQuery.java:207)
    at org.springframework.data.jpa.repository.query.PartTreeJpaQuery$QueryPreparer.createQuery(PartTreeJpaQuery.java:134)
    at org.springframework.data.jpa.repository.query.PartTreeJpaQuery.doCreateQuery(PartTreeJpaQuery.java:74)
    at org.springframework.data.jpa.repository.query.AbstractJpaQuery.createQuery(AbstractJpaQuery.java:169)
    at org.springframework.data.jpa.repository.query.JpaQueryExecution$CollectionExecution.doExecute(JpaQueryExecution.java:113)
    at org.springframework.data.jpa.repository.query.JpaQueryExecution.execute(JpaQueryExecution.java:77)
    at org.springframework.data.jpa.repository.query.AbstractJpaQuery.doExecute(AbstractJpaQuery.java:100)
    at org.springframework.data.jpa.repository.query.AbstractJpaQuery.execute(AbstractJpaQuery.java:91)
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.doInvoke(RepositoryFactorySupport.java:393)
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:371)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:99)
    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:281)
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:136)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodIntercceptor.invoke(CrudMethodMetadataPostProcessor.java:122)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:207)
    at com.sun.proxy.$Proxy86.findAllBy(Unknown Source)

List<Entity> findAllBy(Pageable pageable);

如何在不发出count查询的情况下使用Pageable创建QueryDSL存储库？在最后一页之后执行额外的查询以获取下一页，而不是对每个页面请求发出额外的计数查询，这样做更便宜。

Answer 1

这基本上是对查询派生机制的无效使用。执行谓词实例和查询方法是一种不同的机制，不能混合在一起。您基本上声明一个查询方法，它不接受任何参数（没有任何标准）位，然后接受一个谓词，该谓词

不幸的是，在存储库基接口和QueryDSLPredicateExecutor中声明的方法只能重新声明以返回更具体的类型（例如，重写FindAll()以返回List 而不是Iterable ，因为实现实际上返回的是实现更具体类型的类型）。

我建议像这里描述的那样创建一个自定义实现。