package com.example.demo.entity;

import javax.persistence.*;

/*使用jpa注解配置映射关系*/

/*告诉jpa这是一个实体类和（数据表映射的类）*/

@Entity

@Table(name = "tal_user")

public class User {

    @Id /*这是主键*/

    @GeneratedValue(strategy = GenerationType.IDENTITY) /*主键自增*/

    private Integer id;

    @Column(name = "lastName",length = )/*这是和数据表对应的一个列*/

    private String lastName;

    @Column  /*省略就代表默认属性名就是列名*/

    private String email;

    public Integer getId() {

        return id;

    }

    public void setId(Integer id) {

        this.id = id;

    }

    public String getLastName() {

        return lastName;

    }

    public void setLastName(String lastName) {

        this.lastName = lastName;

    }

    public String getEmail() {

        return email;

    }

    public void setEmail(String email) {

        this.email = email;

    }

}

package com.example.demo.repository;

import com.example.demo.entity.User;

import org.springframework.data.jpa.repository.JpaRepository;

/*继承jpaRepository来完成对数据库的操作 参数是实体类型和实体类中的Id类型*/

public interface UserRepository extends JpaRepository<User, Integer> {

}

package com.example.demo.Controller;

import com.example.demo.entity.User;

import com.example.demo.repository.UserRepository;

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

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

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

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

import java.util.List;

@RestController

public class UserController {

    @Autowired

    UserRepository userRepository;

    @GetMapping("/user/{id}")

    public List<User> getUser(@PathVariable("id") Integer id){

        User user = userRepository.getOne(id);

        final List<User> users = userRepository.findAll();

        return users;

    }

    @GetMapping("/user")

    public User insertUser(User user){

        User save = userRepository.save(user);

        return save;

    }

}

spring:

  datasource:

    username: root

    password: root

    url: jdbc:mysql://localhost:3306/jpa?serverTimezone=UTC

    driver-class-name: com.mysql.cj.jdbc.Driver

  jpa:

    hibernate:

#      更新或者创建表结构

      ddl-auto: update

#      控制台显示sql

    show-sql: true

  <dependency>

            <groupId>mysql</groupId>

            <artifactId>mysql-connector-java</artifactId>

            <scope>8.0.</scope>

        </dependency>