strut2-spring-hibernate

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Workshop Agenda

Day 1

1.Understanding Struts2 2.Architecture of Struts2

3.Features of Struts2

4.Environment Setup

5.Understanding Configuration of Project

Day 1 Continue

6.Practical Lab

7.Introduction to Hibernate

8.Demo of Struts2 Application

Understanding Struts2

•Apache Struts 2 is an elegant, extensible framework for creating enterprise-ready Java web applications.

•The framework is designed to streamline the full development cycle, from building, to deploying, to maintaining applications over time.

•To make web development easier for the developers.

MVC Design Pattern

Architecture of Struts2

What kind of MVC is Struts2

Struts 2 is pull MVC

Request Life Cycle

• User sends a request to the server for requesting for some resource (i.e pages).

• The FilterDispatcher looks at the request and then determines the appropriate Action.

• Configured interceptors functionalities applies such as validation, file upload etc.

• Selected action is executed to perform the requested operation.

• Again, configured interceptors are applied to do any post-processing if required.

• Finally the result is prepared by the view and returns the result to the user.

Features of Struts2

• POJO forms and POJO actions

• Tag Support

• AJAX Support

• Easy Integration

Features continued…

• Template Support

• Plugin Support

• Profiling

• Easy to modify tags

• Promote less configuration

• View Technologies (JSP, Velocity, Freemarker,etc)

Environment Setup

4 Simple Steps:

•Step 1 - Setup Java Development Kit (JDK)

•Step 2 - Setup Apache Tomcat

•Step 3 - Setup Eclipse (IDE)

•Step 4 - Setup Struts2 Libraries

Understand Configuring Project 4 Simple Steps

•Create an Action Class

•Create a View

•Create a launch page

•Now configure all of them

Create an Action Classpublic class Student{ private String fullName;

public String execute() throws Exception { return "success"; } public String getFullName() { return name; }

public void setFullName(String name) { this.name = name; }}

Create View

<%@ page contentType="text/html; charset=UTF-8" %><%@ taglib prefix="s" uri="/struts-tags" %><html><head><title>Welcome to Team Go Getters</title></head><body> Hello, We are glad to have <s:property value=”fullName"/> as our student.</body></html>

Create a launch page<%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%><%@ taglib prefix="s" uri="/struts-tags"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><title>Struts2 Workshop</title></head><body> <h1>Welcome to Team Go Getters</h1> <form action=”welcome"> <label for="name">Please enter your name</label><br/> <input type="text" name=”fullName"/> <input type="submit" value=”Enroll"/> </form></body></html>

Configuration Files

Struts.xml file

•Mapping between URL ,Action classes and Result Types (View)

•Since Struts 2 requires struts.xml to be present in classes folder.

• So create struts.xml file under the WebContent/WEB-INF/classes folder.

Struts.xml

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN" "http://struts.apache.org/dtds/struts-2.0.dtd"><struts><constant name="struts.devMode" value="true" /> <package name=”workshop" extends="struts-default"> <action name=”welcome" class="com.teamgogetters.struts2.Employee" method="execute"> <result name="success">/Welcome.jsp</result> </action> </package></struts>

Multiple struts.xml files

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN" "http://struts.apache.org/dtds/struts-2.0.dtd"><struts> <include file="my-struts1.xml"/> <include file="my-struts2.xml"/></struts>

Web.xml

• Entry point for any request to Struts 2

• Mapping FilterDispatcher

• Deployment Descriptor

• Security Parameters

Web.xml<?xml version="1.0" encoding="UTF-8"?><web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0"> <display-name>Struts 2</display-name> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list> <filter> <filter-name>struts2</filter-name> <filter-class> org.apache.struts2.dispatcher.FilterDispatcher </filter-class> </filter>

<filter-mapping> <filter-name>struts2</filter-name> <url-pattern>/*</url-pattern> </filter-mapping></web-app>

Interceptors

• Providing preprocessing logic before the action is called.

• Providing post-processing logic after the action is called.

• Catching exceptions so that alternate processing can be performed.

List of Interceptors

• timer• params• checkbox• createSession• logger• fileUpload• scope• alias

Snippet<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN" "http://struts.apache.org/dtds/struts-2.0.dtd"><struts> <constant name="struts.devMode" value="true" /> <package name=”workshop" extends="struts-default"> <action name=”welcome" class="com.teamgogetters.struts2.Employee" method="execute"> <interceptor-ref name="params"/> <interceptor-ref name="timer" /> <result name="success">/welcome.jsp</result> </action> </package></struts>

Result and Result Types

• <results> tag plays the role of a view in the Struts2 MVC framework. The action is responsible for executing the business logic. The next step after executing the business logic is to display the view using the <results> tag.

• Struts comes with a number of predefined result types and whatever we've already seen that was the default result type dispatcher, which is used to dispatch to JSP pages. Struts allow you to use other markup languages for the view technology to present the results and popular choices include Velocity, Freemaker, XSLT and Tiles.

Snippet

<result name="success" type="dispatcher"> <param name="location"> /HelloWorld.jsp </param ></result>

<result name="success" type="freemarker"> <param name="location"> /hello.fm </param></result>

<result name="success" type="freemarker"> <param name="location"> /hello.fm </param></result>

Practical Lab

JDBC is going obsolete?

• Complex if it is used in large projects

• Large programming overhead

• No encapsulation

• Hard to implement MVC concept

• Query is DBMS specific

What’s Next ?

Hibernate: ORM

• Hibernate is a high-performance Object/Relational persistence and query service

• Hibernate takes care of the mapping from Java classes to database tables

• Hibernate data query and retrieval facilities

ORM New Generation

1. Let business code access objects rather than DB tables.

2. Hides details of SQL queries from OO logic.

3. Based on JDBC 'under the hood’

4. No need to deal with the database implementation.

ORM New Generation…

5. Entities based on business concepts rather than database structure.

6. Transaction management and automatic key generation.

7. Fast development of application.

Visual presentation of Hibernate

Hold your breathe till tomorrow

strut2-spring-hibernate

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