spring boot 数据访问3 JPA

￡神魔★判官ぃ 2022-02-16 14:29 122阅读 0赞

1、导入包

<dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-data-jpa</artifactId>
            </dependency>

spring:
       datasource:
          username: root
          password: 123456
          url: jdbc:mysql://192.168.1.16:3306/mybatis?useUnicode=true&characterEncoding=utf-8
          driver-class-name: com.mysql.jdbc.Driver
          # tomcat连接池
          tomcat:
            max-active:16
            min-idle:8
            initial-size:2
    
    spring:
        jpa:
            hibernate:
                # 更新或者创建数据表结构,一般使用none 手动创建
                ddl‐auto: update
            # 控制台显示SQL
            show‐sql: true
            properties:
                # 格式化输出的sql
                hibernate.format_sql:true
            #懒加载的一些文件，不报错
            open-in-view:false

//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；
    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;
        }
    }

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

@RestController
    public class UserController {
    
        @Autowired
        UserRepository userRepository;
    
        @GetMapping("/user/{id}")
        public User getUser(@PathVariable("id") Integer id){
            User user = userRepository.findOne(id);
            return user;
        }
    
        @GetMapping("/user")
        public User insertUser(User user){
            User save = userRepository.save(user);
            return save;
        }
    
    }