Source code for Intro to QueryDSL article.

querydsl/src/main/java/org/baeldung/dao/PersonDao.java

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+package org.baeldung.dao;
+
+import org.baeldung.entity.Person;
+
+import java.util.List;
+
+public interface PersonDao {
+
+    public Person save(Person person);
+
+    public List<Person> findPersonsByFirstnameQueryDSL(String firstname);
+}

querydsl/src/main/java/org/baeldung/dao/PersonDaoImpl.java

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+package org.baeldung.dao;
+
+import com.mysema.query.jpa.impl.JPAQuery;
+import org.baeldung.entity.Person;
+import org.baeldung.entity.QPerson;
+import org.springframework.stereotype.Repository;
+
+import javax.persistence.EntityManager;
+import javax.persistence.PersistenceContext;
+import java.util.List;
+
+@Repository
+public class PersonDaoImpl implements PersonDao {
+
+    @PersistenceContext
+    private EntityManager em;
+
+    public Person save(Person person) {
+        em.persist(person);
+        return person;
+    }
+
+    public List<Person> findPersonsByFirstnameQueryDSL(String firstname) {
+        JPAQuery query = new JPAQuery(em);
+        QPerson person = QPerson.person;
+
+        return query.from(person).where(person.firstname.eq(firstname)).list(person);
+    }
+
+}

querydsl/src/main/java/org/baeldung/entity/Person.java

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+package org.baeldung.entity;
+
+import javax.persistence.*;
+
+@Entity
+public class Person {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    @Column
+    private String firstname;
+
+    @Column
+    private String surname;
+
+    Person() {
+    }
+
+    public Person(String firstname, String surname) {
+        this.firstname = firstname;
+        this.surname = surname;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public String getFirstname() {
+        return firstname;
+    }
+
+    public void setFirstname(String firstname) {
+        this.firstname = firstname;
+    }
+
+    public String getSurname() {
+        return surname;
+    }
+
+    public void setSurname(String surname) {
+        this.surname = surname;
+    }
+
+}

querydsl/src/main/resources/META-INF/persistence.xml

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+<?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">
+
+    <!-- PersistenceUnit for datastore -->
+    <persistence-unit name="default" transaction-type="RESOURCE_LOCAL">
+        <properties>
+            <property name="hibernate.hbm2ddl.auto" value="update" />
+            <property name="hibernate.show_sql" value="true" />
+            <property name="hibernate.transaction.flush_before_completion"
+                      value="true" />
+            <property name="hibernate.cache.provider_class" value="org.hibernate.cache.HashtableCacheProvider" />
+        </properties>
+    </persistence-unit>
+
+</persistence>

querydsl/src/main/resources/log4j.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd" >
+<log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">
+
+    <!-- Appenders -->
+    <appender name="console" class="org.apache.log4j.ConsoleAppender">
+        <param name="Target" value="System.out" />
+        <layout class="org.apache.log4j.PatternLayout">
+            <param name="ConversionPattern" value="%d{yyyy-MM-dd HH:mm:ss} [%t] %-5p: %c - %m%n" />
+        </layout>
+    </appender>
+
+    <!-- Application Loggers -->
+    <logger name="de.slackspace.tutorials">
+        <level value="debug" />
+    </logger>
+
+    <!-- Spring Loggers -->
+    <logger name="org.springframework.core">
+        <level value="info" />
+    </logger>
+
+    <logger name="org.springframework.beans">
+        <level value="info" />
+    </logger>
+
+    <logger name="org.springframework.context">
+        <level value="info" />
+    </logger>
+
+    <!-- Hibernate Loggers -->
+    <logger name="org.hibernate">
+        <level value="warn" />
+    </logger>
+
+    <!-- Root Logger -->
+    <root>
+        <priority value="warn" />
+        <appender-ref ref="console" />
+    </root>
+
+</log4j:configuration>

querydsl/src/test/java/org/baeldung/dao/PersonDaoTest.java

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+package org.baeldung.dao;
+
+import junit.framework.Assert;
+import org.baeldung.entity.Person;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+import org.springframework.test.context.transaction.TransactionConfiguration;
+import org.springframework.transaction.annotation.Transactional;
+
+
+@ContextConfiguration("/test-context.xml")
+@RunWith(SpringJUnit4ClassRunner.class)
+@Transactional
+@TransactionConfiguration(defaultRollback=true)
+public class PersonDaoTest {
+
+    @Autowired
+    private PersonDao personDao;
+
+    @Test
+    public void testCreation() {
+        personDao.save(new Person("Erich", "Gamma"));
+        Person person = new Person("Kent", "Beck");
+        personDao.save(person);
+        personDao.save(new Person("Ralph", "Johnson"));
+
+        Person personFromDb = personDao.findPersonsByFirstnameQueryDSL("Kent").get(0);
+        Assert.assertEquals(person.getId(), personFromDb.getId());
+    }
+}

querydsl/src/test/resources/db.properties

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+#In memory db
+db.username=sa
+db.password=
+db.driver=org.hsqldb.jdbcDriver
+db.url=jdbc:hsqldb:mem:app-db
+db.dialect=org.hibernate.dialect.HSQLDialect

querydsl/src/test/resources/test-context.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<beans xmlns="http://www.springframework.org/schema/beans"
+       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:mvc="http://www.springframework.org/schema/mvc"
+       xmlns:context="http://www.springframework.org/schema/context" xmlns:tx="http://www.springframework.org/schema/tx"
+       xmlns:sec="http://www.springframework.org/schema/security"
+       xmlns:aop="http://www.springframework.org/schema/aop"
+       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
+		http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
+		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd
+		http://www.springframework.org/schema/security http://www.springframework.org/schema/security/spring-security-3.0.xsd
+		http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
+		http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd"
+        >
+
+    <tx:annotation-driven />
+    <context:component-scan base-package="org.baeldung" />
+
+    <import resource="test-db.xml" />
+
+</beans>

querydsl/src/test/resources/test-db.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<beans xmlns="http://www.springframework.org/schema/beans"
+       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+       xmlns:mvc="http://www.springframework.org/schema/mvc"
+       xmlns:context="http://www.springframework.org/schema/context"
+       xmlns:tx="http://www.springframework.org/schema/tx"
+       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
+		http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
+		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd
+		http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd" default-autowire="byName">
+
+    <bean id="placeholderConfig"
+          class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
+        <property name="locations">
+            <list>
+                <value>classpath:db.properties</value>
+            </list>
+        </property>
+    </bean>
+
+    <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean" name="EntityManagerFactory">
+        <property name="persistenceUnitName" value="default"></property>
+        <property name="dataSource" ref="dataSource"></property>
+        <property name="jpaVendorAdapter">
+            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
+                <property name="showSql" value="true" />
+                <property name="generateDdl" value="true" />
+                <property name="databasePlatform" value="${db.dialect}" />
+            </bean>
+        </property>
+    </bean>
+
+    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"
+          destroy-method="close">
+        <property name="driverClassName" value="${db.driver}" />
+        <property name="url" value="${db.url}" />
+        <property name="username" value="${db.username}" />
+        <property name="password" value="${db.password}" />
+    </bean>
+
+    <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager" name="TransactionManager">
+        <property name="entityManagerFactory" ref="entityManagerFactory"></property>
+    </bean>
+
+    <tx:annotation-driven />
+
+    <bean class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor" />
+
+</beans>