Java 學習記錄132 — 員工管理系統專案練習-Create JPA Entity

在 src\main\java 新增四個資料夾

分別是 controller、exception、model、repository

在 model 裡新增 Employee.java

package com.example.springbootbackend.model;
import javax.persistence.*;
@Entity
@Table(name = "employees")
public class Employee {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;
    private String firstName;
    private String lastName;
    private String emailId;
    public Employee() {
    }
    public Employee(String firstName, String lastName, String emailId) {
        this.firstName = firstName;
        this.lastName = lastName;
        this.emailId = emailId;
    }
    public Long getId() {
        return id;
    }
    public void setId(Long id) {
        this.id = id;
    }
    public String getFirstName() {
        return firstName;
    }
    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }
    public String getLastName() {
        return lastName;
    }
    public void setLastName(String lastName) {
        this.lastName = lastName;
    }
    public String getemailId() {
        return emailId;
    }
    public void setemailId(String emailId) {
        this.emailId = emailId;
    }
}

若是用 Intellij 的話，在 @Table(name = "employees") 應該會報錯

解決方法

All your domain models must be annotated with @Entity annotation. It is used to mark the class as a persistent Java class.

@Table annotation is used to provide the details of the table that this entity will be mapped to.

@Id annotation is used to define the primary key.

@GeneratedValue annotation is used to define the primary key generation strategy.

沒有註明的話就是自增長

等同於 @GeneratedValue(strategy=GenerationType.AUTO)

參考1、參考2

GenerationType.AUTO vs GenerationType.IDENTITY in hibernate

參考項目來源