message
description The server encountered an internal error () that prevented it from fulfilling this request.
exception
java.lang.NullPointerException
com.lala.servlets.LoginServlet.service(LoginServlet.java:14)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
Dec 26, 2012 1:16:18 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for
servlet LoginServlet threw exception
java.lang.NullPointerException
at com.lala.servlets.LoginServlet.service(LoginServlet.java:14)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:849)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:454)
at java.lang.Thread.run(Unknown Source)
code:
package com.lala.servlets;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
public class LoginServlet extends HttpServlet{
public void init(ServletConfig sc){
System.out.println("init() login servlet");
}
public void service(HttpServletRequest req,HttpServletResponse res)throws IOException,ServletException{
System.out.println("service() login servlet");
String un=req.getParameter("username");
String pw=req.getParameter("password");
String msg=" ";
if(un.equals(pw)){
msg="Hello"+un+"!your login is sucessful";
}else{
msg="hello"+un+"!your login failed";
}
res.setContentType("text/html");
PrintWriter out=res.getWriter();
System.out.println("<fontsize=6 color=red>"+msg+"<font>");
}
public void destroy(){
System.out.println("destroy() login servlet");
}
}