详解非spring框架下使用querydsl的方法

三叶草

Querydsl是一个采用API代替拼凑字符串来构造查询语句，可跟 Hibernate 和 JPA 等框架结合使用。本文介绍的是非spring环境下querydsl JPA整合使用，感兴趣的小伙伴们可以参考一下
querydsl是一个采用api代替拼凑字符串来构造查询语句，可跟 hibernate 和 jpa 等框架结合使用。网上很多教程都是结合spring jpa框架下使用的教程，本文介绍的是非spring环境下querydsl jpa整合使用。
1、使用eclipse生成jpa实体类，idea也能生成同样jpa实体类。
鼠标右键打开jpa tools工具：

创建数据库链接：

选择那些数据库表需要生成jpa实体类：

关联表生成：

设置实体生成属性：

单个实体属性修改

生成的jpa实体类adminlog.java

package com.test.db.entity;
 
import java.io.serializable;
import javax.persistence.*;
import java.util.date;
 
 
/**
 * the persistent class for the admin_log database table.
 * 
 */
@entity
@table(name="admin_log")
@namedquery(name="adminlog.findall", query="select a from adminlog a")
public class adminlog implements serializable {
  private static final long serialversionuid = 1l;
 
  @id
  @generatedvalue(strategy=generationtype.auto)
  @column(unique=true, nullable=false)
  private string id;
 
  @column(name="action_id", length=20)
  private string actionid;
 
  @column(name="client_ip", length=15)
  private string clientip;
 
  @column(name="controller_id", length=20)
  private string controllerid;
 
  @temporal(temporaltype.timestamp)
  @column(name="create_date")
  private date createdate;
 
  @column(name="create_user", length=50)
  private string createuser;
 
  @column(name="func_name", length=50)
  private string funcname;
 
  @column(name="module_name", length=50)
  private string modulename;
 
  @column(name="right_name", length=50)
  private string rightname;
 
  @column(length=200)
  private string url;
 
  public adminlog() {
  }
 
  public string getid() {
    return this.id;
  }
 
  public void setid(string id) {
    this.id = id;
  }
 
  public string getactionid() {
    return this.actionid;
  }
 
  public void setactionid(string actionid) {
    this.actionid = actionid;
  }
 
  public string getclientip() {
    return this.clientip;
  }
 
  public void setclientip(string clientip) {
    this.clientip = clientip;
  }
 
  public string getcontrollerid() {
    return this.controllerid;
  }
 
  public void setcontrollerid(string controllerid) {
    this.controllerid = controllerid;
  }
 
  public date getcreatedate() {
    return this.createdate;
  }
 
  public void setcreatedate(date createdate) {
    this.createdate = createdate;
  }
 
  public string getcreateuser() {
    return this.createuser;
  }
 
  public void setcreateuser(string createuser) {
    this.createuser = createuser;
  }
 
  public string getfuncname() {
    return this.funcname;
  }
 
  public void setfuncname(string funcname) {
    this.funcname = funcname;
  }
 
  public string getmodulename() {
    return this.modulename;
  }
 
  public void setmodulename(string modulename) {
    this.modulename = modulename;
  }
 
  public string getrightname() {
    return this.rightname;
  }
 
  public void setrightname(string rightname) {
    this.rightname = rightname;
  }
 
  public string geturl() {
    return this.url;
  }
 
  public void seturl(string url) {
    this.url = url;
  }
 
}

2、生成querydsl查询类
maven pom.xml文件

<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/maven-v4_0_0.xsd">
  <modelversion>4.0.0</modelversion>
  <groupid>com.test.db</groupid>
  <artifactid>dbtest</artifactid>
  <packaging>jar</packaging>
  <version>1.0-snapshot</version>
  <name>dbtest</name>
  <url>http://maven.apache.org</url>
  <properties>
    <querydsl.version>4.2.1</querydsl.version>
  </properties>
  <dependencies>
    <dependency>
      <groupid>junit</groupid>
      <artifactid>junit</artifactid>
      <version>3.8.1</version>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupid>com.querydsl</groupid>
      <artifactid>querydsl-sql</artifactid>
      <version>${querydsl.version}</version>
    </dependency>
    <dependency>
      <groupid>com.querydsl</groupid>
      <artifactid>querydsl-apt</artifactid>
      <version>${querydsl.version}</version>
    </dependency>
    <dependency>
      <groupid>com.querydsl</groupid>
      <artifactid>querydsl-jpa</artifactid>
      <version>${querydsl.version}</version>
    </dependency>
    <dependency>
      <groupid>com.querydsl</groupid>
      <artifactid>querydsl-sql-codegen</artifactid>
      <version>${querydsl.version}</version>
      <scope>provided</scope>
    </dependency>
    <dependency>
      <groupid>org.eclipse.persistence</groupid>
      <artifactid>org.eclipse.persistence.jpa</artifactid>
      <version>2.6.0</version>
    </dependency>
 
    <dependency>
      <groupid>org.slf4j</groupid>
      <artifactid>slf4j-log4j12</artifactid>
      <version>1.6.1</version>
    </dependency>
 
    <dependency>
      <groupid>mysql</groupid>
      <artifactid>mysql-connector-java</artifactid>
      <version>8.0.11</version>
    </dependency>
    <dependency>
      <groupid>com.alibaba</groupid>
      <artifactid>druid</artifactid>
      <version>1.1.10</version>
    </dependency>
 
    <dependency>
      <groupid>org.hibernate</groupid>
      <artifactid>hibernate-entitymanager</artifactid>
      <version>5.4.0.final</version>
    </dependency>
  </dependencies>
 
  <build>
    <plugins>
      <!-- 生成jpa实体插件 -->
      <plugin>
        <groupid>com.querydsl</groupid>
        <artifactid>querydsl-maven-plugin</artifactid>
        <version>${querydsl.version}</version>
        <executions>
          <execution>
            <phase>generate-sources</phase>
            <goals>
              <goal>jpa-export</goal>
            </goals>
            <configuration>
              <targetfolder>${project.basedir}/target/generated-sources/java</targetfolder>
              <packages>com.test.db.entity</packages>
            </configuration>
          </execution>
        </executions>
      </plugin>
      <!-- 生成jpa实体插件 -->
      <!-- 
      <plugin>
       <groupid>com.mysema.maven</groupid>
       <artifactid>apt-maven-plugin</artifactid>
       <version>1.1.3</version>
       <executions>
      <execution>
       <goals>
        <goal>process</goal>
       </goals>
       <configuration>
        <outputdirectory>target/generated-sources/java</outputdirectory>
        <processor>com.querydsl.apt.jpa.jpaannotationprocessor</processor>
       </configuration>
      </execution>
       </executions>
      </plugin>
       -->
      <plugin>
        <groupid>org.apache.maven.plugins</groupid>
        <artifactid>maven-compiler-plugin</artifactid>
        <version>3.1</version>
        <configuration>
          <source>1.8</source>
          <target>1.8</target>
          <encoding>utf-8</encoding>
        </configuration>
      </plugin>
    </plugins>
  </build>
</project>

执行命令mvn compile或mvn eclipse:eclipse生成jpa实体对应的querydsl查询类
adminlog.java对应的querydsl对应查询类

package com.test.db.entity;
 
import static com.querydsl.core.types.pathmetadatafactory.*;
 
import com.querydsl.core.types.dsl.*;
 
import com.querydsl.core.types.pathmetadata;
import javax.annotation.generated;
import com.querydsl.core.types.path;
 
 
/**
 * qadminlog is a querydsl query type for adminlog
 */
@generated("com.querydsl.codegen.entityserializer")
public class qadminlog extends entitypathbase<adminlog> {
 
  private static final long serialversionuid = 392071999l;
 
  public static final qadminlog adminlog = new qadminlog("adminlog");
 
  public final stringpath actionid = createstring("actionid");
 
  public final stringpath clientip = createstring("clientip");
 
  public final stringpath controllerid = createstring("controllerid");
 
  public final datetimepath<java.util.date> createdate = createdatetime("createdate", java.util.date.class);
 
  public final stringpath createuser = createstring("createuser");
 
  public final stringpath funcname = createstring("funcname");
 
  public final stringpath id = createstring("id");
 
  public final stringpath modulename = createstring("modulename");
 
  public final stringpath rightname = createstring("rightname");
 
  public final stringpath url = createstring("url");
 
  public qadminlog(string variable) {
  super(adminlog.class, forvariable(variable));
  }
 
  public qadminlog(path<? extends adminlog> path) {
  super(path.gettype(), path.getmetadata());
  }
 
  public qadminlog(pathmetadata metadata) {
  super(adminlog.class, metadata);
  }
 
}

3、查询例子
jpa持久化meta-inf\persistence.xml配置文件，entitymanagerfactory创建实例时，需要读取该配置文件：

<?xml version="1.0" encoding="utf-8"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence"
  xmlns:xsi="http://www.w3.org/2001/xmlschema-instance"
  xsi:schemalocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd"
  version="2.0">
  <persistence-unit name="jpa" transaction-type="resource_local">
  <provider>org.hibernate.ejb.hibernatepersistence</provider>
  <properties>
    <!-- .mysqlinnodbdialect -->
    <property name="hibernate.dialect" value="org.hibernate.dialect.mysql8dialect"/>
    <property name="javax.persistence.jdbc.driver" value="com.mysql.cj.jdbc.driver" />
      <property name="javax.persistence.jdbc.url" value="jdbc:mysql://127.0.0.1:3306/yiiboot?useunicode=true&characterencoding=utf-8&servertimezone=asia/shanghai&usessl=true" />
    <property name="javax.persistence.jdbc.user" value="root" />
    <property name="javax.persistence.jdbc.password" value="123" />
 
    <property name="connection.provider_class" value="com.alibaba.druid.support.hibernate.druidconnectionprovider" />
    <!-- 配置初始化大小、最小、最大 -->
    <property name="initialsize" value="1" />
    <property name="minidle" value="1" />
    <property name="maxactive" value="20" />
    <!-- 配置获取连接等待超时的时间 -->
    <property name="maxwait" value="60000" />
 
    <!-- 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒 -->
    <property name="timebetweenevictionrunsmillis" value="60000" />
 
    <!-- 配置一个连接在池中最小生存的时间，单位是毫秒 -->
    <property name="minevictableidletimemillis" value="300000" />
  </properties>
  </persistence-unit>
</persistence>

测试代码

package com.test.db.main;
 
import java.util.list;
import javax.persistence.entitymanagerfactory;
import javax.persistence.persistence;
import com.querydsl.jpa.impl.jpaqueryfactory;
import com.test.db.entity.adminmodule;
import com.test.db.entity.qadminmodule;
 
public class jpatest {
  public static void main(string[] args) throws exception{
    string persistenceunitname = "jpa";
    entitymanagerfactory entitymanagerfactory = 
    persistence.createentitymanagerfactory(persistenceunitname);
    jpaqueryfactory queryfactory = new jpaqueryfactory(entitymanagerfactory.createentitymanager());
    qadminmodule adminmodule = qadminmodule.adminmodule;
    list<adminmodule> list = queryfactory.selectfrom(adminmodule).fetch();
    list.foreach(module->{
      system.out.println(module.getid() + "," + module.getdisplaylabel() + "," + module.getcreatedate());
    });
  }
}

querydsl官方文档：http://www.querydsl.com/static/querydsl/latest/reference/html/ch02.html#jpa_integration
java类库：https://www.21doc.net/java/awesomejava#database
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CodeAE代码之家。
原文链接：https://my.oschina.net/penngo/blog/2998232

[Java] 详解非spring框架下使用querydsl的方法

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三叶草 LV3