在JPA的@Query注解中使用limit条件(详解)

所属分类：软件编程 / java 阅读数： 26

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在@Query注解注释的JPQL语句中写limit语句是会报错的

unexpected token :limit near line ....

解决方法是讲@Query注解中的limit语句去掉，然后传一个Pageable pageable=new PageRequest(offset,limit)进去

示例代码：

controller

import java.util.List; 
 
import org.springframework.beans.factory.annotation.Autowired; 
import org.springframework.web.bind.annotation.RequestMapping; 
import org.springframework.web.bind.annotation.RestController; 
 
@RestController 
@RequestMapping(value = "/misaka") 
public class MisakaController 
{ 
  @Autowired 
  private MisakaService misakaService; 
 
  @RequestMapping(value = "/list") 
  public List<Misaka> getBaselineOverview() 
  { 
    return misakaService.getMisaka(); 
  } 
 
}

service

import java.util.List; 
 
public interface MisakaService 
{ 
  List<Misaka> getMisaka(); 
}

serviceimpl

import java.util.List; 
 
import org.springframework.beans.factory.annotation.Autowired; 
import org.springframework.data.domain.Page; 
import org.springframework.data.domain.PageRequest; 
import org.springframework.data.domain.Pageable; 
import org.springframework.data.domain.Sort.Direction; 
import org.springframework.stereotype.Service; 
 
@Service 
public class MisakaServiceImpl implements MisakaService 
{ 
  @Autowired 
  private MisakaDao misakaDao; 
 
  @Override 
  public List<Misaka> getMisaka() 
  { 
    Pageable pageable = new PageRequest(1, 2, Direction.ASC, "name"); 
    Page<Misaka> misakaPage = misakaDao.search(pageable); 
    List<Misaka> misakaList = misakaPage.getContent(); 
    System.out.println(misakaList); 
    return misakaList; 
  } 
}

dao

import org.springframework.data.domain.Page; 
import org.springframework.data.domain.Pageable; 
import org.springframework.data.jpa.repository.Query; 
import org.springframework.data.repository.CrudRepository; 
 
public interface MisakaDao extends CrudRepository<Misaka, Long> 
{ 
  @Query("SELECT m FROM Misaka m WHERE m.id>4") 
  Page<Misaka> search(Pageable pageable); 
}

model

import javax.persistence.Column; 
import javax.persistence.Entity; 
import javax.persistence.GeneratedValue; 
import javax.persistence.GenerationType; 
import javax.persistence.Id; 
import javax.persistence.Table; 
 
@Entity 
@Table(name = "t_test") 
public class Misaka 
{ 
  @Id 
  @GeneratedValue(strategy = GenerationType.AUTO) 
  private Long id; 
 
  @Column(name = "name") 
  private String name; 
 
  public Long getId() 
  { 
    return id; 
  } 
 
  public void setId(Long id) 
  { 
    this.id = id; 
  } 
 
  public String getName() 
  { 
    return name; 
  } 
 
  public void setName(String name) 
  { 
    this.name = name; 
  } 
 
  @Override 
  public String toString() 
  { 
    return "Misaka [id=" + id + ", name=" + name + "]"; 
  } 
 
}

数据库t_test

id	name
1	m1
2	m2
3	m3
4	m4
5	m5
6	m6
7	m7
8	m8
9	m9

输出

Hibernate: select count(misaka0_.id) as col_0_0_ from t_test misaka0_ where misaka0_.id>4 
Hibernate: select misaka0_.id as id1_29_, misaka0_.name as name2_29_ from t_test misaka0_ where misaka0_.id>4 order by misaka0_.name asc limit ?, ? 
[Misaka [id=7, name=m7], Misaka [id=8, name=m8]]

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