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;
+    }
+
+}