Step by Step Procedure for the Hello World Application:
- Install the Google Plugin
- Create a new Web application and untick GWT (Google Web Toolkit)
- Download the latest Spring Release
- Add the Jars to the folder WEB-INF/lib
The following JAR files should be present in the folder:
Make the Following Changes to the web.xml file
<?xml version="1.0" encoding="utf-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee" version="2.5">
<servlet>
<servlet-name>dispatcher</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>dispatcher</servlet-name>
<url-pattern>/a/*</url-pattern>
</servlet-mapping>
</web-app>
Create a file dispatcher-servler.xml in the WEB-INF Directory
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
<context:component-scan base-package="ipathshala.controllers" />
<bean id="viewResolver"
class="org.springframework.web.servlet.view.InternalResourceViewResolver"
p:prefix="/WEB-INF/views/" p:suffix=".jsp" >
<property name="viewClass" value="org.springframework.web.servlet.view.JstlView" />
</bean>
</beans>
HelloController.java
package ipathshala.controllers;
import javax.servlet.http.HttpServletRequest;
import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import com.google.appengine.api.users.UserService;
import com.google.appengine.api.users.UserServiceFactory;
@Controller
@RequestMapping("/hello")
public class HelloController {
private UserService userService = UserServiceFactory.getUserService();
@RequestMapping(method = RequestMethod.GET)
public String hello(HttpServletRequest request, ModelMap model)
{
String url = request.getRequestURI();
String message;
if(request.getUserPrincipal() != null)
{
message = new StringBuilder()
.append("Hello, ")
.append(request.getUserPrincipal().getName())
.append("! You can <a href=\"")
.append(userService.createLogoutURL(url))
.append("\">Sign Out</a>.").toString();
}else{
message = new StringBuilder()
.append("Please ")
.append("<a href=\"")
.append(userService.createLoginURL(url))
.append("\">Sign In</a>.").toString();
}
model.addAttribute("message", message);
return "hello/hello";
}
}
This line above @RequestMapping("/hello") maps all the requests /a/hello to this controller after being examined by the DispatcherServlet.Create a Folder views under WEB-INF and two Sub folders hello and common.
hello/hello.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ page isELIgnored="false" %>
<%@ include file="/WEB-INF/views/common/includes.jsp" %>
<p>${message}</p>
common/includes.jsp
<%@ page session="false"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ taglib prefix="fmt" uri="http://java.sun.com/jsp/jstl/fmt" %>
You should now be able to click “Debug” and run the application by visiting “localhost:8888/a/hello”.
References:
