Merge pull request #6715 from vimde/master

BAEL-2857 Defining a JPA Entity

persistence-modules/java-jpa/src/main/java/com/baeldung/jpa/entity/Student.java

@@ -0,0 +1,75 @@
+package com.baeldung.jpa.entity;
+
+import java.util.Date;
+
+import javax.persistence.Column;
+import javax.persistence.Entity;
+import javax.persistence.EnumType;
+import javax.persistence.Enumerated;
+import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
+import javax.persistence.Id;
+import javax.persistence.Table;
+import javax.persistence.Temporal;
+import javax.persistence.TemporalType;
+import javax.persistence.Transient;
+
+import com.baeldung.util.Gender;
+
+@Entity
+@Table(name="STUDENT")
+public class Student {
+
+	@Id
+	@GeneratedValue(strategy = GenerationType.AUTO)
+	private Long id;
+	@Column(name = "STUDENT_NAME", length = 50, nullable = false, unique = false)
+	private String name;
+	@Transient
+	private Integer age;
+	@Temporal(TemporalType.DATE)
+	private Date birthDate;
+	@Enumerated(EnumType.STRING)
+	private Gender gender;
+
+	public Long getId() {
+		return id;
+	}
+
+	public void setId(Long id) {
+		this.id = id;
+	}
+
+	public String getName() {
+		return name;
+	}
+
+	public void setName(String name) {
+		this.name = name;
+	}
+
+	public Integer getAge() {
+		return age;
+	}
+
+	public void setAge(Integer age) {
+		this.age = age;
+	}
+
+	public Date getBirthDate() {
+		return birthDate;
+	}
+
+	public void setBirthDate(Date birthDate) {
+		this.birthDate = birthDate;
+	}
+
+	public Gender getGender() {
+		return gender;
+	}
+
+	public void setGender(Gender gender) {
+		this.gender = gender;
+	}
+
+}

persistence-modules/java-jpa/src/main/java/com/baeldung/util/Gender.java

@@ -0,0 +1,6 @@
+package com.baeldung.util;
+
+public enum Gender {
+	MALE,
+	FEMALE
+}

persistence-modules/java-jpa/src/main/resources/META-INF/persistence.xml

@@ -147,5 +147,20 @@
             <property name="hibernate.temp.use_jdbc_metadata_defaults" value="false" />
         </properties>
     </persistence-unit>
-
+    
+    <persistence-unit name="jpa-entity-definition">
+        <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
+        <class>com.baeldung.jpa.entity.Student</class>
+        <exclude-unlisted-classes>true</exclude-unlisted-classes>
+        <properties>
+            <property name="javax.persistence.jdbc.driver" value="org.h2.Driver" />
+            <property name="javax.persistence.jdbc.url" value="jdbc:h2:mem:test" />
+            <property name="javax.persistence.jdbc.user" value="sa" />
+            <property name="javax.persistence.jdbc.password" value="" />
+            <property name="hibernate.dialect" value="org.hibernate.dialect.H2Dialect" />
+            <property name="hibernate.hbm2ddl.auto" value="create-drop" />
+            <property name="show_sql" value="true" />
+            <property name="hibernate.temp.use_jdbc_metadata_defaults" value="false" />
+        </properties>
+    </persistence-unit>
 </persistence>

persistence-modules/java-jpa/src/test/java/com/baeldung/jpa/entity/StudentEntityIntegrationTest.java

@@ -0,0 +1,91 @@
+package com.baeldung.jpa.entity;
+
+import static org.junit.Assert.assertEquals;
+
+import java.time.LocalDate;
+import java.time.ZoneId;
+import java.util.Date;
+import java.util.List;
+
+import javax.persistence.EntityManager;
+import javax.persistence.EntityManagerFactory;
+import javax.persistence.Persistence;
+import javax.persistence.TypedQuery;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import com.baeldung.util.Gender;
+
+public class StudentEntityIntegrationTest {
+
+	private EntityManagerFactory emf;
+	private EntityManager em;
+
+	@Before
+	public void setup() {
+		emf = Persistence.createEntityManagerFactory("jpa-entity-definition");
+		em = emf.createEntityManager();
+	}
+
+	@Test
+	public void persistStudentThenRetrieveTheDetails() {
+		Student student = createStudentWithRelevantDetails();
+		persist(student);
+		clearThePersistenceContext();
+		List<Student> students = getStudentsFromTable();
+		checkAssertionsWith(students);
+	}
+
+	@After
+	public void destroy() {
+		if (em != null) {
+			em.close();
+		}
+		if (emf != null) {
+			emf.close();
+		}
+	}
+
+	private void clearThePersistenceContext() {
+		em.clear();
+	}
+
+	private void checkAssertionsWith(List<Student> students) {
+		assertEquals(1, students.size());
+		Student john = students.get(0);
+		assertEquals(1L, john.getId().longValue());
+		assertEquals(null, john.getAge());
+		assertEquals("John", john.getName());
+	}
+
+	private List<Student> getStudentsFromTable() {
+		String selectQuery = "SELECT student FROM Student student";
+		TypedQuery<Student> selectFromStudentTypedQuery = em.createQuery(selectQuery, Student.class);
+		List<Student> students = selectFromStudentTypedQuery.getResultList();
+		return students;
+	}
+
+	private void persist(Student student) {
+		em.getTransaction().begin();
+		em.persist(student);
+		em.getTransaction().commit();
+	}
+
+	private Student createStudentWithRelevantDetails() {
+		Student student = new Student();
+		student.setAge(20); // the 'age' field has been annotated with @Transient
+		student.setName("John");
+		Date date = getDate();
+		student.setBirthDate(date);
+		student.setGender(Gender.MALE);
+		return student;
+	}
+
+	private Date getDate() {
+		LocalDate localDate = LocalDate.of(2008, 7, 20);
+		return Date.from(localDate.atStartOfDay(ZoneId.systemDefault()).toInstant());
+	}
+
+}