使用hibernate框架自动生成数据库中的表

hibernate框架对JDBC进行了非常轻量级的对象封装，它将POJO与数据库表建立映射关系，是一个全自动的orm框架，它可以帮我们自动生成数据表，减少建库建表的工作。
自动生成sql语句的方法非常简单，首先新建一个maven项目，然后导入写好的实体类。
比如user

package com.zhongruan.po;

import javax.persistence.*;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;


@Entity
@Table(name = "t_user")
public class User {

    @Id
    @GeneratedValue
    private Long id;
    private String nickname;
    private String username;
    private String password;
    private String email;
    private String avatar;
    private Integer type;
    @Temporal(TemporalType.TIMESTAMP)
    private Date createTime;
    @Temporal(TemporalType.TIMESTAMP)
    private Date updateTime;

    @OneToMany(mappedBy = "user")
    private List<Blog> blogs = new ArrayList<>();

    public User() {
    }

    public Long getId() {
        return id;
    }

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

    public String getNickname() {
        return nickname;
    }

    public void setNickname(String nickname) {
        this.nickname = nickname;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getAvatar() {
        return avatar;
    }

    public void setAvatar(String avatar) {
        this.avatar = avatar;
    }

    public Integer getType() {
        return type;
    }

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

    public Date getCreateTime() {
        return createTime;
    }

    public void setCreateTime(Date createTime) {
        this.createTime = createTime;
    }

    public Date getUpdateTime() {
        return updateTime;
    }

    public void setUpdateTime(Date updateTime) {
        this.updateTime = updateTime;
    }


    public List<Blog> getBlogs() {
        return blogs;
    }

    public void setBlogs(List<Blog> blogs) {
        this.blogs = blogs;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", nickname='" + nickname + '\'' +
                ", username='" + username + '\'' +
                ", password='" + password + '\'' +
                ", email='" + email + '\'' +
                ", avatar='" + avatar + '\'' +
                ", type=" + type +
                ", createTime=" + createTime +
                ", updateTime=" + updateTime +
                '}';
    }
}

接下里在yml文件中配置端口，数据库连接（注意要提前建好数据库），比如我这里是生成在一个叫springboot的数据库中，最后设置jpa。

server:
  port: 8081
spring:
  datasource:
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql://localhost:3306/springboot?useUnicode=true&characterEncoding=utf-8&serverTimezone=UTC
    username: root
    password: 123456
  thymeleaf:
    mode: HTML
    
//自动成数据表
  jpa:
    hibernate:
      ddl-auto: update
    show-sql: true //在控制台中输出

然后运行application就行
正常启动的话会看到控制台输出了很多sql语句

然后查看我们的数据库中是否已经生成了表

成功。