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JPA Entity Graph.

This commit is contained in:
eelhazati 2018-11-23 17:00:08 +01:00
parent 9127733ad1
commit 64bc8a412d
8 changed files with 428 additions and 19 deletions
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26
persistence-modules/java-jpa/src/main/java/com/baeldung/jpa/entitygraph/MainApp.java Normal file
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package com.baeldung.jpa.entitygraph;
import com.baeldung.jpa.entitygraph.model.Post;
import com.baeldung.jpa.entitygraph.repo.PostRepository;
public class MainApp {
public static void main(String... args) {
Long postId = 1L;
Post post = null;
PostRepository postRepository = new PostRepository();
//Using EntityManager.find().
post = postRepository.find(postId);
post = postRepository.findWithEntityGraph(postId);
post = postRepository.findWithEntityGraph2(postId);
//Using JPQL: Query and TypedQuery
post = postRepository.findUsingJpql(postId);
//Using Criteria API
post = postRepository.findUsingCriteria(postId);
postRepository.clean();
}
}

63
persistence-modules/java-jpa/src/main/java/com/baeldung/jpa/entitygraph/model/Comment.java Normal file
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package com.baeldung.jpa.entitygraph.model;
import javax.persistence.*;
@Entity
public class Comment {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String reply;
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn
private Post post;
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn
private User user;
//...
public Comment() {
}
public Comment(String reply, Post post, User user) {
this.reply = reply;
this.post = post;
this.user = user;
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getReply() {
return reply;
}
public void setReply(String reply) {
this.reply = reply;
}
public Post getPost() {
return post;
}
public void setPost(Post post) {
this.post = post;
}
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
}

86
persistence-modules/java-jpa/src/main/java/com/baeldung/jpa/entitygraph/model/Post.java Normal file
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package com.baeldung.jpa.entitygraph.model;
import javax.persistence.*;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;
@NamedEntityGraph(
name = "post-entity-graph",
attributeNodes = {
@NamedAttributeNode("subject"),
@NamedAttributeNode("user"),
@NamedAttributeNode("comments"),
}
)
@NamedEntityGraph(
name = "post-entity-graph-with-comment-users",
attributeNodes = {
@NamedAttributeNode("subject"),
@NamedAttributeNode("user"),
@NamedAttributeNode(value = "comments", subgraph = "comments-subgraph"),
},
subgraphs = {
@NamedSubgraph(
name = "comments-subgraph",
attributeNodes = {
@NamedAttributeNode("user")
}
)
}
)
@Entity
public class Post {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String subject;
@OneToMany(mappedBy = "post")
private List<Comment> comments = new ArrayList<>();
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn
private User user;
//...
public Post() {
}
public Post(String subject, User user) {
this.subject = subject;
this.user = user;
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getSubject() {
return subject;
}
public void setSubject(String subject) {
this.subject = subject;
}
public List<Comment> getComments() {
return comments;
}
public void setComments(List<Comment> comments) {
this.comments = comments;
}
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
}

48
persistence-modules/java-jpa/src/main/java/com/baeldung/jpa/entitygraph/model/User.java Normal file
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package com.baeldung.jpa.entitygraph.model;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
@Entity
public class User {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String name;
private String email;
//...
public User() {
}
public User(String email) {
this.email = email;
}
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 String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
}

93
persistence-modules/java-jpa/src/main/java/com/baeldung/jpa/entitygraph/repo/PostRepository.java Normal file
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@ -0,0 +1,93 @@
package com.baeldung.jpa.entitygraph.repo;
import com.baeldung.jpa.entitygraph.model.Post;
import javax.persistence.*;
import javax.persistence.criteria.CriteriaBuilder;
import javax.persistence.criteria.CriteriaQuery;
import javax.persistence.criteria.Root;
import java.util.HashMap;
import java.util.Map;
public class PostRepository {
private EntityManagerFactory emf = null;
public PostRepository() {
Map properties = new HashMap();
properties.put("hibernate.show_sql", "true");
properties.put("hibernate.format_sql", "true");
emf = Persistence.createEntityManagerFactory("entity-graph-pu", properties);
}
public Post find(Long id) {
EntityManager entityManager = emf.createEntityManager();
Post post = entityManager.find(Post.class, id);
entityManager.close();
return post;
}
public Post findWithEntityGraph(Long id) {
EntityManager entityManager = emf.createEntityManager();
EntityGraph entityGraph = entityManager.getEntityGraph("post-entity-graph");
Map<String, Object> properties = new HashMap<>();
properties.put("javax.persistence.fetchgraph", entityGraph);
Post post = entityManager.find(Post.class, id, properties);
entityManager.close();
return post;
}
public Post findWithEntityGraph2(Long id) {
EntityManager entityManager = emf.createEntityManager();
EntityGraph<Post> entityGraph = entityManager.createEntityGraph(Post.class);
entityGraph.addAttributeNodes("subject");
entityGraph.addAttributeNodes("user");
entityGraph.addSubgraph("comments")
.addAttributeNodes("user");
Map<String, Object> properties = new HashMap<>();
properties.put("javax.persistence.fetchgraph", entityGraph);
Post post = entityManager.find(Post.class, id, properties);
entityManager.close();
return post;
}
public Post findUsingJpql(Long id) {
EntityManager entityManager = emf.createEntityManager();
EntityGraph entityGraph = entityManager.getEntityGraph("post-entity-graph-with-comment-users");
Post post = entityManager.createQuery("Select p from Post p where p.id=:id", Post.class)
.setParameter("id", id)
.setHint("javax.persistence.fetchgraph", entityGraph)
.getSingleResult();
entityManager.close();
return post;
}
public Post findUsingCriteria(Long id) {
EntityManager entityManager = emf.createEntityManager();
EntityGraph entityGraph = entityManager.getEntityGraph("post-entity-graph-with-comment-users");
CriteriaBuilder criteriaBuilder = entityManager.getCriteriaBuilder();
CriteriaQuery<Post> criteriaQuery = criteriaBuilder.createQuery(Post.class);
Root<Post> root = criteriaQuery.from(Post.class);
criteriaQuery.where(criteriaBuilder.equal(root.<Long>get("id"), id));
TypedQuery<Post> typedQuery = entityManager.createQuery(criteriaQuery);
typedQuery.setHint("javax.persistence.loadgraph", entityGraph);
Post post = typedQuery.getSingleResult();
entityManager.close();
return post;
}
public void clean() {
emf.close();
}
}

51
persistence-modules/java-jpa/src/main/resources/META-INF/persistence.xml
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@ -9,12 +9,12 @@
<provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
<class>com.baeldung.sqlresultsetmapping.ScheduledDay</class>
<properties>
<property name="javax.persistence.jdbc.driver" value="org.h2.Driver" />
<property name="javax.persistence.jdbc.driver" value="org.h2.Driver"/>
<property name="javax.persistence.jdbc.url"
value="jdbc:h2:mem:test;INIT=RUNSCRIPT FROM 'classpath:database.sql'" />
<property name="javax.persistence.jdbc.user" value="sa" />
<property name="javax.persistence.jdbc.password" value="" />
<property name="hibernate.dialect" value="org.hibernate.dialect.H2Dialect" />
value="jdbc:h2:mem:test;INIT=RUNSCRIPT FROM 'classpath:database.sql'"/>
<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"/>
@ -25,12 +25,12 @@
<provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
<class>com.baeldung.jpa.stringcast.Message</class>
<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="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>
@ -40,12 +40,29 @@
<provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
<class>com.baeldung.jpa.model.Car</class>
<properties>
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver" />
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://127.0.0.1:3306/baeldung" />
<property name="javax.persistence.jdbc.user" value="baeldung" />
<property name="javax.persistence.jdbc.password" value="YourPassword" />
<property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect" />
<property name="hibernate.show_sql" value="true" />
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver"/>
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://127.0.0.1:3306/baeldung"/>
<property name="javax.persistence.jdbc.user" value="baeldung"/>
<property name="javax.persistence.jdbc.password" value="YourPassword"/>
<property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect"/>
<property name="hibernate.show_sql" value="true"/>
</properties>
</persistence-unit>
<persistence-unit name="entity-graph-pu" transaction-type="RESOURCE_LOCAL">
<class>com.baeldung.jpa.entitygraph.model.Post</class>
<class>com.baeldung.jpa.entitygraph.model.User</class>
<class>com.baeldung.jpa.entitygraph.model.Comment</class>
<exclude-unlisted-classes>true</exclude-unlisted-classes>
<properties>
<!--H2-->
<property name="javax.persistence.jdbc.driver" value="org.h2.Driver"/>
<property name="javax.persistence.jdbc.url"
value="jdbc:h2:mem:entitygraphdb;DB_CLOSE_DELAY=-1;DB_CLOSE_ON_EXIT=FALSE"/>
<property name="javax.persistence.schema-generation.database.action" value="drop-and-create"/>
<property name="javax.persistence.sql-load-script-source" value="data-init.sql"/>
</properties>
</persistence-unit>

8
persistence-modules/java-jpa/src/main/resources/data-init.sql Normal file
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INSERT INTO `USER` (`ID`,`NAME`,`EMAIL`) VALUES (1,'user1','user1@test.com');
INSERT INTO `USER` (`ID`,`NAME`,`EMAIL`) VALUES (2,'user2','user2@test.com');
INSERT INTO `USER` (`ID`,`NAME`,`EMAIL`) VALUES (3,'user3','user3@test.com');
INSERT INTO `POST` (`ID`,`SUBJECT`,`USER_ID`) VALUES (1,'JPA Entity Graph In Action',1);
INSERT INTO `COMMENT` (`ID`,`REPLY`,`POST_ID`,`USER_ID`) VALUES (1,'Nice !!',1,2);
INSERT INTO `COMMENT` (`ID`,`REPLY`,`POST_ID`,`USER_ID`) VALUES (2,'Cool !!',1,3);

68
persistence-modules/java-jpa/src/test/java/com/baeldung/jpa/entitygraph/repo/PostRepositoryTest.java Normal file
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package com.baeldung.jpa.entitygraph.repo;
import com.baeldung.jpa.entitygraph.model.Comment;
import com.baeldung.jpa.entitygraph.model.Post;
import com.baeldung.jpa.entitygraph.model.User;
import org.hibernate.LazyInitializationException;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.Test;
import static org.junit.Assert.*;
public class PostRepositoryTest {
private static PostRepository postRepository = null;
@BeforeClass
public static void once() {
postRepository = new PostRepository();
}
@Test(expected = LazyInitializationException.class)
public void find() {
Post post = postRepository.find(1L);
assertNotNull(post.getUser());
String email = post.getUser().getEmail();
assertNull(email);
}
@Test
public void findWithEntityGraph() {
Post post = postRepository.findWithEntityGraph(1L);
assertNotNull(post.getUser());
String email = post.getUser().getEmail();
assertNotNull(email);
}
@Test(expected = LazyInitializationException.class)
public void findWithEntityGraph_Comment_Without_User() {
Post post = postRepository.findWithEntityGraph(1L);
assertNotNull(post.getUser());
String email = post.getUser().getEmail();
assertNotNull(email);
assertNotNull(post.getComments());
assertEquals(post.getComments().size(), 2);
Comment comment = post.getComments().get(0);
assertNotNull(comment);
User user = comment.getUser();
user.getEmail();
}
@Test
public void findWithEntityGraph2_Comment_With_User() {
Post post = postRepository.findWithEntityGraph2(1L);
assertNotNull(post.getComments());
assertEquals(post.getComments().size(), 2);
Comment comment = post.getComments().get(0);
assertNotNull(comment);
User user = comment.getUser();
assertNotNull(user);
assertEquals(user.getEmail(), "user2@test.com");
}
@AfterClass
public static void destroy() {
postRepository.clean();
}
}