mysql - 数据库正在覆盖。来自 json 的最后一个条目写入数据库，所有其他条目都被覆盖。仅显示 Json 文件的最后一个条目

Question

PlayerService

这是我的启动应用程序的服务类。

包io.anuj.springbootquickstart.topic;

import java.util.ArrayList;
import java.util.List;

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

@Service
public class PlayerService {

    @Autowired
    private PlayerRespository playerRespository;
    //  private List<Topic> topics = new ArrayList<> (Arrays.asList(
    //          new Topic("Spring","Spring Framework","SpringFramework Description"),
    //          new Topic("Core","Core Framework","CoreFramework Description"),
    //          new Topic("JavaScript","JavaScript Framework","JavaScript Description")));
    public List<Player> getAllPlayer(){
        List<Player> player = new ArrayList();
        playerRespository.findAll()
        .forEach(player::add); //lambda expressions
        return player;
    }
    public Player getPlayer(Long id){
        //return topics.stream().filter(t -> t.getId().equals(id).findFirst().get());
        return playerRespository.findOne(id);
    }
    public void addPlayer(Player player) {

        playerRespository.save(player);

    }
    public void updatePlayer(Long id, Player player) {
        playerRespository.save(player);

    }
    public void deletePlayer(Long id) {
        //topics.removeIf(t -> t.getId().equals(id));
        playerRespository.delete(id);
    }

}



PLayerRepository

这是我的应用程序的播放器存储库。 包 io.anuj.springbootquickstart.topic;

import org.springframework.data.repository.CrudRepository;

public interface PlayerRespository extends CrudRepository <Player, Long>{




    //crud repository-logic of any entity class
    //getallTopic()
    //gettopic(string id)
    //update topic(topic t)
    //deletetopic(string id)


}



PLayerController

这是播放器 Controller

package io.anuj.springbootquickstart.topic;


import java.io.FileReader;
import java.util.List;

import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;


@RestController
//wherever rest controller is written it will give json as output send back as a HTTP response
public class PlayerController {

    @Autowired
    private PlayerService playerService;
    //get request by default
        @RequestMapping("/player")
        public List<Player> getallPlayer(){
            return playerService.getAllPlayer();
            }

    //get request
    @RequestMapping("/player/{id}")
    public Player getPlayer(@PathVariable Long id){
        return  playerService.getPlayer(id);
    }
    //
    @RequestMapping(method=RequestMethod.GET, value= "/getplayer")
    public void addAllPlayer(){

        Player player = new Player();
        JSONParser parser = new JSONParser();

        try {
            Object ob = parser.parse(new FileReader("/home/bridgeit/Desktop/P.D-anuj/Json/newPlayerInfo.json"));
            JSONObject object = (JSONObject) ob;

            JSONArray data = (JSONArray) object.get("Playersinfo");

            for (int i = 0; i < data.size(); i++) 
            {
                JSONObject itemObj = (JSONObject) data.get(i);


                Object nameObj = itemObj.get("player_name");
                String playerName = (String) nameObj;
                player.setPlayer_name(playerName);

                Object imgObject = itemObj.get("player_img_url");
                String playerPic = (String) imgObject;
                player.setPlayer_img_url(playerPic);

                Object roleObj = itemObj.get("player_role");
                String roleName = (String) roleObj;
                player.setPlayer_role(roleName);

                Object battingStyleObj = itemObj.get("player_batting_style");
                String battingStyleName = (String) battingStyleObj;
                player.setPlayer_batting_style(battingStyleName);

                Object bowlingObj = itemObj.get("player_bowling_style");
                String bowlingName = (String) bowlingObj;
                player.setPlayer_bowling_style(bowlingName);

                Object nationalityObj = itemObj.get("player_nationality");
                String nationalityName = (String) nationalityObj;
                player.setPlayer_nationality(nationalityName);

                Object dobObj = itemObj.get("player_dob");
                String dobName = (String) dobObj;
                player.setPlayer_dob(dobName);

                Object teamIdObj = itemObj.get("team_id");
                String teamIdName = (String) teamIdObj;
                player.setTeam_id(teamIdName);


                playerService.addPlayer(player);
            }


        } catch (Exception e) {
            System.out.println(e);
        }

    }
    /*@RequestMapping(method=RequestMethod.PUT, value= "/player/{id}")
    public void updatePlayer(@RequestBody Player player,@PathVariable String id){
        playerService.updatePlayer(id,player);
    }
    @RequestMapping(method=RequestMethod.DELETE, value= "/player/{id}")
    public void deletePlayer(@PathVariable String id){
        playerService.deletePlayer(id);
    }*/
}

this is POJO class
Player.java
package io.anuj.springbootquickstart.topic;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import org.hibernate.annotations.GenericGenerator;

@Entity
/*@Table(name = "Player")*/
public class Player {
    /*@Id
    @GenericGenerator(name = "gene", strategy = "increment")
    @GeneratedValue(generator = "gene")
    @Column(name = "id")
    private Long id;*/

@Id
@GenericGenerator(name = "gene", strategy = "increment")
@GeneratedValue(generator = "gene")
    private long id;
    private String team_id;
    /*@Column(name = "name")*/
    private String player_name;
    /*@Column(name = "display_picture")*/
    private String player_img_url;
    /*@Column(name = "role")*/
    private String player_role;
public Player(long id, String team_id, String player_name, String player_img_url, String player_role,
            String player_batting_style, String player_bowling_style, String player_nationality, String player_dob) {
        super();
        this.id = id;
        this.team_id = team_id;
        this.player_name = player_name;
        this.player_img_url = player_img_url;
        this.player_role = player_role;
        this.player_batting_style = player_batting_style;
        this.player_bowling_style = player_bowling_style;
        this.player_nationality = player_nationality;
        this.player_dob = player_dob;
    }


    /*  @Column(name = "batting_style")*/
    private String player_batting_style;
    /*@Column(name = "bowling_style")*/
    private String player_bowling_style;
    /*@Column(name = "nationality")*/
    private String player_nationality;
    /*@Column(name = "dob")*/
    private String player_dob;
    /*@Column(name = "teamId")*/


    public Player(){
    }











    public String getTeam_id() {
        return team_id;
    }




    public long getId() {
        return id;
    }











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











    public void setTeam_id(String team_id) {
        this.team_id = team_id;
    }


    public String getPlayer_name() {
        return player_name;
    }


    public void setPlayer_name(String player_name) {
        this.player_name = player_name;
    }


    public String getPlayer_img_url() {
        return player_img_url;
    }


    public void setPlayer_img_url(String player_img_url) {
        this.player_img_url = player_img_url;
    }


    public String getPlayer_role() {
        return player_role;
    }


    public void setPlayer_role(String player_role) {
        this.player_role = player_role;
    }


    public String getPlayer_batting_style() {
        return player_batting_style;
    }


    public void setPlayer_batting_style(String player_batting_style) {
        this.player_batting_style = player_batting_style;
    }


    public String getPlayer_bowling_style() {
        return player_bowling_style;
    }


    public void setPlayer_bowling_style(String player_bowling_style) {
        this.player_bowling_style = player_bowling_style;
    }


    public String getPlayer_nationality() {
        return player_nationality;
    }


    public void setPlayer_nationality(String player_nationality) {
        this.player_nationality = player_nationality;
    }


    public String getPlayer_dob() {
        return player_dob;
    }


    public void setPlayer_dob(String player_dob) {
        this.player_dob = player_dob;
    }

    /*public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }*/








    /*public Player(Long id, String team_id, String player_name, String player_img_url, String player_role,
            String player_batting_style, String player_bowling_style, String player_nationality, String player_dob) {
        super();
        this.id = id;
        this.team_id = team_id;
        this.player_name = player_name;
        this.player_img_url = player_img_url;
        this.player_role = player_role;
        this.player_batting_style = player_batting_style;
        this.player_bowling_style = player_bowling_style;
        this.player_nationality = player_nationality;
        this.player_dob = player_dob;
    }
*/
}

当我从 json 文件执行时，它只显示 json 文件的最后一个条目。 JSON 文件包含大约 150 个玩家，但在数据库中只显示玩家的最后一个条目。我认为所有数据都被覆盖了。数据库中只显示该 json 文件的最后一个条目。那是最后一个球员。数据库中只有 json 中最后一个玩家。

Answer 1

这有点难说，因为你有很多注释掉的代码，这让事情更难理解，但我认为这是因为你在 Controller 中创建 Player 的位置。既然你这样做了:

Player player = new Player()

在循环之外，Java 是通过引用值传递的，在您第一次addPlayer 之后，每次都只是用新数据更新同一个播放器。如果您只是调试代码并查看 player 在第一次保存调用后是否有 ID，则可以确认这一点。

您可能想这样做来修复它:

for (int i = 0; i < data.size(); i++) {
    Player player = new Player();
    // rest of your code here
}