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Refactor Eager Loading vs Lazy Loading

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This commit is contained in:
Grzegorz Piwowarek
2016-08-12 09:29:31 +02:00
parent e5c5b89755
commit 414821e5ba
6 changed files with 282 additions and 299 deletions
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141
spring-hibernate4/src/main/java/com/baeldung/hibernate/fetching/model/OrderDetail.java
View File

@@ -3,71 +3,80 @@ package com.baeldung.hibernate.fetching.model;
import java.io.Serializable;
import java.sql.Date;
public class OrderDetail implements Serializable{
public class OrderDetail implements Serializable {
private static final long serialVersionUID = 1L;
private Long orderId;
private Date orderDate;
private String orderDesc;
private User user;
public OrderDetail() {
}
public OrderDetail(Date orderDate, String orderDesc) {
super();
this.orderDate = orderDate;
this.orderDesc = orderDesc;
}
public Date getOrderDate() {
return orderDate;
}
public void setOrderDate(Date orderDate) {
this.orderDate = orderDate;
}
public String getOrderDesc() {
return orderDesc;
}
public void setOrderDesc(String orderDesc) {
this.orderDesc = orderDesc;
}
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((orderId == null) ? 0 : orderId.hashCode());
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
OrderDetail other = (OrderDetail) obj;
if (orderId == null) {
if (other.orderId != null)
return false;
} else if (!orderId.equals(other.orderId))
return false;
return true;
}
public Long getOrderId() {
return orderId;
}
public void setOrderId(Long orderId) {
this.orderId = orderId;
}
private static final long serialVersionUID = 1L;
private Long orderId;
private Date orderDate;
private String orderDesc;
private User user;
public OrderDetail(){
}
public OrderDetail(Date orderDate, String orderDesc) {
super();
this.orderDate = orderDate;
this.orderDesc = orderDesc;
}
public Date getOrderDate() {
return orderDate;
}
public void setOrderDate(Date orderDate) {
this.orderDate = orderDate;
}
public String getOrderDesc() {
return orderDesc;
}
public void setOrderDesc(String orderDesc) {
this.orderDesc = orderDesc;
}
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((orderId == null) ? 0 : orderId.hashCode());
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
OrderDetail other = (OrderDetail) obj;
if (orderId == null) {
if (other.orderId != null)
return false;
} else if (!orderId.equals(other.orderId))
return false;
return true;
}
public Long getOrderId() {
return orderId;
}
public void setOrderId(Long orderId) {
this.orderId = orderId;
}
}

80
spring-hibernate4/src/main/java/com/baeldung/hibernate/fetching/model/User.java
View File

@@ -5,92 +5,90 @@ import java.util.HashSet;
import java.util.Set;
public class User implements Serializable {
private static final long serialVersionUID = 1L;
private Long userId;
private static final long serialVersionUID = 1L;
private Long userId;
private String userName;
private String firstName;
private String lastName;
private Set<OrderDetail> orderDetail = new HashSet<OrderDetail>();
public User() {
}
public User(final Long userId, final String userName, final String firstName, final String lastName) {
super();
this.userId = userId;
this.userName = userName;
this.firstName = firstName;
this.lastName = lastName;
super();
this.userId = userId;
this.userName = userName;
this.firstName = firstName;
this.lastName = lastName;
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((userId == null) ? 0 : userId.hashCode());
return result;
final int prime = 31;
int result = 1;
result = prime * result + ((userId == null) ? 0 : userId.hashCode());
return result;
}
@Override
public boolean equals(final Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
final User other = (User) obj;
if (userId == null) {
if (other.userId != null)
return false;
} else if (!userId.equals(other.userId))
return false;
return true;
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
final User other = (User) obj;
if (userId == null) {
if (other.userId != null)
return false;
} else if (!userId.equals(other.userId))
return false;
return true;
}
public Long getUserId() {
return userId;
return userId;
}
public void setUserId(final Long userId) {
this.userId = userId;
this.userId = userId;
}
public String getUserName() {
return userName;
return userName;
}
public void setUserName(final String userName) {
this.userName = userName;
this.userName = userName;
}
public String getFirstName() {
return firstName;
return firstName;
}
public void setFirstName(final String firstName) {
this.firstName = firstName;
this.firstName = firstName;
}
public String getLastName() {
return lastName;
return lastName;
}
public void setLastName(final String lastName) {
this.lastName = lastName;
this.lastName = lastName;
}
public Set<OrderDetail> getOrderDetail() {
return orderDetail;
}
public Set<OrderDetail> getOrderDetail() {
return orderDetail;
}
public void setOrderDetail(Set<OrderDetail> orderDetail) {
this.orderDetail = orderDetail;
}
public void setOrderDetail(Set<OrderDetail> orderDetail) {
this.orderDetail = orderDetail;
}
}

43
spring-hibernate4/src/main/java/com/baeldung/hibernate/fetching/util/HibernateUtil.java
View File

@@ -1,33 +1,30 @@
package com.baeldung.hibernate.fetching.util;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
public class HibernateUtil {
private static SessionFactory factory;
@SuppressWarnings("deprecation")
public static Session getHibernateSession(String fetchMethod) {
//two config files are there
//one with lazy loading enabled
//another lazy = false
SessionFactory sf = null;
if ("lazy".equals(fetchMethod)) {
sf = new Configuration().configure("fetchingLazy.cfg.xml").buildSessionFactory();
} else {
sf = new Configuration().configure("fetching.cfg.xml").buildSessionFactory();
}
// fetching.cfg.xml is used for this example
final Session session = sf.openSession();
return session;
}
@SuppressWarnings("deprecation")
public static Session getHibernateSession(String fetchMethod) {
//two config files are there
//one with lazy loading enabled
//another lazy = false
public static Session getHibernateSession() {
SessionFactory sf = null;
sf = new Configuration().configure("fetching.cfg.xml").buildSessionFactory();
final Session session = sf.openSession();
return session;
}
final String configFileName = "lazy".equals(fetchMethod) ?
"fetchingLazy.cfg.xml" :
"fetching.cfg.xml";
return new Configuration()
.configure(configFileName)
.buildSessionFactory().openSession();
}
public static Session getHibernateSession() {
return new Configuration()
.configure("fetching.cfg.xml")
.buildSessionFactory()
.openSession();
}
}

171
spring-hibernate4/src/main/java/com/baeldung/hibernate/fetching/view/FetchingAppView.java
View File

@@ -17,97 +17,94 @@ import com.baeldung.hibernate.fetching.model.User;
public class FetchingAppView {
public FetchingAppView(){
}
//lazily loaded
public boolean lazyLoaded(){
final Session sessionLazy = HibernateUtil.getHibernateSession("lazy");
List<User> users = sessionLazy.createQuery("From User").list();
User userLazyLoaded = new User();
userLazyLoaded = users.get(3);
//since data is lazyloaded so data won't be initialized
Set<OrderDetail> orderDetailSet = userLazyLoaded.getOrderDetail();
return (Hibernate.isInitialized(orderDetailSet));
}
//eagerly loaded
public boolean eagerLoaded(){
final Session sessionEager = HibernateUtil.getHibernateSession();
//data should be loaded in the following line
//also note the queries generated
List<User> users =sessionEager.createQuery("From User").list();
User userEagerLoaded = new User();
userEagerLoaded = users.get(3);
Set<OrderDetail> orderDetailSet = userEagerLoaded.getOrderDetail();
return (Hibernate.isInitialized(orderDetailSet));
}
//creates test data
//call this method to create the data in the database
public void createTestData() {
public FetchingAppView() {
final Session session = HibernateUtil.getHibernateSession();
Transaction tx = null;
tx = session.beginTransaction();
final User user1 = new User();
final User user2 = new User();
final User user3 = new User();
user1.setFirstName("Priyam");
user1.setLastName("Banerjee");
user1.setUserName("priyambanerjee");
session.save(user1);
user2.setFirstName("Navneeta");
user2.setLastName("Mukherjee");
user2.setUserName("nmukh");
session.save(user2);
user3.setFirstName("Molly");
user3.setLastName("Banerjee");
user3.setUserName("mollyb");
session.save(user3);
}
final OrderDetail order1 = new OrderDetail();
final OrderDetail order2 = new OrderDetail();
final OrderDetail order3 = new OrderDetail();
final OrderDetail order4 = new OrderDetail();
final OrderDetail order5 = new OrderDetail();
public boolean lazyLoaded() {
final Session sessionLazy = HibernateUtil.getHibernateSession("lazy");
List<User> users = sessionLazy.createQuery("From User").list();
User userLazyLoaded = users.get(3);
//since data is lazyloaded so data won't be initialized
Set<OrderDetail> orderDetailSet = userLazyLoaded.getOrderDetail();
order1.setOrderDesc("First Order");
order1.setOrderDate(new Date(2014, 10, 12));
order1.setUser(user1);
order2.setOrderDesc("Second Order");
order2.setOrderDate(new Date(2016, 10, 25));
order2.setUser(user1);
order3.setOrderDesc("Third Order");
order3.setOrderDate(new Date(2015, 2, 17));
order3.setUser(user2);
order4.setOrderDesc("Fourth Order");
order4.setOrderDate(new Date(2014, 10, 1));
order4.setUser(user2);
order5.setOrderDesc("Fifth Order");
order5.setOrderDate(new Date(2014, 9, 11));
order5.setUser(user3);
session.saveOrUpdate(order1);
session.saveOrUpdate(order2);
session.saveOrUpdate(order3);
session.saveOrUpdate(order4);
session.saveOrUpdate(order5);
return (Hibernate.isInitialized(orderDetailSet));
}
// session.saveOrUpdate(user1);
tx.commit();
session.close();
public boolean eagerLoaded() {
final Session sessionEager = HibernateUtil.getHibernateSession();
//data should be loaded in the following line
//also note the queries generated
List<User> users = sessionEager.createQuery("From User").list();
User userEagerLoaded = users.get(3);
Set<OrderDetail> orderDetailSet = userEagerLoaded.getOrderDetail();
}
return (Hibernate.isInitialized(orderDetailSet));
}
//creates test data
//call this method to create the data in the database
public void createTestData() {
final Session session = HibernateUtil.getHibernateSession();
Transaction tx = session.beginTransaction();
final User user1 = new User();
final User user2 = new User();
final User user3 = new User();
user1.setFirstName("Priyam");
user1.setLastName("Banerjee");
user1.setUserName("priyambanerjee");
session.save(user1);
user2.setFirstName("Navneeta");
user2.setLastName("Mukherjee");
user2.setUserName("nmukh");
session.save(user2);
user3.setFirstName("Molly");
user3.setLastName("Banerjee");
user3.setUserName("mollyb");
session.save(user3);
final OrderDetail order1 = new OrderDetail();
final OrderDetail order2 = new OrderDetail();
final OrderDetail order3 = new OrderDetail();
final OrderDetail order4 = new OrderDetail();
final OrderDetail order5 = new OrderDetail();
order1.setOrderDesc("First Order");
order1.setOrderDate(new Date(2014, 10, 12));
order1.setUser(user1);
order2.setOrderDesc("Second Order");
order2.setOrderDate(new Date(2016, 10, 25));
order2.setUser(user1);
order3.setOrderDesc("Third Order");
order3.setOrderDate(new Date(2015, 2, 17));
order3.setUser(user2);
order4.setOrderDesc("Fourth Order");
order4.setOrderDate(new Date(2014, 10, 1));
order4.setUser(user2);
order5.setOrderDesc("Fifth Order");
order5.setOrderDate(new Date(2014, 9, 11));
order5.setUser(user3);
session.saveOrUpdate(order1);
session.saveOrUpdate(order2);
session.saveOrUpdate(order3);
session.saveOrUpdate(order4);
session.saveOrUpdate(order5);
// session.saveOrUpdate(user1);
tx.commit();
session.close();
}
}