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小編給大家分享一下Spring Data Jpa多表查詢?nèi)绾畏祷刈远x實(shí)體,相信大部分人都還不怎么了解,因此分享這篇文章給大家參考一下,希望大家閱讀完這篇文章后大有收獲,下面讓我們一起去了解一下吧!
比如來看一下這樣的一條SQL語句,這是一個三張表的多表查詢,顯然在JPA中用一個實(shí)體類是接受不了這些參數(shù)的
select t1.id as chapterId , t1.name as chapterName , t2.id as unitId, t2.name as unitName , t3.id as lessonId, t3.name as lessonName from t_chapter t1 LEFT JOIN t_unit t2 on t1.id =t2.chapter_id LEFT JOIN t_lession t3 on t3.unit_id =t2.id where t1.id= '4028b4816305ea91016305eec24f0000' and t2.id='4028b4816305f1a6016305f423180000' and t3.id= '4028b4816306007b016306020bb80000';
/** * Created by ZhuPengWei on 2018/5/11. */ public interface TestRepository extends JpaRepository<ProductInfo, String > { @Query( value = "select \n" + "t1.id as chapterId ,t1.name as chapterName ,t2.id as unitId,t2.name as unitName ,t3.id as lessonId,t3.name as lessonName\n" + "from t_chapter t1\n" + "LEFT JOIN t_unit t2 on t1.id =t2.chapter_id\n" + "LEFT JOIN t_lession t3 on t3.unit_id =t2.id \n" + "where t1.id= :chapterId \n" + "and t2.id=:unitId \n" + "and t3.id= :lessonId", nativeQuery = true ) List<Object[]> select(@Param("chapterId") String chapterId, @Param("unitId") String unitId, @Param("lessonId") String lessonId); }
/** * Created by ZhuPengWei on 2018/5/11. */ @RunWith(SpringRunner.class) @SpringBootTest public class TestRepositoryTest { @Autowired private TestRepository testRepository; @Test public void select() throws Exception { List<Object[]> select = testRepository.select("4028b4816305ea91016305eec24f0000", "4028b4816305f1a6016305f423180000", "4028b4816306007b016306020bb80000"); List<TestView> testViews = castEntity(select, TestView.class); Assert.assertTrue(testViews.size() > 0); } //轉(zhuǎn)換實(shí)體類 public static <T> List<T> castEntity(List<Object[]> list, Class<T> clazz) throws Exception { List<T> returnList = new ArrayList<T>(); if(CollectionUtils.isEmpty(list)){ return returnList; } Object[] co = list.get(0); Class[] c2 = new Class[co.length]; //確定構(gòu)造方法 for (int i = 0; i < co.length; i++) { if(co[i]!=null){ c2[i] = co[i].getClass(); }else { c2[i]=String.class; } } for (Object[] o : list) { Constructor<T> constructor = clazz.getConstructor(c2); returnList.add(constructor.newInstance(o)); } return returnList; }
/** * Created by ZhuPengWei on 2018/5/11. */ @Data public class TestView { private String chapterId; private String chapterName; private String unitId; private String unitName; private String lessonId; private String lessonName; public TestView() { } public TestView(String chapterId, String chapterName, String unitId, String unitName, String lessonId, String lessonName) { this.chapterId = chapterId; this.chapterName = chapterName; this.unitId = unitId; this.unitName = unitName; this.lessonId = lessonId; this.lessonName = lessonName; } }
需要注意的是 SQL語句的字段順序一定要與實(shí)體類字段的順序保持一致,否則會出現(xiàn)參數(shù)封裝錯誤的情況
這兩天開了一個新項目,使用SpringBoot+SpringData, 剛做了一個小功能,都是一張表的操作沒什么問題,今天設(shè)計到了兩張表聯(lián)查,兩張表各取了幾個字段,組合成了一個vo, 當(dāng)我用原生sql查詢時報出 “找不到轉(zhuǎn)換器”,當(dāng)我用JPQL查詢時,報出 xxx is not mapped.。 著實(shí)浪費(fèi)了些時間。
其實(shí)最大的根本原因在于, 當(dāng)使用JPQL 查詢時,我們 FROM 的表名就不能是實(shí)體上@Table 注解中的表名,而是對應(yīng)的實(shí)體的類名,記住是類名,并且查詢的字段要是 實(shí)體類的屬性,而不是數(shù)據(jù)庫字段。切記。
package com.wisdombud.dama.quality.datasource.pojo; import java.io.Serializable; import java.util.Date; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.SequenceGenerator; import javax.persistence.Table; import javax.validation.constraints.NotBlank; import com.fasterxml.jackson.annotation.JsonFormat; import lombok.ToString; @Entity @Table(name = "DATA_SOURCE") @SequenceGenerator(name = "ID_SEQ", sequenceName = "SEQ_DATA_SOURCE", allocationSize = 1) @ToString public class DataSourcePojo implements Serializable{ private static final long serialVersionUID = 4658654420795590006L; private Long id; @NotBlank(message = "數(shù)據(jù)源名稱不能為空!") private String name; @NotBlank(message = "ip地址不能為空!") private String ip; @NotBlank(message = "端口號不能為空!") private String port; @NotBlank(message = "服務(wù)名不能為空!") private String serviceName; @NotBlank(message = "用戶名不能為空!") private String userName; @NotBlank(message = "密碼不能為空!") private String password; private String managerBranch; private String leadingCadre; private String phone; private Long sortIndex; private String remark; private Long createUserId; private String createUserName; @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8") private Date createTime; private Date lastUpdateTime; private String re1; private String re2; private String re3; private String re4; @Id @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "ID_SEQ") @Column(name = "ID", unique = true, nullable = false, precision = 18, scale = 0) public Long getId() { return id; } public void setId(Long id) { this.id = id; } @Column(name = "NAME") public String getName() { return name; } public void setName(String name) { this.name = name; } @Column(name = "IP") public String getIp() { return ip; } public void setIp(String ip) { this.ip = ip; } @Column(name = "PORT") public String getPort() { return port; } public void setPort(String port) { this.port = port; } @Column(name = "SERVICE_NAME") public String getServiceName() { return serviceName; } public void setServiceName(String serviceName) { this.serviceName = serviceName; } @Column(name = "USER_NAME") public String getUserName() { return userName; } public void setUserName(String userName) { this.userName = userName; } @Column(name = "PASSWORD") public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } @Column(name = "MANAGER_BRANCH") public String getManagerBranch() { return managerBranch; } public void setManagerBranch(String managerBranch) { this.managerBranch = managerBranch; } @Column(name = "LEADING_CADRE") public String getLeadingCadre() { return leadingCadre; } public void setLeadingCadre(String leadingCadre) { this.leadingCadre = leadingCadre; } @Column(name = "PHONE") public String getPhone() { return phone; } public void setPhone(String phone) { this.phone = phone; } @Column(name = "SORT_INDEX") public Long getSortIndex() { return sortIndex; } public void setSortIndex(Long sortIndex) { this.sortIndex = sortIndex; } @Column(name = "REMARK") public String getRemark() { return remark; } public void setRemark(String remark) { this.remark = remark; } @Column(name = "CREATE_USER_ID") public Long getCreateUserId() { return createUserId; } public void setCreateUserId(Long createUserId) { this.createUserId = createUserId; } @Column(name = "CREATE_USER_NAME") public String getCreateUserName() { return createUserName; } public void setCreateUserName(String createUserName) { this.createUserName = createUserName; } @Column(name = "CREATE_TIME") public Date getCreateTime() { return createTime; } public void setCreateTime(Date createTime) { this.createTime = createTime; } @Column(name = "LAST_UPDATE_TIME") public Date getLastUpdateTime() { return lastUpdateTime; } public void setLastUpdateTime(Date lastUpdateTime) { this.lastUpdateTime = lastUpdateTime; } @Column(name = "RE1") public String getRe1() { return re1; } public void setRe1(String re1) { this.re1 = re1; } @Column(name = "RE2") public String getRe2() { return re2; } public void setRe2(String re2) { this.re2 = re2; } @Column(name = "RE3") public String getRe3() { return re3; } public void setRe3(String re3) { this.re3 = re3; } @Column(name = "RE4") public String getRe4() { return re4; } public void setRe4(String re4) { this.re4 = re4; } }
package com.wisdombud.dama.quality.datasource.tablerelation.pojo; import java.io.Serializable; import java.util.Date; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.SequenceGenerator; import javax.persistence.Table; import lombok.ToString; /** * 表關(guān)系實(shí)體 * @author qiaoyutao * @Date: 2019年7月4日 上午11:40:10 */ @Entity @Table(name = "TABLE_RELATION") @SequenceGenerator(name = "ID_SEQ", sequenceName = "SEQ_TABLE_RELATION", allocationSize = 1) @ToString public class TableRelationPojo implements Serializable{ private static final long serialVersionUID = -9058973373224769393L; private Long id; private Long dataSourceId; private String tableName; private String columnName; private String relationTableName; private String relationColumnName; private String remark; private Long createUserId; private String createUserName; private Date createTime; private Date lastUpdateTime; private String re1; private String re2; private String re3; private String re4; @Id @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "ID_SEQ") @Column(name = "ID", unique = true, nullable = false, precision = 18, scale = 0) public Long getId() { return id; } public void setId(Long id) { this.id = id; } @Column(name = "DATA_SOURCE_ID") public Long getDataSourceId() { return dataSourceId; } public void setDataSourceId(Long dataSourceId) { this.dataSourceId = dataSourceId; } @Column(name = "TABLE_NAME") public String getTableName() { return tableName; } public void setTableName(String tableName) { this.tableName = tableName; } @Column(name = "COLUMN_NAME") public String getColumnName() { return columnName; } public void setColumnName(String columnName) { this.columnName = columnName; } @Column(name = "RELATION_TABLE_NAME") public String getRelationTableName() { return relationTableName; } public void setRelationTableName(String relationTableName) { this.relationTableName = relationTableName; } @Column(name = "RELATION_COLUMN_NAME") public String getRelationColumnName() { return relationColumnName; } public void setRelationColumnName(String relationColumnName) { this.relationColumnName = relationColumnName; } @Column(name = "REMARK") public String getRemark() { return remark; } public void setRemark(String remark) { this.remark = remark; } @Column(name = "CREATE_USER_ID") public Long getCreateUserId() { return createUserId; } public void setCreateUserId(Long createUserId) { this.createUserId = createUserId; } @Column(name = "CREATE_USER_NAME") public String getCreateUserName() { return createUserName; } public void setCreateUserName(String createUserName) { this.createUserName = createUserName; } @Column(name = "CREATE_TIME") public Date getCreateTime() { return createTime; } public void setCreateTime(Date createTime) { this.createTime = createTime; } @Column(name = "LAST_UPDATE_TIME") public Date getLastUpdateTime() { return lastUpdateTime; } public void setLastUpdateTime(Date lastUpdateTime) { this.lastUpdateTime = lastUpdateTime; } @Column(name = "RE1") public String getRe1() { return re1; } public void setRe1(String re1) { this.re1 = re1; } @Column(name = "RE2") public String getRe2() { return re2; } public void setRe2(String re2) { this.re2 = re2; } @Column(name = "RE3") public String getRe3() { return re3; } public void setRe3(String re3) { this.re3 = re3; } @Column(name = "RE4") public String getRe4() { return re4; } public void setRe4(String re4) { this.re4 = re4; } }
package com.wisdombud.dama.quality.datasource.tablerelation.dao; import org.springframework.data.domain.Page; import org.springframework.data.domain.Pageable; import org.springframework.data.jpa.repository.JpaRepository; import org.springframework.data.jpa.repository.JpaSpecificationExecutor; import org.springframework.data.jpa.repository.Query; import com.wisdombud.dama.quality.datasource.tablerelation.pojo.TableRelationPojo; import com.wisdombud.dama.quality.datasource.tablerelation.vo.TableRelationGridVo; public interface TableRelationDao extends JpaRepository<TableRelationPojo, Long>, JpaSpecificationExecutor<TableRelationPojo>{ // 這里使用JPQL來寫的, 區(qū)別就是 new 一個vo名,最好帶上全路徑,并且vo中要有有參構(gòu)造器,構(gòu)造器簽名要與查詢的字段一致, 查詢的屬性都是實(shí)體類中的屬性名,不是數(shù)據(jù)庫的字段名,這點(diǎn)切記。 @Query(value = "SELECT new com.wisdombud.dama.quality.datasource.tablerelation.vo.TableRelationGridVo(re.id, " + "ds.name, re.tableName, re.columnName, " + "re.relationTableName, re.relationColumnName, " + "re.createTime) " + "FROM TableRelationPojo re left join DataSourcePojo ds on re.dataSourceId = ds.id") public Page<TableRelationGridVo> page(Pageable pageable); }
以上是“Spring Data Jpa多表查詢?nèi)绾畏祷刈远x實(shí)體”這篇文章的所有內(nèi)容,感謝各位的閱讀!相信大家都有了一定的了解,希望分享的內(nèi)容對大家有所幫助,如果還想學(xué)習(xí)更多知識,歡迎關(guān)注億速云行業(yè)資訊頻道!
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