SpringBoot学习笔记之操作mysql数据库

spring-data-jpa

Spring-data-jpa依赖于Hibernate
在pom.xml中引入spring-data-jpa与mysql的依赖

    org.springframework.boot
    spring-boot-starter-data-jpa



   mysql
   mysql-connector-java

在主配置文件中添加配置

spring:
  datasource:
    driver-class-name: com.mysql.jdbc.Driver
    url : jdbc:mysql://127.0.0.1:3306/testdb
    username: root
    password: root
  jpa:
    hibernate:
      ddl-auto: create
    show-sql: true

spring.jpa.properties.hibernate.ddl.auto是hibernate的配置属性,主要作用是：自动创建、更新、验证数据库表结构
创建实体类

补充说明

@id的导入要使用

import javax.persistence.Id;
否则启动会报错

@Entity//实体类
public class User{

    @Id//主键
    @GeneratedValue//自增
    private Integer id;
    private String name;
    private Integer age;
    //必须要有一个空参构造器
    public User() {
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name= name;
    }

    public Integer getId() {
        return id;
    }

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

dao层

public interface UserRepostory extends JpaRepository {

    UserfindByName(String name);


    @Query("from User u where u.id=:id")
    User (@Param("id") Integer id);

}

接口JpaRepository的源代码

JpaRepository