Spring JPA存储库中带有分页的自定义查询

Question

我尝试过用Spring Boot实现JPA存储库，它工作得很好。现在，如果我尝试在使用@query注释扩展JpaRepository的接口中实现自定义查询，它可以很好地返回bean列表（使用NamedQuery）。现在，当我尝试为自定义方法/查询使用分页时，它不起作用。

代码：

控制器：

@RequestMapping("/custompages/{pageNumber}")
public String getAllEmployeesUsingNamedQueryWithPaging(@PathVariable Integer pageNumber,Model model)
{
    Page<Employee> page = employeeService.getAllEmployeesUsingNamedQueryWithPaging(pageNumber);

    System.out.println("current page "+page);
    System.out.println("current page content"+page.getContent());

     int current = page.getNumber() + 1;
    int begin = Math.max(1, current - 5);
    int end = Math.min(begin + 10, page.getTotalPages());

    model.addAttribute("empList", page.getContent());
    model.addAttribute("empPages", page);
    model.addAttribute("beginIndex", begin);
    model.addAttribute("endIndex", end);
    model.addAttribute("currentIndex", current);

    return "employeeWorkbench";
}

服务

@Override
public Page<Employee> getAllEmployeesUsingNamedQueryWithPaging(Integer  
pageNumber) {

    PageRequest pageRequest =
            new PageRequest(pageNumber - 1, PAGE_SIZE, 
    Sort.Direction.ASC, "id");
    return   
employeeDao.getAllEmployeesUsingNamedQueryWithPaging(pageRequest);
}

@Transactional
public interface EmployeeDao  extends JpaRepository<Employee, Long>{

@Query(name="HQL_GET_ALL_EMPLOYEE_BY_ID")//Works Fine
public List<Employee> getEmpByIdUsingNamedQuery(@Param("empId") Long
empId);     

@Query(name="HQL_GET_ALL_EMPLOYEE") //throws exception
public Page<Employee> getAllEmployeesUsingNamedQueryWithPaging(Pageable     
pageable);  
}

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 
3.0//EN"  
"http://hibernate.org/dtd/hibernate-mapping-3.0.dtd">

<hibernate-mapping>

<query name="HQL_GET_ALL_EMPLOYEE">from Employee</query>

<query name="HQL_GET_ALL_EMPLOYEE_BY_ID">from Employee where id = 
:empId</query>

</hibernate-mapping>

异常：java.lang.IllegalArgumentException：为TypedQuery[java.lang.Long]指定的类型与查询返回类型[class com.mobicule.springbootjpademo.beans.employee]不兼容

我只想拥有Spring JPA存储库为自定义方法和查询提供的分页功能。我怎样才能做到这一点呢？

Answer 1

我不知道为什么，但由于某种原因，只需执行from entity就会返回“id”，而需要提供在select中返回的实体，如select f from Foo f

public interface FooRepo extends PagingAndSortingRepository<Foo, Long> {

@Query( "select f from Foo f" )
Page<Foo> findAllCustom( Pageable pageable );

Page<Foo> findAllByBarBazContaining( String baz, Pageable pageable );
}

我收到了同样的错误，只有from foo。我还相信，您可以按照名称将这些文件引用到xml文件中。这是我的全部代码

进一步的测试表明Foo f中的也可以工作，我不知道为什么需要别名，也许它是JPQL规范的一部分。

下面是一个测试，显示如何进行简单的分页、按一个属性排序和按多个属性排序

@Test
public void testFindAllCustom() throws Exception {
    Page<Foo> allCustom = fooRepo.findAllCustom( pageable );

    assertThat( allCustom.getSize(), is( 2 ) );

    Page<Foo> sortByBazAsc = fooRepo.findAllCustom( new PageRequest( 0, 2, Sort.Direction.ASC, "bar.baz" ) );

    assertThat( sortByBazAsc.iterator().next().getBar().getBaz(), is( "2baz2bfoo" ) );

    Page<Foo> complexSort = fooRepo.findAllCustom( new PageRequest( 0, 2, new Sort(
            new Sort.Order( Sort.Direction.DESC, "bar.baz" ),
            new Sort.Order( Sort.Direction.ASC, "id" )
    ) ) );

    assertThat( complexSort.iterator().next().getBar().getBaz(), is( "baz1" ) );
}