ibatis发展到MyBatis,已经越来越像Hibernate,就像有人调侃,nosql技术系发展到最后就是关系型数据库。
嘿嘿。
关于Spring data jpa的简单分页查询可以参考SpringDataJpa的官方文档。
1:实体类和表的关系
(1)表数据结构
create table T_USER ( ID VARCHAR2(50), USERID VARCHAR2(50), USERNAME VARCHAR2(50), PASSWORD VARCHAR2(50) )
(2)实体类
import java.io.Serializable; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.Id; import javax.persistence.Table; import lombok.Data; @SuppressWarnings("serial") @Entity @Table(name = "T_USER") @Data public class SimpleUserEntity implements Serializable { @Id @Column( name = "ID", length = 50,unique = true,nullable = false) private String id; @Column( name = "USERID", length = 50,unique = true,nullable = false) private String userId; @Column( name = "USERNAME", length = 50,nullable = false) private String userName; @Column( name = "PASSWORD", length = 50,nullable = false) private String passWord; }
1:new Object(feild1,feild2)的用法
(1)该方式需保证对应实体类的方法,有对应的构造方法。
public SimpleUserEntity(String userId,String userName){ this.userId = userId; this.userName = userName; }
(2)新建Repository接口
import org.springframework.data.domain.Page; import org.springframework.data.domain.Pageable; import org.springframework.data.jpa.repository.Query; import org.springframework.data.repository.PagingAndSortingRepository; public interface SimpleQueryRepository extends PagingAndSortingRepository<SimpleUserEntity, String> { @Query( value = " select new SimpleUserEntity(s.userId,s.userName) from SimpleUserEntity s ", countQuery = " select count(s) from SimpleUserEntity s" ) Page<SimpleUserEntity> userPageData(Pageable page); }
(3)测试用例
import lombok.extern.slf4j.Slf4j; import org.junit.Test; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.data.domain.Page; import org.springframework.data.domain.PageRequest; import org.springframework.data.domain.Sort; import org.springframework.data.domain.Sort.Direction; import org.springframework.data.domain.Sort.Order; import org.springframework.test.context.ActiveProfiles; import org.springframework.test.context.ContextConfiguration; import org.springframework.test.context.junit4.AbstractJUnit4SpringContextTests; import com.slfinance.shanlinbao.repository.SimpleQueryRepository; import com.slfinance.shanlinbao.repository.SimpleUserEntity; @ContextConfiguration(locations = { "classpath:/application-jpa.xml"}) @ActiveProfiles("dev") @Slf4j public class SimpleQueryRepositoryTest extends AbstractJUnit4SpringContextTests { @Autowired SimpleQueryRepository simpleQueryRepository; final int pageNum = 0, pageSize = 10; @Test public void testFindPage(){ Order order = new Order(Direction.DESC,"id"); //字段排序O PageRequest pageRequest = new PageRequest(pageNum, pageSize, new Sort(order)); Page<SimpleUserEntity> userPage = simpleQueryRepository.userPageData(pageRequest); } }
(3)返回数据
{ "id": null, "userId": "A004", "userName": "jack4", "passWord": null }
2:new Map(feild1 as otherAlias1,feild2 ad otherAlias2)
有时有些业务需要将查询出的字段更改别名,通过new Map() 方式也是思路之一。
(1)接口SimpleQueryRepository新增如下方法
@Query( value = " select new Map(s.userId as userNo,s.userName as name) from SimpleUserEntity s ", countQuery = " select count(s) from SimpleUserEntity s" ) Page<Map<String,Object>> userPageDataMap(Pageable page);
(2)SimpleQueryRepositoryTest新增方法
@Test public void testFindPageForMap(){ Order order = new Order(Direction.DESC,"id"); //字段排序O PageRequest pageRequest = new PageRequest(pageNum, pageSize, new Sort(order)); Page<Map<String,Object>> userPage = simpleQueryRepository.userPageDataMap(pageRequest); }
(3)返回数据
{ "userNo": "A004", "name": "jack4" }