一对多关系

 

新建员工信息

 

package com.rich.springdatajpa.controller;

import com.rich.springdatajpa.entity.Dept;
import com.rich.springdatajpa.entity.Emp;
import com.rich.springdatajpa.repository.DeptRepository;
import com.rich.springdatajpa.repository.EmpRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.Date;
import java.util.List;

@RestController
//@Controller
// 使用@RestController的时候默认所有方法都返回JSON字符串，
/// 而不是跳转页面，我们也不用在方法上写@ResponseBody
@RequestMapping("/emp")
//默认该类的所有方法都开启事务
@Transactional(rollbackFor = Exception.class)
public class EmpController {
    @Autowired
    private EmpRepository empRepository;
    @Autowired
    private DeptRepository deptRepository;

    @GetMapping("/{id}")
    public Emp findById(@PathVariable("id") Integer id){
        return empRepository.findById(id).get();
    }

    @GetMapping("/create")
    public Emp create(){
        Emp emp = new Emp();
        emp.setComm(0f);
        emp.setEname("laoqi");
        emp.setHiredate(new Date());
        emp.setJob("Teacher");
        emp.setMgr(null);
        emp.setSal(0f);

        Dept d = deptRepository.findById(20).get();
        emp.setDept(d);

        empRepository.save(emp);
        return emp;
    }

需求 根据部门编号查询所有员工的信息

Repository 文件实现

 

 

public interface EmpRepository extends JpaRepository<Emp,Integer> {

    //select * from emp where deptno = ?
    @Query("select e from Emp e where e.dept.deptno=:dn")
    public List<Emp> findEmps(@Param("dn") Integer deptno);

}

controller文件实现

    @GetMapping("/find")
    public List<Emp> find(Integer deptno){
        return empRepository.findEmps(deptno);
    }

 验证代码

在浏览器中输入 http://localhost:8089/emp/find?deptno=20