I can't call a method inside of Servlet doPost
959343Aug 31 2012 — edited Aug 31 2012How can i call a method inside of doPost method?
JSP code:
<%@ 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 name="f1" action="sessionservlet" method="post">
Username<input type="text" name="s1">
Password<input type="password" name="s2">
<input type="submit" name="b1" value="Click">
</form>
</body>
</html>
Servlet code:
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Date;
import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
/**
* Servlet implementation class sessionservlet
*/
public class sessionservlet extends HttpServlet
{
static HttpSession session;static long l;
private static final long serialVersionUID = 1L;
/**
* Default constructor.
*/
public sessionservlet() {
// TODO Auto-generated constructor stub
}
//How can i use this method in doPost method
Object display()
{
long l=session.getLastAccessedTime();
Date d=new Date(l);
return d;
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException,NullPointerException {
// TODO Auto-generated method stub
response.setContentType("text/html");
PrintWriter out=response.getWriter();
String s=request.getParameter("s1");
out.println(s);
sessionservlet ser=new sessionservlet();
System.out.println(ser.display());
}
}
I got HTTP status 500 error
type Exception report
message
description The server encountered an internal error () that prevented it from fulfilling this request.
exception
java.lang.NullPointerException
sessionservlet.display(sessionservlet.java:30)
sessionservlet.doPost(sessionservlet.java:54)
javax.servlet.http.HttpServlet.service(HttpServlet.java:641)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
note The full stack trace of the root cause is available in the Apache Tomcat/7.0.28 logs.