Spring Data JPA: Find all by example and page and return DTO (Projection)

Question

I am trying to find all data for my entity as EntityDTO. I know how to find all data as DTO but I want to place some filters using Example object and fetch Page as result.

I created a method in repository as:

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

But invoking this method is resulting in error

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

Here is full stacktrace:

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

In Spring repository interface, the query is created from the method name.

Please try this:

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

If it doesn't work you might find the solution here:

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