如何實(shí)現(xiàn)JPA多條件復(fù)雜SQL動(dòng)態(tài)分頁(yè)查詢功能

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概述

　　ORM映射為我們帶來便利的同時(shí)，也失去了較大靈活性，如果SQL較復(fù)雜，要進(jìn)行動(dòng)態(tài)查詢，那必定是一件頭疼的事情（也可能是lz還沒發(fā)現(xiàn)好的方法），記錄下自己用的三種復(fù)雜查詢方式。

環(huán)境

springBoot

IDEA2017.3.4

JDK8

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.1.6.RELEASE</version>
    <relativePath/> <!-- lookup parent from repository -->
  </parent>
  <groupId>com.xmlxy</groupId>
  <artifactId>seasgame</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <name>seasgame</name>
  <description>Demo project for Spring Boot</description>
  <properties>
    <java.version>1.8</java.version>
  </properties>
  <dependencies>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-test</artifactId>
      <scope>test</scope>
    </dependency>
    <!--數(shù)據(jù)庫(kù)連接-->
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <scope>runtime</scope>
    </dependency>
    <!-- 熱啟動(dòng)等 -->
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-devtools</artifactId>
      <scope>runtime</scope>
      <optional>true</optional>
    </dependency>
    <!--Java bean 實(shí)體-->
    <dependency>
      <groupId>org.projectlombok</groupId>
      <artifactId>lombok</artifactId>
      <optional>true</optional>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>
    <!--swagger2 API 測(cè)試工具 -->
    <dependency>
      <groupId>io.springfox</groupId>
      <artifactId>springfox-swagger2</artifactId>
      <version>2.8.0</version>
    </dependency>
    <dependency>
      <groupId>io.springfox</groupId>
      <artifactId>springfox-swagger-ui</artifactId>
      <version>2.8.0</version>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-configuration-processor</artifactId>
      <optional>true</optional>
    </dependency>
    <!--安全框架認(rèn)證-->
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-security</artifactId>
    </dependency>
    <dependency>
      <groupId>net.sf.json-lib</groupId>
      <artifactId>json-lib</artifactId>
      <version>2.2.2</version>
      <classifier>jdk15</classifier>
    </dependency>
    <!--漢字轉(zhuǎn)拼音-->
    <dependency>
      <groupId>com.belerweb</groupId>
      <artifactId>pinyin4j</artifactId>
      <version>2.5.1</version>
    </dependency>
    <!-- thymeleaf模板 -->
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-thymeleaf</artifactId>
    </dependency>
    <!--
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-web</artifactId>
    移除嵌入式tomcat插件
    <exclusions>
      <exclusion>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-tomcat</artifactId>
      </exclusion>
    </exclusions>
  </dependency>
  -->
    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
      <version>3.1.0</version>
      <scope>provided</scope>
    </dependency>
  </dependencies>
  <packaging>war</packaging>
  <build>
    <plugins>
      <plugin>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-maven-plugin</artifactId>
      </plugin>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <configuration>
          <source>1.8</source>
          <target>1.8</target>
        </configuration>
      </plugin>
    </plugins>
    <finalName>seasgame</finalName>
    <pluginManagement>
      <plugins>
        <plugin>
          <groupId>org.apache.maven.plugins</groupId>
          <artifactId>maven-compiler-plugin</artifactId>
          <version>2.3.2</version>
          <configuration>
            <encoding>${project.build.sourceEncoding}</encoding>
            <source>1.7</source>
            <target>1.7</target>
          </configuration>
        </plugin>
        <plugin>
          <groupId>org.apache.maven.plugins</groupId>
          <artifactId>maven-surefire-plugin</artifactId>
          <configuration>
            <testFailureIgnore>true</testFailureIgnore>
          </configuration>
        </plugin>
      </plugins>
    </pluginManagement>
  </build>
</project>

@Query

當(dāng)一個(gè)SQL較為復(fù)雜時(shí)，第一個(gè)想到的就是原生的SQL語句。如果只是簡(jiǎn)單的查詢，那情況還沒這么糟糕

 @Query(value = " SELECT IFNULL(sum(right_num),0) sumRight FROM t_record WHERE record_owner_id = ?1 AND responder_no = ?2 ",nativeQuery = true)
 Map<String,Object> sumRightNum(int studentId,int responderNo);

但如果需要進(jìn)行動(dòng)態(tài)查詢，或更改，那這個(gè)value就變得復(fù)雜了。

package com.xmlxy.seasgame.dao;
import com.xmlxy.seasgame.entity.ScoreEntity;
import org.springframework.data.jpa.repository.Modifying;
import org.springframework.data.jpa.repository.Query;
import org.springframework.data.repository.CrudRepository;
import org.springframework.data.repository.query.Param;
import org.springframework.transaction.annotation.Transactional;
import java.util.List;
/**
 * 
 * Description: 
 * @author hwc
 * @date 2019/9/5
 * @return
*/ 
public interface ScoreDao extends CrudRepository<ScoreEntity,Integer>
{
  /** 
   * 
   * Description:
   *@param scoreEntity
   * @author hwc
   * @date 2019/9/6
  */
  @Transactional(rollbackFor = Exception.class)
  @Modifying
  @Query(value = "UPDATE t_score t SET " +
      "t.responder_no = CASE WHEN :#{#scoreEntity.responderNo} IS NULL THEN t.responder_no ELSE :#{#scoreEntity.responderNo} END," +
      "t.max_level = CASE WHEN :#{#scoreEntity.maxLevel} IS NULL THEN t.max_level ELSE :#{#scoreEntity.maxLevel} END," +
      "t.right_num = CASE WHEN :#{#scoreEntity.rightNum} IS NULL THEN t.right_num ELSE :#{#scoreEntity.rightNum} END," +
      "t.use_time = CASE WHEN :#{#scoreEntity.userTime} IS NULL THEN t.use_time ELSE :#{#scoreEntity.userTime} END WHERE student_id = :#{#scoreEntity.getStudentId()}",nativeQuery = true)
  void updateScore(@Param("scoreEntity") ScoreEntity scoreEntity);
}

JPQL

如果Java代碼內(nèi)發(fā)出JPQL查詢，就需要利用到EntityManager的響應(yīng)方法了。一般執(zhí)行以下流程

獲取一個(gè)EntityManager實(shí)例

調(diào)用實(shí)例的方法createQuery，創(chuàng)建一個(gè)Query實(shí)例，如果有需要可以指定檢索的最大數(shù)量和起始位置

使用Query方法getResultList執(zhí)行查詢，當(dāng)然更新和刪除操作得使用executeUpdate執(zhí)行

進(jìn)行一個(gè)復(fù)雜的動(dòng)態(tài)SQL查詢

public Page<RankEntity> getScoreByRank(int gradeId,int classId,Pageable pageable)
 {
   StringBuilder countSelectSql = new StringBuilder("");
   countSelectSql.append(" SELECT COUNT(*) ");
   countSelectSql.append(" FROM ");
   countSelectSql.append(" t_score s, ");
   countSelectSql.append(" t_student st  ");
   countSelectSql.append(" WHERE ");
   countSelectSql.append(" s.student_id = st.student_id ");
   StringBuilder selectSql = new StringBuilder();
   selectSql.append(" SELECT s.student_id,st.real_name,st.student_class,s.max_level,s.use_time,s.right_num ");
   selectSql.append(" FROM t_score s ");
   selectSql.append(" JOIN t_student st ON s.student_id = st.student_id ");
   selectSql.append(" WHERE 1 = 1 ");
   Map<String,Object> params = new HashMap<>();
   StringBuilder whereSql = new StringBuilder();
   if (gradeId != -1)
   {
     whereSql.append(" AND st.student_grade = :student_grade ");
     params.put("student_grade",gradeId);
   }
   /**班級(jí)ID*/
   if (classId != -1)
   {
     whereSql.append(" AND st.student_class = :classId ");
     params.put("classId",classId);
   }
   String orderSql = " ORDER BY s.max_level DESC,s.use_time,s.right_num ASC ";
   String countSql = new StringBuilder().append(countSelectSql).append(whereSql).toString();
   Query countQuery = entityManager.createNativeQuery(countSql);
   for (Map.Entry<String,Object> entry : params.entrySet())
   {
     countQuery.setParameter(entry.getKey(),entry.getValue());
   }
   BigInteger totalCount = (BigInteger)countQuery.getSingleResult();
   String querySql = new StringBuilder().append(selectSql).append(whereSql).append(orderSql).toString();
   Query query = entityManager.createNativeQuery(querySql,RankEntity.class);
   for (Map.Entry<String,Object> entry:params.entrySet())
   {
     query.setParameter(entry.getKey(),entry.getValue());
   }
   query.setFirstResult((int) pageable.getOffset());
   query.setMaxResults(pageable.getPageSize());
   List<RankEntity> rankEntities = query.getResultList();
   Page<RankEntity> page = new PageImpl<>(rankEntities,pageable,totalCount.longValue());
   return page;
 }

注意：如果沒有重新定義Pageable那么pageNumber必須減1，因?yàn)槭菑?開始的。

Criteria

這是一種規(guī)范查詢是以元模型的概念為基礎(chǔ)的，這個(gè)元模型可以是實(shí)體累，嵌入類，或者映射的父類，簡(jiǎn)單介紹幾個(gè)里面用到接口。

CriteraQuery是一個(gè)特定的頂層查詢對(duì)象，里面包含select，from，where，order by等各個(gè)部分，然而他只對(duì)實(shí)體類或嵌入類的標(biāo)準(zhǔn)查詢起作用。

Root標(biāo)準(zhǔn)查詢的根對(duì)象，根定義了實(shí)體類型，是你想要查詢要獲得的結(jié)果，也可以添加查詢條件，結(jié)合實(shí)體管理對(duì)象得到查詢的對(duì)象。

CriteriaBuilder接口用來構(gòu)建CritiaQuery的構(gòu)建器

StudentEntity類

package com.xmlxy.seasgame.entity;
import io.swagger.annotations.ApiModel;
import lombok.Data;
import javax.persistence.*;
import javax.print.attribute.standard.MediaSize;
import java.io.Serializable;
/**
 * 
 * Description:學(xué)生對(duì)象
 * @param
 * @author hwc
 * @date 2019/8/8  
*/
@Entity
@Table(name = "t_base_student")
@ApiModel
@Data
public class StudentEntity implements Serializable
{
  private static final long serialVersionUID = 546L;
  @Id
  @GeneratedValue(strategy = GenerationType.AUTO)
  @Column(name = "student_id")
  private Integer studentId;
  @Column(name = "student_grade")
  private Integer studentGrade;
  @Column(name = "student_class")
  private Integer studentClass;
  @Column(name = "address")
  private String address;
  @Column(name = "telephone")
  private Integer telephone;
  @Column(name = "real_name")
  private String realName;
  @Column(name = "id_number")
  private String idNumber;
  @Column(name = "study_id")
  private String studyId;
  @Column(name = "is_delete")
  private int isDelete;
  @Column(name = "uuid")
  private String uuid;
}

dao層

public interface StudentDao extends JpaRepository<StudentEntity,Integer>,JpaSpecificationExecutor
{
}

動(dòng)態(tài)查詢

 public Page<StudentEntity> getTeacherClassStudent(int pageNumber,int pageSize,int gradeId, int classId,String keyword)
  {
    pageNumber = pageNumber < 0 ? 0 : pageNumber;
    pageSize = pageSize < 0 ? 10 : pageSize;
    Specification<StudentEntity> specification = new Specification<StudentEntity>()
    {
      @Override
      public Predicate toPredicate(Root<StudentEntity> root, CriteriaQuery<?> criteriaQuery, CriteriaBuilder criteriaBuilder)
      {
        //page : 0 開始, limit : 默認(rèn)為 10
        List<Predicate> predicates = new ArrayList<>();
        predicates.add(criteriaBuilder.equal(root.get("studentGrade"),gradeId));
        predicates.add(criteriaBuilder.equal(root.get("studentClass"),classId));
        if (!Constant.isEmptyString(keyword))
        {
          predicates.add(criteriaBuilder.like(root.get("realName").as(String.class),"%" + keyword + "%"));
        }
        return criteriaBuilder.and(predicates.toArray(new Predicate[predicates.size()]));
      }
    };
    /*studentId必須是實(shí)體類屬性與數(shù)據(jù)庫(kù)對(duì)應(yīng)，否則報(bào)ropertyReferenceException異常*/
    PageRequest page = new PageRequest(pageNumber,pageSize,Sort.Direction.ASC,"studentId");
    Page<StudentEntity> pages = studentDao.findAll(specification,page);
    return pages;
  }

因?yàn)檫@個(gè)項(xiàng)目應(yīng)用比較簡(jiǎn)單，所以條件只有一個(gè)，如果條件較多，甚至可以定義一個(gè)專門的類去接收拼接參數(shù)，然后判

斷，成立就add進(jìn)去。

以上是“如何實(shí)現(xiàn)JPA多條件復(fù)雜SQL動(dòng)態(tài)分頁(yè)查詢功能”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(duì)大家有所幫助，如果還想學(xué)習(xí)更多知識(shí)，歡迎關(guān)注億速云行業(yè)資訊頻道！