详解非spring框架下使用querydsl的方法

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

	4.0.0
	com.test.db
	dbtest
	jar
	1.0-SNAPSHOT
	dbtest
	http://maven.apache.org
	
		4.2.1
	
	
		
			junit
			junit
			3.8.1
			test
		
		
			com.querydsl
			querydsl-sql
			${querydsl.version}
		
		
			com.querydsl
			querydsl-apt
			${querydsl.version}
		
		
			com.querydsl
			querydsl-jpa
			${querydsl.version}
		
		
			com.querydsl
			querydsl-sql-codegen
			${querydsl.version}
			provided
		
		
			org.eclipse.persistence
			org.eclipse.persistence.jpa
			2.6.0
		

		
			org.slf4j
			slf4j-log4j12
			1.6.1
		

		
			mysql
			mysql-connector-java
			8.0.11
		
		
			com.alibaba
			druid
			1.1.10
		

		
			org.hibernate
			hibernate-entitymanager
			5.4.0.Final
		
	

	
		
			
			
				com.querydsl
				querydsl-maven-plugin
				${querydsl.version}
				
					
						generate-sources
						
							jpa-export
						
						
							${project.basedir}/target/generated-sources/java
							com.test.db.entity
						
					
				
			
 			
 			
			
				org.apache.maven.plugins
				maven-compiler-plugin
				3.1
				
					1.8
					1.8
					UTF-8
				
			
		
	

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 {

  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 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 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：

  
  org.hibernate.ejb.HibernatePersistence
    
      
    	
      
			
      
      

      
      
      
      
      
      
      

      
      

      
      
    
  

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 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脚本之家。