Monday, 19 March 2012

spring hello world example


web.xml settings


<?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>SpringHelloWorld</display-name>
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
  
  <servlet>
<servlet-name>helloworld</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<load-on-startup>1</load-on-startup>

</servlet>

<servlet-mapping>
<servlet-name>helloworld</servlet-name>
<url-pattern>*.html</url-pattern>
</servlet-mapping>
</web-app>
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    The name of the WebApplicationContext file is determined by the value of the <servlet-name> element in the web.xml by appending '-servlet.xml'. Hence the current WebApplicationContext file name will be helloworld-servlet.xml. In this particular file you may define the spring beans.



<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">

<!-- the application context definition for the helloworld DispatcherServlet -->
<bean id="viewResolver"
class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="viewClass"
value="org.springframework.web.servlet.view.JstlView" />
<property name="prefix" value="/jsp/" />
<property name="suffix" value=".jsp"></property>
</bean>

<bean name="/hello.html" class="com.prajith.helloworld.HelloController"/>
</beans>

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   index.jsp :default page to be loaded when the application is started but we will be redirecting it to get the hello.jsp page using spring mvc framework.





<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<c:redirect url="/hello.html" />
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>

</body>
</html>



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hello.jsp : the view of the application where the hello world message will be displayed.





<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Hello World</title>
</head>
<body>

<h1>Hello - Spring Application</h1>
<p>
Greetings, it is now
<c:out value="${now}" />
</p>

</body>
</html>







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HelloController.java : we will be utilizing this controller to redirect to the hello.jsp view.






package com.prajith.helloworld;

import java.io.IOException;
import java.util.Date;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.web.servlet.ModelAndView;

import org.springframework.web.servlet.mvc.Controller;


public class HelloController implements Controller {
protected final Log logger= LogFactory.getLog(getClass());

public ModelAndView handleRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String now= (new Date()).toString();
logger.info("Returning hello view with "+now);
return new ModelAndView("hello","now",now);
}
}

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Required Jars:

1. commons-logging.jar
2. jstl.jar
3. spring-webmvc.jar
4. spring.jar
5. standard.jar

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Project Structure

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