Jpa的@Id和@GeneratedValue的使用

import lombok.Data;
import javax.persistence.*;
import java.math.BigInteger;@Entity//将实体类首字母小写
@Table(name = "user")//要连接的数据库表名
@Data
public class UserCopy {@Id@GeneratedValue(strategy= GenerationType.IDENTITY)//    @GeneratedValue 用于标注主键的生成策略，通过strategy 属性指定。默认情况下，JPA 自动选择一个最适合底层数据库的主键生成策略：SqlServer对应identity
//    IDENTITY：采用数据库ID自增长的方式来自增主键字段，Oracle 不支持这种方式；private Integer id;private String userId;private String password;private String userName;private String userType;private BigInteger createTime;private BigInteger updateTime;}

SpringDataJPA之Repository接口

import com.hebutgo.refund.sampleUser.dto.UserListDTO;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.Modifying;
import org.springframework.data.jpa.repository.Query;
import org.springframework.data.repository.query.Param;import javax.transaction.Transactional;
import java.util.List;public interface UserCopyRepository extends JpaRepository<UserCopy,Integer> {//<表名,id（主键）属性类型是Integer>@Transactionalvoid deleteByUserId(String userId);UserCopy findByUserId(String userId);UserCopy findByUserIdAndPassword(String userId, String password);UserCopy findByUserName(String userName);//    @Transactional
//    @Modifying
//    @Query(value = "update users set user_name=:userName where user_id=:userId ", nativeQuery = true)
//    void updateNameByUserIdNative(String userId, String userName);
//
//    List<User> findByUserIdIn(List<String> userIds);
//
//    User findByToken(String token);
//
//    @Query(value = "select new com.hebutgo.refund.sampleUser.dto.UserListDTO(t1.id, t1.userId, t1.userName, t1.userType, t1.gender, t1.mobile, t1.community, t1.doorNum, t1.birthday,t1.serviceHours,t1.token) from User t1 where t1.userId = :userId and t1.password = :password")
//    List<UserListDTO> login(@Param(value = "userId")String userId, @Param(value = "password") String password);}