Java 使用合并函数时出现Spring JPA插入操作异常

人类

package com.example.springjpa.demojpa.entity;

import java.sql.Timestamp;
import java.util.Date;

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

@Entity
public class Person {

@Id
@GeneratedValue
private int id;

private String name;
private String location;
private Date birth_date;

public Person() {};



public Person(String name, String location, Date birth_date) {
    super();
    this.name = name;
    this.location = location;
    this.birth_date = birth_date;
}



public Person(int id, String name, String location, Date birth_date) {
    super();
    this.id = id;
    this.name = name;
    this.location = location;
    this.birth_date = birth_date;
}



public int getId() {
    return id;
}

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

public String getName() {
    return name;
}

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

public String getLocation() {
    return location;
}

public void setLocation(String location) {
    this.location = location;
}

public Date getBirth_date() {
    return birth_date;
}

public void setBirth_date(Timestamp birth_date) {
    this.birth_date = birth_date;
}

@Override
public String toString() {
    return "\n Person [name=" + name + ", location=" + location + ", birth_date=" + birth_date + "]";
}

}

PersonJpaDao类

package com.example.springjpa.demojpa;

import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.transaction.Transactional;

import org.springframework.stereotype.Repository;

import com.example.springjpa.demojpa.entity.Person;

@Repository
@Transactional
public class PersonJpaDao {

@PersistenceContext
EntityManager em;

public Person findById(int id) {
    return em.find(Person.class, id);
}


public Person insert(Person person){
    return em.merge(person);
}

public Person update(Person person){
    return em.merge(person);
}
}

主类

 package com.example.springjpa.demojpa;


import java.util.Date;

import javax.transaction.Transactional;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

import com.example.springjpa.demojpa.entity.Person;

@SpringBootApplication
public class DemoJpaApplication implements CommandLineRunner {

private Logger logger = LoggerFactory.getLogger(this.getClass());

public static void main(String[] args) {
    SpringApplication.run(DemoJpaApplication.class, args);
}

@Autowired
PersonJpaDao personJpaDao;

@Override
public void run(String... args) throws Exception {

    logger.info("Person yBy Id {}", personJpaDao.findById(1));

    logger.info("Update 10003 -> {}", 
            personJpaDao.update(new Person("Pieter", "Utrecht", new Date())));

}
}

当我运行main函数时，find和update工作正常，但是对于与update具有相同代码的insert操作，会引发如下异常：

原因：org.springframework.dao.DataIntegrityViolationException:无法执行语句；SQL[n/a]；约束[“PUBLIC.PERSON（ID）上的主键]；SQL语句： 插入个人（出生日期、地点、姓名、身份证）值（？，？，？）[23505-196]；嵌套异常为org.hibernate.exception.ConstraintViolationException:无法执行语句

---

原因：org.hibernate.exception.ConstraintViolationException:无法执行语句

我遇到了相同的问题，但我发现它与主键冲突，就像某些数据已经与某些（主键20）存在，实体管理器也存在冲突

---

将其设置为相同的主键（20），因为您正在使用merge方法更新和创建这两个主键，因此会导致以前存在的和通过merge方法新创建的主键冲突。请尝试在构造函数中提供id或删除数据

如何执行insert，如果id已经存在，则仅显示findById和update.update更新，否则将插入新值；我发现了错误，因为我使用的注释@GeneratedValue插入与数据库中已经存在的id冲突