eclipse中搭建springboot学习（9）---JPA使用3（多张表 OneToOne）

StudentDTO

package com.example.demo1025.dto;

import java.io.Serializable;

import javax.persistence.CascadeType; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.Id; import javax.persistence.OneToOne; import javax.persistence.Table;

@Entity @Table(name = "student") public class StudentDTO implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id     @GeneratedValue     @Column(name = "student_id")     private int id;

    private String studentName;

    @OneToOne(cascade = CascadeType.ALL)     // 设置cascade，否则会报错object references an unsaved transient instance - save the     // transient instance before flushing :     // com.example.demo1025.dto.StudentDTO.score ->     // com.example.demo1025.dto.ScoreDTO     private ScoreDTO score;

    public int getId() {         return id;     }

    public void setId(int id) {         this.id = id;     }

    public String getStudentName() {         return studentName;     }

    public void setStudentName(String studentName) {         this.studentName = studentName;     }

    public ScoreDTO getScoreDTO() {         return score;     }

    public void setScoreDTO(ScoreDTO scoreDTO) {         this.score = scoreDTO;     }

}

ScoreDTO

package com.example.demo1025.dto;

import java.io.Serializable;

import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.Id; import javax.persistence.OneToOne; import javax.persistence.Table;

@Entity @Table(name = "score") public class ScoreDTO implements Serializable {

    /**      *       */     private static final long serialVersionUID = 1L;

    @Id     @GeneratedValue     private int id;

    private String eng_score;     private String math_score;

 // mappedBy填写的名称是在StudentDTO类中的名字，而不是表的名称,需要在非主体的那个类中标注出它在主体中的名字     @OneToOne(mappedBy = "score")     private StudentDTO studentDTO;

    public int getId() {         return id;     }

    public void setId(int id) {         this.id = id;     }

    public String getEng_score() {         return eng_score;     }

    public void setEng_score(String eng_score) {         this.eng_score = eng_score;     }

    public String getMath_score() {         return math_score;     }

    public void setMath_score(String math_score) {         this.math_score = math_score;     }

}

StudentScoreRepository

package com.example.demo1025.dao;

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

import com.example.demo1025.dto.StudentDTO;

public interface StudentScoreRepository extends JpaRepository<StudentDTO, Integer> {

}

StudentScoreService 

package com.example.demo1025.service;

import java.util.List;

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

import com.example.demo1025.dao.StudentScoreRepository; import com.example.demo1025.dto.ScoreDTO; import com.example.demo1025.dto.StudentDTO;

@Service public class StudentScoreService {     @Autowired     private StudentScoreRepository studentScoreRepository;

    public void addStudentScore() {         ScoreDTO scoreDTO = new ScoreDTO();         scoreDTO.setEng_score("100");         scoreDTO.setMath_score("84");         StudentDTO studentDTO = new StudentDTO();         studentDTO.setStudentName("小明");         studentDTO.setScoreDTO(scoreDTO);         studentScoreRepository.save(studentDTO);     }

    public List<StudentDTO> getAllStudentScore() {         return studentScoreRepository.findAll();     } }

StuentScoreController  

package com.example.demo1025.controller;

import java.util.List;

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.ResponseBody;

import com.example.demo1025.dto.StudentDTO; import com.example.demo1025.service.StudentScoreService;

@Controller public class StuentScoreController {     @Autowired     private StudentScoreService studentScoreService;

    @RequestMapping("addStudentScore")     @ResponseBody     public String addStudentScore() {         studentScoreService.addStudentScore();         return "添加成功";     }

    @RequestMapping("getAllStudentScore")     @ResponseBody     public List<StudentDTO> getAllStudentScore() {         return studentScoreService.getAllStudentScore();     }

}