JPA 问题，尝试保存到数据库时 ID 未注册

Question

我开始进行 Web 开发，但在使用 jpa 时遇到问题。我的 postegre 数据库在手动将数据输入 pgAdmin 时会自动生成一个 id。但是，例如，当尝试通过curl发布帖子时，会出现错误，提示id不能为空，也就是说，id不再自动生成，或者如果是，则在此之前进行验证。我这么说是因为显然其他数据对于注册来说是正确的，并且我知道我的数据库正在工作，因为当我请求获取数据时，数据会出现在客户端上。我正在使用 SpringBoot 和 maven

package com.example.umbrellacorporation.model;
import javax.persistence.*;


@Entity
@Table(name="BOWS")
public class Bows {

  

    

    @Column(name="NAME")
    private String name;

    @Column(name="AUTHOR")
    private String author;

    @Column(name="BIO_AGENT")
    private String bio_agent;

    @Column(name="ORGANIZATION")
    private String organization;

    @Column(name = "FOUND")
    private String found;

    @Column(name = "TYPE")
    private String type;

    @Column(name = "INFOR")
    private String infor;

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "id" ,columnDefinition = "serial")
    private Integer id;

   

    public Bows() {
    }


    public Integer getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getAuthor() {
        return author;
    }

    public void setAuthor(String author) {
        this.author = author;
    }

    public String getBio_agent() {
        return bio_agent;
    }

    public void setBio_agent(String bio_agent) {
        this.bio_agent = bio_agent;
    }

    public String getOrganization() {
        return organization;
    }

    public void setOrganization(String organization) {
        this.organization = organization;
    }

    public String getFound() {
        return found;
    }

    public void setFound(String found) {
        this.found = found;
    }

    public String getType() {
        return type;
    }

    public void setType(String type) {
        this.type = type;
    }

    public String getInfor() {
        return infor;
    }

    public void setInfor(String infor) {
        this.infor = infor;
    }



    
}

package com.example.umbrellacorporation.controller;
import org.springframework.web.bind.annotation.RestController;

import com.example.umbrellacorporation.model.Bows;
import com.example.umbrellacorporation.model.services.BOWSRepositorys;
import java.lang.Iterable;

import java.util.Optional;


import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;

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

@RestController
public class BowsController {
private final BOWSRepositorys bowsRepositorys;

public BowsController(final BOWSRepositorys bowsRepositorys){
    this.bowsRepositorys = bowsRepositorys;
}



public Iterable<Bows> getAllBows(){
    return this.bowsRepositorys.findAll();
}


@GetMapping("/BOWS/{id}")
public Optional<Bows> getBowsById(@PathVariable Integer id){
    return this.bowsRepositorys.findById(id);
}


@PostMapping("/BOWS")
    public Bows createNewBows(@RequestBody Bows bows) {
           
  return this.bowsRepositorys.save(bows);

    
} }

我已经多次更改数据库和 id 属性。这让我相信问题出在代码中。但我没有信心。我希望 jpa 能够识别数据库自动生成的 id，而不是出于某种原因识别 null。

Answer 1

代替这一代的策略

@GeneratedValue(strategy = GenerationType.AUTO)

尝试使用这两个中的任何一个：

@Id
@GeneratedValue(strategy = IDENTITY)
@Column(name = "id")
private Integer id;

...或者如果表是基于实体创建的...

@Id
@SequenceGenerator(name = "bows_id_sequence", sequenceName = "bows_id_sequence")
@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "bows_id_sequence")
@Column(name = "id")
private Integer id;

此外，您的 JpaRepository 必须正确，例如：

public interface BowsRepository extends JpaRepository<Bows, Integer> {
// your customs queries
}