SpringBoot整合SpringDataJpa 之 CrudRepository

CrudRepository接口,主要是完成一些增删改查的操作。注意：CrudRepository接口继承了Repository接口

示例： 准备工作：

实体类：

@Entity
@Table(name = "tb_dept")
public class Dept {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Integer deptno;

    @Column
    private String dname;

    @Column
    private String loc;

    //……getter/setter、默认构造方法、全参构造方法
}

第一步：创建Maven项目，添加依赖：

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


    mysql
    mysql-connector-java
    runtime


    org.springframework.boot
    spring-boot-starter-test
    test


    junit
    junit
    4.12
    test

第二步：修改application.yml：

spring:
  datasource:
    url: jdbc:mysql://localhost:3306/db_test?useSSL=false&serverTimezone=GMT%2B8&useUnicode=true&characterEncoding=UTF8&autoReconnect=true&failOverReadOnly=false
    username: root
    password: root
    driver-class-name: com.mysql.cj.jdbc.Driver
  jpa:
    hibernate:
      ddl-auto: update
    properties:
      hibernate:
        enable_lazy_load_no_trans: true
    show-sql: true

第三步：编写接口DeptDao.java：

public interface DeptDao extends CrudRepository {

}

第四步：提供测试代码：

@RunWith(SpringRunner.class)
@SpringBootTest
@EnableAutoConfiguration
public class DeptDaoTest {
    @Autowired
    private DeptDao deptDao;

    @Test
    public void save() {
        Dept dept = new Dept(123, "123", "123");
        Dept res = deptDao.save(dept);
        System.out.println(res);
    }

    @Test
    public void update() {
        Dept dept = new Dept(4, "aaa", "ddd");
        Dept res = deptDao.save(dept);
        System.out.println(res);
    }

    @Test
    public void delete() {
        deptDao.deleteById(3);
    }

    @Test
    public void findById() {
        Optional optional = deptDao.findById(2);
        System.out.println(optional.get());
    }
}