Jpa findBy用法

项目GitHub地址

https://github.com/1913045515/JPA

代码

package com.lzq.jpa.entity.repository;

import com.lzq.jpa.entity.User;

import org.springframework.data.jpa.repository.JpaRepository;

import java.util.List;

/**

* Created by qiang on 2018/1/22.

*/

public interface UserRepository extends JpaRepository{

/**

* 相当于 select *from user where name=?

* @param name

* @return

*/

public List findByName(String name);

/**

* 相当于select *from user where name like ?

* 但是有一点需要注意的是，%需要我们自己来写

* @param name

* @return

*/

public List findByNameLike(String name);

/**

* 相当于select *from user where name not like ?

* 但是有一点需要注意的是，%需要我们自己来写

* @param name

* @return

*/

public List findByNameNotLike(String name);

/**

* 相当于 select *from user where name <> ?

* @param name

* @return

*/

public List findByNameNot(String name);

/**

* 相当于 select *from user where id in (?)

* @param ids

* @return

*/

public List findByIdIn(List ids);

/**

* 相当于 select *from user where id not in ()

* @param ids

* @return

*/

public List findByIdNotIn(List ids);

/**

* 相当于 select *from user where name=? order by height desc

* @param name

* @return

*/

public List findByNameOrderByHeightDesc(String name);

/**

* 相当于 select *from user where name=? order by height asc

* @param name

* @return

*/

public List findByNameOrderByHeightAsc(String name);

/**

* 相当于 select *from user where name is null

* @return

*/

public List findByNameIsNull();

/**

* 相当于 select *from user where name is not null

* @return

*/

public List findByNameIsNotNull();

/**

* 相当于 select *from user where name =? and height=?

* @param name

* @param height

* @return

*/

public List findByNameAndHeight(String name,int height);

/**

* 相当于 select *from user where name =? or height=?

* @param name

* @param height

* @return

*/

public List findByNameOrHeight(String name,int height);

/**

* 相当于 select *from user where height between ? and ?

* 需要注意的是mysql是有包含两个端点值的

* @param start

* @param end

* @return

*/

public List findByHeightBetween(int start,int end);

/**

* 相当于 select *from user where height < ?

* 需要注意的是mysql是没有包含端点值的

* @param less

* @return

*/

public List findByHeightLessThan(int less);

/**

* 相当于 select *from user where height > ?

* 需要注意的是mysql是没有包含端点值的

* @param greater

* @return

*/

public List findByHeightGreaterThan(int greater);

}

具体语法规则和对应的sql都在代码中给出来了，这边需要和大家说的是UserRepository接口的特点。我们通过继承JpaRepository《对应的实体类，主键属性值》来编写findBy等相关的函数来查询数据库。继承JpaRepository的接口在使用的时候，通过@Autowired会自动创建接口的实现类，不需要怎么去实现这个接口，这也是jpa最方便的地方。

5.通过控制类调用dao接口

package com.lzq.jpa.controller;

import com.lzq.jpa.entity.User;

import com.lzq.jpa.entity.repository.UserRepository;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RequestMethod;

import org.springframework.web.bind.annotation.ResponseBody;

import java.util.ArrayList;

import java.util.List;

/**

* Created by qiang on 2018/1/22.

*/

@Controller

@RequestMapping(value = "jpa")

public class UserController {

@Autowired

private UserRepository userRepository;

@RequestMapping(value = "findByName",method = RequestMethod.GET)

@ResponseBody

public List findByName(String name){

return userRepository.findByName(name);

}

@RequestMapping(value = "findByHeightBetween",method = RequestMethod.GET)

@ResponseBody

public List findByHeightBetween(int start,int end){

return userRepository.findByHeightBetween(start,end);

}

@RequestMapping(value = "findByHeightLessThan",method = RequestMethod.GET)

@ResponseBody

public List findByHeightLessThan(int less){

return userRepository.findByHeightLessThan(less);

}

@RequestMapping(value = "findByHeightGreaterThan",method = RequestMethod.GET)

@ResponseBody

public List findByHeightGreaterThan(int greater){

return userRepository.findByHeightGreaterThan(greater);

}

@RequestMapping(value = "findByNameAndHeight",method = RequestMethod.GET)

@ResponseBody

public List findByNameAndHeight(String name,int height){

return userRepository.findByNameAndHeight(name,height);

}

@RequestMapping(value = "findByNameOrHeight",method = RequestMethod.GET)

@ResponseBody

public List findByNameOrHeight(String name,int height){

return userRepository.findByNameOrHeight(name,height);

}

@RequestMapping(value = "findByNameIsNull",method = RequestMethod.GET)

@ResponseBody

public List findByNameIsNull(){

return userRepository.findByNameIsNull();

}

@RequestMapping(value = "findByNameIsNotNull",method = RequestMethod.GET)

@ResponseBody

public List findByNameIsNotNull(){

return userRepository.findByNameIsNotNull();

}

@RequestMapping(value = "findByNameOrderByHeightDesc",method = RequestMethod.GET)

@ResponseBody

public List findByNameOrderByHeightDesc(String name){

return userRepository.findByNameOrderByHeightDesc(name);

}

@RequestMapping(value = "findByNameOrderByHeightAsc",method = RequestMethod.GET)

@ResponseBody

public List findByNameOrderByHeightAsc(String name){

return userRepository.findByNameOrderByHeightAsc(name);

}

@RequestMapping(value = "findByNameLike",method = RequestMethod.GET)

@ResponseBody

public List findByNameLike(String name){

return userRepository.findByNameLike("%"+name+"%");

}

@RequestMapping(value = "findByNameNotLike",method = RequestMethod.GET)

@ResponseBody

public List findByNameNotLike(String name){

return userRepository.findByNameNotLike("%"+name+"%");

}

@RequestMapping(value = "findByNameNot",method = RequestMethod.GET)

@ResponseBody

public List findByNameNot(String name){

return userRepository.findByNameNot(name);

}

@RequestMapping(value = "findByIdIn",method = RequestMethod.GET)

@ResponseBody

public List findByIdIn(String ids){

Listlist=new ArrayList<>();

String[] idsStr=ids.split(",");

for(String id:idsStr){

list.add(id);

}

return userRepository.findByIdIn(list);

}

@RequestMapping(value = "findByIdNotIn",method = RequestMethod.GET)

@ResponseBody

public List findByIdNotIn(String ids){

Listlist=new ArrayList<>();

String[] idsStr=ids.split(",");

for(String id:idsStr){

list.add(id);

}

return userRepository.findByIdNotIn(list);

}

}

转载地址

https://blog.csdn.net/linzhiqiang0316/article/details/79177077