1. 依赖

   <!--spring data jpa-->
   <dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-jpa</artifactId>
   </dependency>
   <!--mysql-->
   <dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <scope>runtime</scope>
   </dependency>
   

2. 配置数据源 ``` server: port: 8080 #data source spring:
   测试的时候可以不用mysql
   datasource:
   url: jdbc:mysql://127.0.0.1:3306/demo?characterEncoding=utf-8&useSSL=true
   username: root
   password: root
   driver-class-name: com.mysql.jdbc.Driver

datasource: driver-class-name: org.h2.Driver url: jdbc:h2:~/test username: sa password: h2: # 使用H2 控制台 访问页面http://localhost:8080/h2-console/，默认的数据库为jdbc:h2:mem:testdb console: enabled: true jpa: show-sql: true hibernate: ddl-auto: update #加载hibernate自动更新数据库结构

3. 创建实体类

@Data @Entity @Table(name = "tb_user") public class User implements Serializable{

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer id;

private String name;

private Integer age;

private String address;

} #我这里是把实体类单独抽成了一个名为pojo的maven项目，所以要在pojo项目中引入如下依赖 org.projectlombok lombok true org.hibernate.javax.persistence hibernate-jpa-2.1-api 1.0.2.Final

3. 创建dao

/**

• @author Mr.Guan
• @since 2019/11/20
• 用户dao 使用Spring data jpa 不需要实现类，
• 继承JpaRepository<User, Integer>即可，User为实体，Integer为id数据类型
• / public interface UserDao extends JpaRepository<User, Integer> { } ```

4. 编写serviceImpl(接口就不在此列出了)

   @Service
   public class UserServiceImpl implements UserService {
   
    @Autowired
    private UserDao userDao;
   
    @Override
    public List<User> findAll() {
        return userDao.findAll();
    }
   
    /**
     * 注意：查不到会报错
     * @param id
     * @return
     */
    @Override
    public User findById(Integer id) {
        return userDao.findById(id).get();
    }
   
    /**
     * 注意：对象所有值为空id会自增插进去
     * @param user
     * @return
     */
    @Override
    public User save(User user) {
        return userDao.save(user);
    }
   
    /**
     * 注意：修改也是调用的save方法，必须包含数据库存在的id，否则会插入
     * 即:数据存在则修改，不存在则新增，条件是数据库中是否存在此id
     * @param user
     * @return
     */
    @Override
    public User update(User user) {
        return userDao.save(user);
    }
   
    /**
     * 注意：不存在的数据删除会报错
     * @param id
     */
    @Override
    public void deleteById(Integer id) {
        userDao.deleteById(id);
    }
   }
   

5. 编写controller测试

   @RestController
   @RequestMapping("/user")
   public class UserController {
   
    @Autowired
    private UserService userService;
   
    @RequestMapping(value = "/findAll", method=RequestMethod.GET)
    public List<User> findAll(){
        return userService.findAll();
    }
   
    @RequestMapping(value = "/findById/{id}", method=RequestMethod.GET)
    public User findById(@PathVariable Integer id){
        return userService.findById(id);
    }
   
    @RequestMapping(value = "/save", method=RequestMethod.POST)
    public User save(User user){
        return userService.save(user);
    }
   
    @RequestMapping(value = "/update", method=RequestMethod.PUT)
    public User update(User user){
        return userService.update(user);
    }
   
    @RequestMapping(value = "/deleteById/{id}", method=RequestMethod.DELETE)
    public String deleteById(@PathVariable Integer id){
        userService.deleteById(id);
        return "删除成功";
    }
   }
   

源码：https://github.com/mrguanxs/boot_cloud.git 中的boot-ssh-provider项目