SpringBoot Data Jpa基本使用

• 导入springboot data jpa依赖
• 创建实体映射类

@Entity 用来标注一个数据库对应的实体，数据库中创建的表名默认和类名一致

@Table(name=""，catalog=""，schema="") 用来标注一个数据库对应的实体，

主键需要加上注解 @Id注解

如果是自动生成需要设置生成柜子 @GeneratedValue(strategy = GenerationType.IDENTITY)

@Column(name = "menu_name") 设置属性对应的数据库字段名称

@Data
@NoArgsConstructor
@AllArgsConstructor
@Builder
@Entity
@Table(name = "sys_menu")
public class SysMenu {

  @Id
  @GeneratedValue(strategy = GenerationType.IDENTITY)
  @Column(name = "menu_id")
  private long menuId;
  @Column(name = "menu_name")
  private String menuName;
  @Column(name = "parent_id")
  private long parentId;
  @Column(name = "order_num")
  private long orderNum;
  @Column(name = "url")
  private String url;
  @Column(name = "is_delete")
  private String isDelete;
  @Column(name = "target")
  private String target;
  @Column(name = "menu_type")
  private String menuType;
  @Column(name = "visible")
  private String visible;
  @Column(name = "perms")
  private String perms;
  @Column(name = "icon")
  private String icon;
  @Column(name = "create_by")
  private String createBy;
  @Column(name = "create_time")
  private Date createTime;
  @Column(name = "update_by")
  private String updateBy;
  @Column(name = "update_time")
  private Date updateTime;
  @Column(name = "remark")
  private String remark;
}

• 新建一个dao接口 继承JpaRepository<SysMenu,Long> , JpaSpecificationExecutor** 接口

JpaRepository<T,TD> 封装了简单的crud方法

JpaSpecificationExecutor** 封装了高级查询方法

其中 T**是实体对象 TD**是主建类型

@Repository
public interface SysMenuDAO extends JpaRepository<SysMenu, Long>, JpaSpecificationExecutor<SysMenu> {
}

• 然后直接使用 调用方法crud