application.yml

spring:
  datasource:
    username: root
    password: 123456
    url: jdbc:mysql://172.20.10.11:3306/test?characterEncoding=UTF-8&serverTimezone=UTC
    driver-class-name: com.mysql.jdbc.Driver

  jpa:
    hibernate:
#     更新或者创建数据表结构
      ddl-auto: update
#    控制台显示SQL
    show-sql: true

UserRepository

package k.repository;

import k.entity.User;
import org.springframework.data.jpa.repository.JpaRepository;

//继承JpaRepository来完成对数据库的操作
public interface UserRepository extends JpaRepository<User, Integer> {
}

User

package k.entity;


import com.fasterxml.jackson.annotation.JsonIgnoreProperties;

import javax.persistence.*;

//使用JPA注解配置映射关系
@Entity //告诉JPA这是一个实体类（和数据表映射的类）
@Table(name = "tbl_user") //@Table来指定和哪个数据表对应;如果省略默认表名就是user；
@JsonIgnoreProperties(value = {"hibernateLazyInitializer", "handler", "fieldHandler"})
public class User {

    @Id //这是一个主键
    @GeneratedValue(strategy = GenerationType.IDENTITY)//自增主键
    private Integer id;

    @Column(name = "last_name", length = 50) //这是和数据表对应的一个列
    private String lastName;
    @Column //省略默认列名就是属性名
    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;
    }
}

UserController

package k.controller;

import k.entity.User;
import k.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;

@RestController
public class UserController {

    @Autowired
    UserRepository userRepository;

    @GetMapping("/user/{id}")
    public User getUser(@PathVariable("id") Integer id) {
        User user = userRepository.getOne(id);
        return user;
    }

    @GetMapping("/user")
    public User insertUser(User user) {
        User save = userRepository.save(user);
        return save;
    }

}