{"id":65938,"date":"2021-07-18T04:10:04","date_gmt":"2021-07-18T08:10:04","guid":{"rendered":"http:\/\/bangla.salearningschool.com\/recent-posts\/ejb-3-entity-bean-basic-java-short-notes\/"},"modified":"2021-07-18T04:10:04","modified_gmt":"2021-07-18T08:10:04","slug":"ejb-3-entity-bean-basic-java-short-notes","status":"publish","type":"post","link":"http:\/\/bangla.sitestree.com\/?p=65938","title":{"rendered":"EJB 3: Entity Bean Basic #Java Short Notes"},"content":{"rendered":"<p><pre style='font-size:15px;padding-left:5px'>Plain Java objects with persistence storage. They are not remotable and must be accessed through the new javax.persistence.EntityManager service. An entity bean implementation is provided in the following three files\/classesBeansOrder.javaLineItem.javaEntity ManagerShoppingCartBean.java\/\/Order.javaimport javax.persistence.CascadeType;import javax.persistence.Entity;import javax.persistence.FetchType;import javax.persistence.GeneratedValue; import javax.persistence.GenerationType;import javax.persistence.Id;import javax.persistence.OneToMany;import javax.persistence.Table;import javax.persistence.Id;import javax.persistence.CascadeType;import javax.persistence.FetchType;import java.util.ArrayList;import java.util.Collection;@Entity@Table(name = \"PURCHASE_ORDER\")public class Order implements java.io.Serializable{   private int id;   private double total;   private Collection lineItems;   @Id @GeneratedValue(strategy=GenerationType.AUTO)   public int getId()   {      return id;   }   public void setId(int id)   {      this.id = id;   }   public double getTotal()   {      return total;   }   public void setTotal(double total)   {      this.total = total;   }   public void addPurchase(String product, int quantity, \tdouble price)   {      if (lineItems == null) lineItems = new ArrayList();      LineItem item = new LineItem();      item.setOrder(this);      item.setProduct(product);      item.setQuantity(quantity);      item.setSubtotal(quantity * price);      lineItems.add(item);      total += quantity * price;   }   @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.EAGER, \tmappedBy=\"order\")   public Collection getLineItems()   {      return lineItems;   }   public void setLineItems(Collection lineItems)   {      this.lineItems = lineItems;   }}\/\/LineItem.javaimport javax.persistence.Entity;import javax.persistence.GeneratedValue; import javax.persistence.GenerationType;import javax.persistence.Id;import javax.persistence.JoinColumn;import javax.persistence.ManyToOne;import javax.persistence.Entity;@Entitypublic class LineItem implements java.io.Serializable{   private int id;   private double subtotal;   private int quantity;   private String product;   private Order order;   @Id @GeneratedValue(strategy=GenerationType.AUTO)   public int getId()   {      return id;   }   public void setId(int id)   {      this.id = id;   }   public double getSubtotal()   {      return subtotal;   }   public void setSubtotal(double subtotal)   {      this.subtotal = subtotal;   }   public int getQuantity()   {      return quantity;   }   public void setQuantity(int quantity)   {      this.quantity = quantity;   }   public String getProduct()   {      return product;   }   public void setProduct(String product)   {      this.product = product;   }   @ManyToOne   @JoinColumn(name = \"order_id\")   public Order getOrder()   {      return order;   }   public void setOrder(Order order)   {      this.order = order;   }}\/\/ShoppingCartBean.javaInteracts with Order as a plain Java object. The checkout() method stores orders with persistence storage by using the required EntityManager service.import javax.ejb.Remote;import javax.ejb.Remove;import javax.ejb.Stateful;import javax.persistence.EntityManager;import javax.persistence.PersistenceContext;import javax.persistence.PersistenceContext;@Stateful@Remote(ShoppingCart.class)public class ShoppingCartBean implements ShoppingCart, \tjava.io.Serializable{   @PersistenceContext   private EntityManager manager;   private Order order;   public void buy(String product, int quantity, double price)   {      if (order == null) order = new Order();      order.addPurchase(product, quantity, price);   }   public Order getOrder()   {      return order;   }   @Remove   public void checkout()   {      manager.persist(order);   }} GNU Distribution Without Warranty License<\/pre>\n<\/p>\n<p> From: http:\/\/sitestree.com\/?p=4834<br \/> Categories:Java Short Notes<br \/>Tags:<br \/> Post Data:2011-12-03 23:27:24<\/p>\n<p>\t\tShop Online: <a href='https:\/\/www.ShopForSoul.com\/' target='new' rel=\"noopener\">https:\/\/www.ShopForSoul.com\/<\/a><br \/>\n\t\t(Big Data, Cloud, Security, Machine Learning): Courses: <a href='http:\/\/Training.SitesTree.com' target='new' rel=\"noopener\"> http:\/\/Training.SitesTree.com<\/a><br \/>\n\t\tIn Bengali: <a href='http:\/\/Bangla.SaLearningSchool.com' target='new' rel=\"noopener\">http:\/\/Bangla.SaLearningSchool.com<\/a><br \/>\n\t\t<a href='http:\/\/SitesTree.com' target='new' rel=\"noopener\">http:\/\/SitesTree.com<\/a><br \/>\n\t\t8112223 Canada Inc.\/JustEtc: <a href='http:\/\/JustEtc.net' target='new' rel=\"noopener\">http:\/\/JustEtc.net (Software\/Web\/Mobile\/Big-Data\/Machine Learning) <\/a><br \/>\n\t\tShop Online: <a href='https:\/\/www.ShopForSoul.com'> https:\/\/www.ShopForSoul.com\/<\/a><br \/>\n\t\tMedium: <a href='https:\/\/medium.com\/@SayedAhmedCanada' target='new' rel=\"noopener\"> https:\/\/medium.com\/@SayedAhmedCanada <\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Plain Java objects with persistence storage. They are not remotable and must be accessed through the new javax.persistence.EntityManager service. An entity bean implementation is provided in the following three files\/classesBeansOrder.javaLineItem.javaEntity ManagerShoppingCartBean.java\/\/Order.javaimport javax.persistence.CascadeType;import javax.persistence.Entity;import javax.persistence.FetchType;import javax.persistence.GeneratedValue; import javax.persistence.GenerationType;import javax.persistence.Id;import javax.persistence.OneToMany;import javax.persistence.Table;import javax.persistence.Id;import javax.persistence.CascadeType;import javax.persistence.FetchType;import java.util.ArrayList;import java.util.Collection;@Entity@Table(name = &#8220;PURCHASE_ORDER&#8221;)public class Order implements java.io.Serializable{ private int id; private &hellip; <\/p>\n<p><a class=\"more-link btn\" href=\"http:\/\/bangla.sitestree.com\/?p=65938\">Continue reading<\/a><\/p>\n","protected":false},"author":8,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[1917],"tags":[],"class_list":["post-65938","post","type-post","status-publish","format-standard","hentry","category-fromsitestree-com","item-wrap"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack-related-posts":[{"id":7003,"url":"http:\/\/bangla.sitestree.com\/?p=7003","url_meta":{"origin":65938,"position":0},"title":"MongoDB Java","author":"Author-Check- Article-or-Video","date":"March 16, 2015","format":false,"excerpt":"Done By Raju(DU) MongoDB Java Installation \u09aa\u09a6\u09cd\u09a7\u09a4\u09bf\u0983 Java program \u098f MongoDB \u09ac\u09cd\u09af\u09be\u09ac\u09b9\u09be\u09b0 \u0995\u09b0\u09be\u09b0 \u09aa\u09c2\u09b0\u09cd\u09ac\u09c7 \u0986\u09ae\u09be\u09a6\u09c7\u09b0\u0995\u09c7 \u09a8\u09bf\u09b6\u09cd\u099a\u09bf\u09a4 \u0995\u09b0\u09a4\u09c7 \u09b9\u09ac\u09c7 \u09af\u09c7 MongoDB JDBC Driver \u098f\u09ac\u0982 Java \u0986\u09ae\u09be\u09a6\u09c7\u09b0 machine \u098f \u09aa\u09c2\u09b0\u09cd\u09ac\u09c7 \u09a5\u09c7\u0995\u09c7\u0987 \u09b0\u09df\u09c7\u099b\u09c7\u0964 \u0986\u09aa\u09a8\u09bf \u0986\u09b0\u0993 Java tutorial \u09a6\u09c7\u0996\u09a4\u09c7 \u09aa\u09be\u09b0\u09c7\u09a8 \u0986\u09aa\u09a8\u09be\u09b0 machine \u098f Java installation \u0995\u09b0\u09be\u09b0 \u099c\u09a8\u09cd\u09af\u0964 \u098f\u0996\u09a8 \u09a6\u09c7\u0996\u09ac\u09c7 \u0995\u09bf\u09ad\u09be\u09ac\u09c7 MongoDB JDBC driver \u099f\u09bf\u2026","rel":"","context":"In &quot;\u09ae\u0999\u09cd\u0997 \u09a1\u09bf \u09ac\u09bf \u0964 MongoDB&quot;","block_context":{"text":"\u09ae\u0999\u09cd\u0997 \u09a1\u09bf \u09ac\u09bf \u0964 MongoDB","link":"http:\/\/bangla.sitestree.com\/?cat=222"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":10473,"url":"http:\/\/bangla.sitestree.com\/?p=10473","url_meta":{"origin":65938,"position":1},"title":"IfTag.java, IfConditionTag.java, IfThenTag.java, and IfElseTag.java, Custom tags that make use of tag nesting","author":"","date":"August 28, 2015","format":false,"excerpt":"IfTag.java, IfConditionTag.java, IfThenTag.java, and IfElseTag.java, Custom tags that make use of tag nesting IfTag.java package cwp.tags; import javax.servlet.jsp.*; import javax.servlet.jsp.tagext.*; import java.io.*; import javax.servlet.*; \/** A tag that acts like an if\/then\/else. \u00a0*\u00a0 <P> \u00a0*\u00a0 Taken from Core Web Programming Java 2 Edition \u00a0*\u00a0 from Prentice Hall and Sun Microsystems\u2026","rel":"","context":"In &quot;Code . 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