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springData使用QueryDsl的示例代码

转载 作者：qq735679552 更新时间：2022-09-28 22:32:09 27 4
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这篇CFSDN的博客文章springData使用QueryDsl的示例代码由作者收集整理，如果你对这篇文章有兴趣，记得点赞哟.

经过多年,spring data jpa越来越完善,在版本迭代的过程中,会不断增加功能,今天看新的reference发现有querydsl.然后搜索到上面的参考资料2 。

无论是jpaspecificationexecutor,还是querydslpredicateexecutor,它俩都提供了使用predicate(意义相同,都是构建where子句;类不同,javax.persistence.criteria.predicate,com.querydsl.core.types.predicate)去构建查询,使用比较方便. 。

关于两者的简单使用,上面的参考资料2有介绍.文末也有总结,从概括来看,我个人认为应倾向使用querydslpredicateexecutor,querydsl不仅适用于jpa repositories,还支持mongodb. 。

下面是个例子 。

1.pom.xml 。

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<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>
   <groupid>org.exam</groupid>
   <artifactid>testjava</artifactid>
   <version> 1.0 . 0 </version>
   <name>${project.artifactid}</name>
   <properties>
     <project.build.sourceencoding>utf- 8 </project.build.sourceencoding>
     <project.reporting.outputencoding>utf- 8 </project.reporting.outputencoding>
     <java.version> 1.8 </java.version>
     <spring.version> 4.2 . 5 .release</spring.version>
     <spring-data.version>hopper-sr1</spring-data.version>
     <querydsl.version> 4.1 . 1 </querydsl.version>
     <hibernate.version> 5.1 . 0 . final </hibernate.version>
     <tomcat.version> 8.0 . 32 </tomcat.version>
     <logback.version> 1.1 . 7 </logback.version>
     <mysql.version> 5.1 . 33 </mysql.version>
     <junit.version> 4.12 </junit.version>
   </properties>
   <dependencymanagement>
     <dependencies>
       <dependency>
         <groupid>org.springframework</groupid>
         <artifactid>spring-framework-bom</artifactid>
         <version>${spring.version}</version>
         <scope> import </scope>
         <type>pom</type>
       </dependency>
       <dependency>
         <groupid>org.springframework.data</groupid>
         <artifactid>spring-data-releasetrain</artifactid>
         <version>${spring-data.version}</version>
         <scope> import </scope>
         <type>pom</type>
       </dependency>
     </dependencies>
   </dependencymanagement>
   <build>
     <plugins>
       <plugin>
         <groupid>org.apache.maven.plugins</groupid>
         <artifactid>maven-compiler-plugin</artifactid>
         <version> 3.1 </version>
         <configuration>
           <source>${java.version}</source>
           <target>${java.version}</target>
         </configuration>
       </plugin>
       <plugin>
         <groupid>com.mysema.maven</groupid>
         <artifactid>maven-apt-plugin</artifactid>
         <version> 1.0 . 4 </version>
         <executions>
           <execution>
             <phase>generate-sources</phase>
             <goals>
               <goal>process</goal>
             </goals>
             <configuration>
               <outputdirectory>target/generated-sources</outputdirectory>
               <processor>com.querydsl.apt.jpa.jpaannotationprocessor</processor>
             </configuration>
           </execution>
         </executions>
       </plugin>
     </plugins>
   </build>
   <dependencies>
     <dependency>
       <groupid>org.springframework.data</groupid>
       <artifactid>spring-data-jpa</artifactid>
     </dependency>
     <dependency>
       <groupid>org.springframework.data</groupid>
       <artifactid>spring-data-mongodb</artifactid>
     </dependency>
     <dependency>
       <groupid>com.querydsl</groupid>
       <artifactid>querydsl-apt</artifactid>
       <version>${querydsl.version}</version>
       <scope>provided</scope>
     </dependency>
     <dependency>
       <groupid>com.querydsl</groupid>
       <artifactid>querydsl-jpa</artifactid>
       <version>${querydsl.version}</version>
     </dependency>
     <dependency>
       <groupid>com.querydsl</groupid>
       <artifactid>querydsl-mongodb</artifactid>
       <version>${querydsl.version}</version>
     </dependency>
     <dependency>
       <groupid>org.hibernate</groupid>
       <artifactid>hibernate-entitymanager</artifactid>
       <version>${hibernate.version}</version>
     </dependency>
     <dependency>
       <groupid>org.apache.tomcat</groupid>
       <artifactid>tomcat-jdbc</artifactid>
       <version>${tomcat.version}</version>
     </dependency>
     <dependency>
       <groupid>org.springframework</groupid>
       <artifactid>spring-test</artifactid>
     </dependency>
     <dependency>
       <groupid>ch.qos.logback</groupid>
       <artifactid>logback-classic</artifactid>
       <version>${logback.version}</version>
     </dependency>
     <dependency>
       <groupid>mysql</groupid>
       <artifactid>mysql-connector-java</artifactid>
       <version>${mysql.version}</version>
     </dependency>
     <dependency>
       <groupid>junit</groupid>
       <artifactid>junit</artifactid>
       <version>${junit.version}</version>
     </dependency>
   </dependencies>
 
   <repositories>
     <repository>
       <id>central</id>
       <name>central repository</name>
       <url>http: //repo1.maven.org/maven2</url>
       <layout> default </layout>
       <snapshots>
         <enabled> false </enabled>
       </snapshots>
     </repository>
   </repositories>
</project>

2.domain类 。

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package org.exam.domain;
 
import org.springframework.data.mongodb.core.mapping.document;
import javax.persistence.column;
import javax.persistence.entity;
import javax.persistence.id;
import java.io.serializable;
 
@entity
@document
public class employee implements serializable {
   @id
   @column (length = 38 )
   private string id;
   @column (length = 32 )
   private string name;
   private long salary;
   private long departmentid;
   //setter和getter略
}

3.repository类 。

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package org.exam.repository.jpa;
import org.exam.domain.employee;
import org.springframework.data.querydsl.querydslpredicateexecutor;
import org.springframework.data.repository.pagingandsortingrepository;
import java.util.collection;
public interface jpaemployeerepository extends pagingandsortingrepository<employee,string>,querydslpredicateexecutor<employee>{
   collection<employee> findbyidin(collection<string> ids);
}
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package org.exam.repository.mongo;
 
import org.exam.domain.employee;
import org.springframework.data.querydsl.querydslpredicateexecutor;
import org.springframework.data.repository.pagingandsortingrepository;
import java.util.collection;
public interface mongoemployeerepository extends pagingandsortingrepository<employee, string>, querydslpredicateexecutor<employee> {
   collection<employee> findbyidin(collection<string> ids);
}

jpa有jparepository,mongodb有mongorepository,它俩都继承pagingandsortingrepository 。

3.配置类 。

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package org.exam.config;
 
import com.mongodb.mongoclient;
import com.mongodb.writeconcern;
import org.apache.tomcat.jdbc.pool.datasource;
import org.springframework.context.annotation.bean;
import org.springframework.context.annotation.configuration;
import org.springframework.context.annotation.propertysource;
import org.springframework.core.env.environment;
import org.springframework.data.jpa.repository.config.enablejparepositories;
import org.springframework.data.mongodb.mongodbfactory;
import org.springframework.data.mongodb.core.mongotemplate;
import org.springframework.data.mongodb.core.simplemongodbfactory;
import org.springframework.data.mongodb.core.writeresultchecking;
import org.springframework.data.mongodb.repository.config.enablemongorepositories;
import org.springframework.orm.jpa.jpatransactionmanager;
import org.springframework.orm.jpa.localcontainerentitymanagerfactorybean;
import org.springframework.orm.jpa.vendor.database;
import org.springframework.orm.jpa.vendor.hibernatejpavendoradapter;
import org.springframework.transaction.platformtransactionmanager;
import org.springframework.transaction.annotation.enabletransactionmanagement;
 
import javax.annotation.resource;
import java.net.unknownhostexception;
import java.util.properties;
 
@configuration
@propertysource ( "classpath:config.properties" )
@enabletransactionmanagement
@enablejparepositories (basepackages = "org.exam.repository.jpa" )
@enablemongorepositories (basepackages = "org.exam.repository.mongo" )
public class appconfig {
   @resource
   private environment env;
 
   @bean (destroymethod = "close" )
   public datasource datasource() {
     datasource datasource = new datasource();
     datasource.setdriverclassname(env.getproperty( "ds.driverclassname" ));
     datasource.seturl(env.getproperty( "ds.url" ));
     datasource.setusername(env.getproperty( "ds.username" ));
     datasource.setpassword(env.getproperty( "ds.password" ));
     datasource.setinitialsize(env.getproperty( "ds.initialsize" , integer. class ));
     datasource.setminidle(env.getproperty( "ds.minidle" , integer. class ));
     datasource.setmaxidle(env.getproperty( "ds.maxidle" , integer. class ));
     datasource.setmaxactive(env.getproperty( "ds.maxactive" , integer. class ));
     return datasource;
   }
 
   @bean
   public localcontainerentitymanagerfactorybean entitymanagerfactory() {
     hibernatejpavendoradapter jpavendoradapter = new hibernatejpavendoradapter();
     jpavendoradapter.setdatabase(database.valueof(env.getproperty( "jpa.database" )));
     jpavendoradapter.setgenerateddl(env.getproperty( "jpa.generateddl" , boolean . class ));
     jpavendoradapter.setshowsql(env.getproperty( "jpa.showsql" , boolean . class ));
     localcontainerentitymanagerfactorybean emf = new localcontainerentitymanagerfactorybean();
     emf.setdatasource(datasource());
     emf.setpackagestoscan( "org.exam.domain" );
     emf.setjpavendoradapter(jpavendoradapter);
     properties properties = new properties();
     properties.setproperty( "hibernate.default_schema" , env.getproperty( "jpa.defaultschema" ));
     emf.setjpaproperties(properties);
     return emf;
   }
 
   @bean
   public platformtransactionmanager transactionmanager() {
     return new jpatransactionmanager(entitymanagerfactory().getobject());
   }
 
   @bean
   public mongodbfactory mongodbfactory() throws unknownhostexception {
     return new simplemongodbfactory( new mongoclient(env.getproperty( "mongo.host" ), env.getproperty( "mongo.port" , integer. class )), env.getproperty( "mongo.db" ));
   }
 
   @bean
   public mongotemplate mongotemplate() throws unknownhostexception {
     mongotemplate mongotemplate = new mongotemplate(mongodbfactory());
     mongotemplate.setwriteresultchecking(writeresultchecking.exception);
     mongotemplate.setwriteconcern(writeconcern.normal);
     return mongotemplate;
   }
}

4.测试类 。

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package org.exam.repository.jpa;
 
import org.exam.config.appconfig;
import org.exam.domain.employee;
import org.junit.test;
import org.junit.runner.runwith;
import org.springframework.beans.factory.annotation.autowired;
import org.springframework.data.domain.page;
import org.springframework.data.domain.pagerequest;
import org.springframework.test.annotation.rollback;
import org.springframework.test.context.contextconfiguration;
import org.springframework.test.context.junit4.springjunit4classrunner;
import org.springframework.test.context.support.annotationconfigcontextloader;
import org.springframework.transaction.annotation.transactional;
 
import java.util.uuid;
 
@runwith (springjunit4classrunner. class )
@contextconfiguration (loader = annotationconfigcontextloader. class , classes = {appconfig. class })
@transactional (transactionmanager = "transactionmanager" ) //rollback默认为true
public class jpaemployeerepositorytest {
   @autowired
   private jpaemployeerepository jpaemployeerepository;
 
   @test
   @rollback ( false )
   public void testsave() {
     for ( int i = 0 ; i < 5 ; i++) {
       employee employee = new employee();
       employee.setid(uuid.randomuuid().tostring());
       employee.setname( "name" );
       employee.setdepartmentid( 1 + i);
       employee.setsalary( 6800 + i);
       jpaemployeerepository.save(employee);
     }
   }
 
   @test
   public void testfindall() {
     page<employee> all = jpaemployeerepository.findall( null , new pagerequest( 0 , 8 ));
     for (employee employee : all) {
       system.out.println( "employee = " + employee);
     }
   }
}
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package org.exam.repository.mongo;
import com.mongodb.mongoclient;
import org.exam.config.appconfig;
import org.exam.domain.employee;
import org.junit.test;
import org.junit.runner.runwith;
import org.springframework.beans.factory.annotation.autowired;
import org.springframework.data.domain.page;
import org.springframework.data.domain.pagerequest;
import org.springframework.data.geo.circle;
import org.springframework.data.mongodb.core.mongotemplate;
import org.springframework.test.context.contextconfiguration;
import org.springframework.test.context.junit4.springjunit4classrunner;
import org.springframework.test.context.support.annotationconfigcontextloader;
import java.net.unknownhostexception;
@runwith (springjunit4classrunner. class )
@contextconfiguration (loader = annotationconfigcontextloader. class , classes = {appconfig. class })
public class mongoemployeerepositorytest {
   @autowired
   private mongoemployeerepository mongoemployeerepository;
 
   public static void main(string[] args) throws unknownhostexception {
     mongotemplate template = new mongotemplate( new mongoclient( "127.0.0.1" , 27017 ), "test" );
     circle circle = new circle(- 73.99171 , 40.738868 , 0.01 );
 
     system.out.println();
   }
 
   @test
   public void testfindall() {
     page<employee> all = mongoemployeerepository.findall( null , new pagerequest( 0 , 8 ));
     for (employee employee : all) {
       system.out.println( "employee = " + employee);
     }
   }
}

5.其它config.properties,logback.xml文件不太重要,篇幅关系就省略. 。

  。

再了解一下比较大的需求,从几张表来取几个字段的数据,返回分页排序数据. 。

1.在appconfig注册jpaqueryfactory bean 。

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@bean
public jpaqueryfactory jpaqueryfactory(entitymanager entitymanager) {
   return new jpaqueryfactory( new hqltemplates(), entitymanager);
}

2.建一个dto(数据传输对象) 。

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public class userdto {
   private string empname;
   private string deptname;
   private long salary;
   //setter,getter略
}

3.查询例子测试 。

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private page<userdto> findall(string empname,pageable pageable) {
   qemployee qemp = qemployee.employee;
   qdepartment qdep = qdepartment.department;
   list<predicate> criteria = new arraylist<>();
   if (stringutils.hastext(empname)){
     criteria.add(qemp.name.eq(empname.trim()));
   }
 
   jpaquery<?> query = jpaqueryfactory.from(qemp).innerjoin(qdep).on(qemp.deptid.eq(qdep.id)).where(criteria.toarray( new predicate[criteria.size()]));
   long total = query.fetchcount();
   list<userdto> content;
   if (pageable == null || total > pageable.getoffset()) {
     map<string, simpleexpression<?>> map = new hashmap<>();
     map.put( "deptname" , qdep.name);
     map.put( "empname" , qemp.name);
     map.put( "salary" , qemp.salary);
     content = querydslutils.applypagination(pageable, query).select(projections.bean(userdto. class , map)).fetch();
   } else {
     content = collections.emptylist();
   }
   return new pageimpl<>(content, pageable, total);
}
 
@test
public void test() {
   pageable pageable = new pagerequest( 0 , 10 , new qsort( new orderspecifier<>(order.desc, qemployee.employee.salary), new orderspecifier<>(order.asc, qdepartment.department.name)));
   page<userdto> page = findall( "name" , pageable);
   for (userdto userdto : page) {
     system.out.println( "userdto = " + userdto);
   }
}

参考资料 。

1:http://docs.spring.io/spring-data/jpa/docs/1.10.x/reference/pdf/spring-data-jpa-reference.pdf  。

2:https://spring.io/blog/2011/04/26/advanced-spring-data-jpa-specifications-and-querydsl/  。

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持我.

原文链接：https://blog.csdn.net/xiejx618/article/details/51480265 。

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