I'm currently working on a school project. We have to do a small market website in Java.
I've a small problem. I have an Index.jsp where i want to include a servlet (RandomArticle.jsp). This servlet have a .jsp and a .java and just shuffle a collection and return names.
When I display index.jsp, the html of RandomArticle.jsp is well displayed (so the include is correct) but the returned name are "null".
Here is some code:
Index.jsp (in WebContent of eclipse)
<%# page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Market</title>
</head>
<body>
<header>
<h1>market 2013</h1>
<h2>Bievenue </h2>
</header>
<nav>
<% String include = "/WEB-INF/RandomArticle.jsp"; %>
<jsp:include page='<%=include%>' />
</nav>
</body>
</html>
RandomArticle.jsp (in WEB-INF):
<h1>Liste des produits EpiMarket</h1>
<%
String productName1 = (String) request.getAttribute("productName1");
String productName2 = (String) request.getAttribute("productName2");
String productName3 = (String) request.getAttribute("productName3");
%>
<p>Acheter <% out.println(productName1); %></p>
<p>Acheter <% out.println(productName2); %></p>
<p>Acheter <% out.println(productName3); %></p>
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" 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>Market</display-name>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
<servlet>
<servlet-name>Test</servlet-name>
<servlet-class>fr.market.servlets.Test</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>Test</servlet-name>
<url-pattern>/test</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>RandomArticle</servlet-name>
<servlet-class>fr.market.servlets.RandomArticle</servlet-class>
</servlet>
</web-app>
and RandomARticle.java
public class RandomArticle extends HttpServlet {
private ArrayList<Object> allProducts;
public String getProductName(int index){
return (((AbstractProduct) allProducts.get(index)).getName());
}
public void doGet( HttpServletRequest request, HttpServletResponse response ) throws ServletException, IOException{
ADAO<AbstractProduct> dao = new DAOProduit();
allProducts = ((DAOProduit) dao).getAll();
Collections.shuffle(allProducts);
request.setAttribute("productName1", getProductName(0));
request.setAttribute("productName2", getProductName(1));
request.setAttribute("productName3", getProductName(2));
this.getServletContext().getRequestDispatcher( "/WEB-INF/RandomArticle.jsp" ).forward( request, response );
}
}
I think that the .java is never called, but I don't understand why.
Thanks for your time.
Gilles
Related
Problem: When I invoke url (url-mapping) directly in the browser it works pretty well but when I use post method to invoke servlet from jsp file, it does not work but gives an error:
Type Status Report
Message /HelloWorld/myservlet
Description The origin server did not find a current representation
for the target resource or is not willing to disclose that one exists.
Jsp page:
<%# page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="ISO-8859-1">
<title>Hello World</title>
</head>
<body>
<form method="post" action="myservlet">
<input type="submit" value ="send">
</form>
</body>
</html>
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/javaeehttp://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
id="WebApp_ID" version="3.0">
<display-name>helloworld2</display-name>
<servlet>
<servlet-name>myservlet</servlet-name>
<servlet-class>apress.helloworld.HelloWorld</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>myservlet</servlet-name>
<url-pattern>/hello</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
Servlet code:
package apress.helloworld;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class HelloWorld extends HttpServlet{
protected void doGet(HttpServletRequest request, HttpServletResponse response)
{
//System.out.println("Get Method Called");
try { response.setContentType("text/html");
`enter code here` PrintWriter printwriter = response.getWriter();
printwriter.println("<h2>");
printwriter.println("Hello World");
printwriter.println("</h2>");
}
catch
(IOException ex)
{ ex.printStackTrace(); }
}
#Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
// TODO Auto-generated method stub
try { resp.setContentType("text/html");
PrintWriter printwriter = resp.getWriter();
printwriter.println("<h2>");
printwriter.println("Hello World");
printwriter.println("</h2>");
}
catch
(IOException ex)
{ ex.printStackTrace(); }
}
}
<%# page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="ISO-8859-1">
<title>Hello World</title>
</head>
<body>
<form method="post" action="hello">
<input type="submit" value ="send">
</form>
</body>
</html>
use Above code
in HTML form action="url-mapping" you have to mention url pattern of servlet not servlet name refer your web.xml
I am learning Java CRUD Operation . I am trying to insert ,update and delete records from sql database.The insert and displaying all records methods is working but the problem is when I click edit and delete links ,its throw http 404 not found exception
Here is my HTML code display all the records .
<%#page contentType="text/html" pageEncoding="UTF-8"%>
<%#taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>All Posts</title>
</head>
<body>
<div style="width: 1200px; margin-left: auto; margin-right: auto;">
<table cellpadding="10">
<tr>
<th>Id</th>
<th>Title</th>
<th>Description</th>
<th>Detail</th>
<th>Category</th>
<th>Date</th>
<th>Image</th>
<th></th>
</tr>
<c:forEach items="${AllPost}" var="p">
<tr>
<td>${p.id}</td>
<td>${p.title}...</td>
<td>${p.description}...</td>
<td>${p.detail}...</td>
<td>${p.category}</td>
<td>${p.date}...</td>
<td>${p.image}...</td>
<td>
Edit
Delete
</td>
</tr>
</c:forEach>
</table>
</div>
</body>
</html>
Here is the HTML for EidtPost.jsp
<%#page contentType="text/html" pageEncoding="UTF-8"%>
<%#taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Edit</title>
</head>
<body>
<h1>Edit News</h1>
<div style="width: 900px; margin-left: auto; margin-right: auto">
<c:forEach items="${getNewsById}" var="p">
<form action="JSP/ManagerEditPost.jsp" method="post">
<input type="hidden" name="id" value="${p.id}">
Title:<br>
<input type="text" value="${p.title}" name="title" style="width: 200px"><br>
Description:<br>
<input type="text" value="${p.description}" name="description" style="width: 200px"><br>
Detail:<br>
<textarea name="detail" style="width: 400px; height: 200px">${p.detail}</textarea><br>
Category:
<select name="category">
<option value="${p.category}">${p.category}</option>
<option value="World">World</option>
<option value="Tech">Tech</option>
<option value="Sport">Sport</option>
</select><br>
Image:<br>
<input type="text" value="${p.image}" name="image" style="width: 200px"><br>
<input type="submit" value="Submit">
</form>
</c:forEach>
</div>
</body>
</html>
Here is the Data Access code for CRUD operation.
public void edit(int id, String title, String description, String detail, String category, String image){
try {
String sql = "update News SET title = ?, description = ?, detail = ?, category = ?, image = ?" + " where id = ?";
PreparedStatement ps= DBUtils.getPreparedStatement(sql);
ps.setString(1, title);
ps.setString(2, description);
ps.setString(3, detail);
ps.setString(4, category);
ps.setString(5, image);
ps.setInt(6, id);
ps.executeUpdate();
} catch (ClassNotFoundException | SQLException ex) {
Logger.getLogger(DataAccess.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
Here is the servlet code .
#WebServlet(name = "EditPost", urlPatterns = {"/EditPost"})
public class EditPost extends HttpServlet {
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
{
String idTemp = request.getParameter("id");
int id = Integer.parseInt(idTemp);
request.setAttribute("getNewsById", DataAccess.getNewById(id));
RequestDispatcher rd = request.getRequestDispatcher("CRUD/EditPost.jsp");
try {
rd.forward(request, response);
} catch (ServletException | IOException ex) {
Logger.getLogger(EditPost.class.getName()).log(Level.SEVERE, null, ex);
}
}
Here is the code web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.1" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd">
<context-param>
<param-name>javax.faces.PROJECT_STAGE</param-name>
<param-value>Development</param-value>
</context-param>
<servlet>
<servlet-name>Faces Servlet</servlet-name>
<servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet>
<servlet-name>EditPost</servlet-name>
<servlet-class>servlet.EditPost</servlet-class>
</servlet>
<servlet>
<servlet-name>DeletePost</servlet-name>
<servlet-class>servlet.DeletePost</servlet-class>
</servlet>
<servlet>
<servlet-name>AllPost</servlet-name>
<servlet-class>servlet.AllPost</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>Faces Servlet</servlet-name>
<url-pattern>/faces/*</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>EditPost</servlet-name>
<url-pattern>/EditPost</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>DeletePost</servlet-name>
<url-pattern>/DeletePost</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>AllPost</servlet-name>
<url-pattern>/AllPost</url-pattern>
</servlet-mapping>
<session-config>
<session-timeout>
30
</session-timeout>
</session-config>
<welcome-file-list>
<welcome-file>faces/index.xhtml</welcome-file>
</welcome-file-list>
</web-app>
Here is the screen shot of the error when i click the edit and delete link .
The following shows the minimum necessary to create the desired functionality. Obviously everything about the true implementation needs to be added.
Ultimately, the path in the .jsp needs to match to the #WebServlet path. Though the specific forwarding depends a bit on absolute vs. relative URLs.
This works in tomcat 9.0, but is likely applicable to other such servers such as glassfish, etc.
web.xml
This provides the basic information.
<web-app>
<welcome-file-list>
<welcome-file>welcome.jsp</welcome-file>
</welcome-file-list>
</web-app>
welcome.jsp
This is just an example .jsp that provides an href.
<%# page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<h1>Hello World!</h1>
<!-- note this can also be ./EditPost -->
<!-- also note that not passing any query here -->
Edit Post
</body>
</html>
EditPost.java
This is a quick example of an annotated servlet.
#WebServlet("/EditPost")
public class EditPost extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* Default constructor.
*/
public EditPost() {
}
/**
* #see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.getWriter().append("Served at: ").append(request.getContextPath());
}
/**
* #see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}
This question already has answers here:
Servlet returns "HTTP Status 404 The requested resource (/servlet) is not available"
(19 answers)
Closed 6 years ago.
I'm trying to build a twitter search using jsp, servlet, Tomcat-6.0.43 and eclipse and getting HTTP Status 404 error. Can anyone please check where am I going wrong.
My Code:
first.jsp:
<%# page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!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>Insert title here</title>
</head>
<body>
<form action="ServletValues.java" method="get">
Enter Twitter Search Details : <input type="text" name="first"><br>
<input type="submit">
</form>
</body>
</html>
TwitterServlet.java:
import java.io.IOException;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import twitter4j.Status;
import twitter4j.Twitter;
import twitter4j.TwitterException;
import twitter4j.TwitterFactory;
import twitter4j.auth.AccessToken;
public class TwitterServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public TwitterServlet() {
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String CONSUMER_KEY = "[data]";
String CONSUMER_KEY_SECRET = "[data]";
String AccessToken = "[data]";
String AccessTokenSecret = "[data]";
response.setContentType("text/html");
String input1 = request.getParameter("first");
try{
Twitter twitter = new TwitterFactory().getInstance();
twitter.setOAuthConsumer(CONSUMER_KEY, CONSUMER_KEY_SECRET);
AccessToken oathAccessToken = new AccessToken(AccessToken, AccessTokenSecret);
twitter.setOAuthAccessToken(oathAccessToken);
List<Status> status = twitter.getUserTimeline(input1);
for (Status status2 : status)
{
System.out.println("---Tweet---"+status2.getText());
}}catch (TwitterException te){
System.out.println("Error occured "+te);
}
super.doPost(request, response);
}
}
web.xml:
<?xml version="1.0" encoding="UTF-8"?>
<web-app id="WebApp_ID" version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<display-name>
Twitter12</display-name>
<servlet>
<description>
</description>
<display-name>
TwitterServlet</display-name>
<servlet-name>TwitterServlet</servlet-name>
<servlet-class>
TwitterServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>TwitterServlet</servlet-name>
<url-pattern>/TwitterServlet</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.htm</welcome-file>
<welcome-file>index.jsp</welcome-file>
<welcome-file>default.html</welcome-file>
<welcome-file>default.htm</welcome-file>
<welcome-file>default.jsp</welcome-file>
</welcome-file-list>
</web-app>
Error: HTTP Status 404 - /Twitter12/ServletValues.java
type Status report
message /Twitter12/ServletValues.java
description The requested resource is not available.
In your jsp file form action, Replace
<form action="ServletValues.java" method="get">
With
<form action="TwitterServlet" method="get">
Since in your web.xml your servlet mapping pattern is TwitterServlet for the Servlet class that you intend to call.
Also in your servlet you are just printing to System.out while you should write into the reponse stream using
response.getOutputStream().write("---Tweet---"+status2.getText());
so that it shows up in the response
Change your form action to:
<form action="/TwitterServlet" method="get">
your servlet url is /TwitterServlet as you have defined
<servlet-mapping>
<servlet-name>TwitterServlet</servlet-name>
<url-pattern>/TwitterServlet</url-pattern>
</servlet-mapping>
I'm following "Struts 2 in Action" book and under the first chapter of that book, there is a sample basic application to be developed. I tried to follow it and the action class is not calling properly. But I can view the success result JSP page. When I use the debug mode and try to debug the execute method of the action class, it is not calling. I'm using struts-2.3.15.1 libraries to develop this application.
My Action class is below :
package manning.chapterTwo;
import org.apache.struts2.config.Result;
import com.opensymphony.xwork2.ActionSupport;
#Result(name="SUCCESS", value="/chapterTwo/HelloWorld.jsp" )
public class AnnotatedHelloWorldAction extends ActionSupport{
private static final long serialVersionUID = 1L;
private static final String GREETING = "Hello ";
public String execute() {
setCustomGreeting( GREETING + getName() );
return "SUCCESS";
}
private String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
private String customGreeting;
public String getCustomGreeting()
{
return customGreeting;
}
public void setCustomGreeting( String customGreeting ){
this.customGreeting = customGreeting;
}
}
JSP Page to get the Input looks like below (NameCollector.jsp) :
<%# page contentType="text/html; charset=UTF-8" %>
<%# taglib prefix="s" uri="/struts-tags" %>
<html>
<head>
<title>Name Collector</title>
</head>
<body>
<hr>
<h4>Enter your name so that we can customize a greeting just for you!</h4>
<s:form action="annotatedHelloWorld">
<s:textfield name="name" label="Your name"/>
<s:submit/>
</s:form>
<hr>
</body>
</html>
Output JSP :
<%# page contentType="text/html; charset=UTF-8" %>
<%# taglib prefix="s" uri="/struts-tags" %>
<html>
<head>
<title>HelloWorld</title>
</head>
<body>
<hr>
<h3>Custom Greeting Page</h3>
<h4><s:property value="customGreeting"/></h4>
<hr>
</body>
</html>
web.xml file :
<?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" 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>Struts2HelloWorldXML</display-name>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.htm</welcome-file>
<welcome-file>index.jsp</welcome-file>
<welcome-file>default.html</welcome-file>
<welcome-file>default.htm</welcome-file>
<welcome-file>default.jsp</welcome-file>
</welcome-file-list>
<filter>
<filter-name>struts2</filter-name>
<filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>
<init-param>
<param-name>actionPackages</param-name>
<param-value>manning</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>struts2</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
</web-app>
How to resolve it?
You should add an action annotation to the action class or method
#ParentPackage("chapterTwo");
#Action(value="HelloWorld", results=#Result(name="SUCCESS", value="/chapterTwo/HelloWorld.jsp" ))
public class AnnotatedHelloWorldAction extends ActionSupport {
Supposed the author either using conventions to map your action or added the action annotation in the errata. Also added the parent package annotation to which the action belongs to. And don't forget to add struts2-convention-plugin to the library set, because it's missed in the examples.
I have a simple JSP project, which has 3 classes, controllers and DAO's
I can Login but when I click on my buttons, I just can't get the Parameters from the form.
Lemme show the code, and maybe You'll figure it out:
package school.controller;
import java.io.IOException;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import school.dao.StudentDAO;
import school.model.Student;
public class StudentController extends HttpServlet {
private static final long serialVersionUID = 1L;
private static String UPDATE = "/student.jsp";
private static String VIEW_COURSES = "CourseController";
private static String VIEW_GRADES = "GradeController";
private StudentDAO dao;
public StudentController() {
dao = new StudentDAO();
}
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
String forward = "";
String action = request.getParameter("name");
if (action.equalsIgnoreCase("update")) {
forward = UPDATE;
Student student = (Student) request.getAttribute("student");
request.setAttribute("student", student);
} else if (action.equalsIgnoreCase("viewgrades")) {
forward = VIEW_GRADES;
Student student = (Student) request.getAttribute("student");
request.setAttribute("student", student);
} else if (action.equalsIgnoreCase("viewcourses")) {
forward = VIEW_COURSES;
Student student = (Student) request.getAttribute("student");
request.setAttribute("student", student);
}
RequestDispatcher view = request.getRequestDispatcher(forward);
view.forward(request, response);
}
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}
And here's the 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>School_JSP</display-name>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
<servlet>
<description></description>
<display-name>CourseController</display-name>
<servlet-name>CourseController</servlet-name>
<servlet-class>school.controller.CourseController</servlet-class>
</servlet>
<servlet>
<description></description>
<display-name>StudentController</display-name>
<servlet-name>StudentController</servlet-name>
<servlet-class>school.controller.StudentController</servlet-class>
</servlet>
<servlet>
<description></description>
<display-name>LoginServlet</display-name>
<servlet-name>LoginServlet</servlet-name>
<servlet-class>school.controller.LoginServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>StudentController</servlet-name>
<url-pattern>/StudentController</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>CourseController</servlet-name>
<url-pattern>/CourseController</url-pattern>
</servlet-mapping>
</web-app>
And the mainPage.jsp
<%# 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>Main Page</title>
</head>
<body>
<h3>
Welcome,
<c:out value="${student.firstName}" />
</br>
<h1>My Personal Information</h1>
<center>
<form method="POST" action='StudentController' name="viewgrades">
<input type="submit" value="View My Grades" />
</form>
<form method="POST" action='StudentController' name="viewcourses">
<input type="submit" id="hidden" value="View My Courses" />
</form>
<form method="POST" action='StudentController' name="update">
<input type="submit" id="hidden" value="Update Personal Information" />
</form>
</center>
</h3>
</body>
</html>
You're confusing attributes and parameters.
Parameters are String values sent by the browser. They're accessed using the getParameterXxx() family of methods.
Attributes are data that you can add to a request (or session, or servlet context), or any type, in order to get them backlater. You typically add an attribute to the request in a servlet (for example, the information about the logged in user) in order to get back this attribute in the JSP and display the information.
In your code, the only place where you get a parameter is commented out. And you're trying to get a parameter named "hidden", although none of the form has an input field with than name. It's the name attribute of an input field that is submitted by the browser, and not its id attribute.
Also, you should use GET rather than POST for actions which consist in getting or reading things.
The reason you don't get any values is that the attribute "name" in the form, indeed is just the name of the form and isn't sent at all.
To actually send data, you need to provide some in the innerHTML of the form. Like this (not the best solution, but should you get running):
<form method="GET" action="StudentController" name="formName">
<input type="hidden" name="viewgrades" value="show" />
<input type="submit" value="View My Grades" />
</form>
After this you can read the sent data "viewgrades=show" (parameter=value) in your Java-class.
Also, btw, you shouldn't use "h3" as a paragraph ("p") or section. It is intended to be a headline.