java - Spring 数据JPA : Find all by example and page and return DTO (Projection)

Question

我正在尝试查找我的实体作为 EntityDTO 的所有数据。我知道如何以 DTO 形式查找所有数据，但我想使用示例对象放置一些过滤器并获取页面作为结果。

我在存储库中创建了一个方法:

Page<T> findBy(Example e, Pageable p, Class<T> type);

但是调用此方法会导致错误

IllegalArgumentException: At least 1 parameter(s) provided but only 0 parameter(s) present in query.

这是完整的堆栈跟踪:

org.springframework.dao.InvalidDataAccessApiUsageException: At least 1 parameter(s) provided but only 0 parameter(s) present in query.; nested exception is java.lang.IllegalArgumentException: At least 1 parameter(s) provided but only 0 parameter(s) present in query.
org.springframework.orm.jpa.EntityManagerFactoryUtils.convertJpaAccessExceptionIfPossible(EntityManagerFactoryUtils.java:374)
org.springframework.orm.jpa.vendor.HibernateJpaDialect.translateExceptionIfPossible(HibernateJpaDialect.java:257)
org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.translateExceptionIfPossible(AbstractEntityManagerFactoryBean.java:528)
org.springframework.dao.support.ChainedPersistenceExceptionTranslator.translateExceptionIfPossible(ChainedPersistenceExceptionTranslator.java:61)
org.springframework.dao.support.DataAccessUtils.translateIfNecessary(DataAccessUtils.java:242)
org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:153)
org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodInterceptor.invoke(CrudMethodMetadataPostProcessor.java:149)\r\n\tat org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:95)
org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:212)
com.sun.proxy.$Proxy132.findBy(Unknown Source)

Answer 1

在 Spring 存储库接口(interface)中，查询是根据方法名称创建的。

请尝试这个:

Page<T> findByExample(Example e, Pageable p, Class<T> type);

如果不起作用，您可以在这里找到解决方案:

https://docs.spring.io/spring-data/jpa/docs/current/reference/html/#repositories