Java HttpSession Example

First.java

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

/**
 * Servlet implementation class First
 */
@WebServlet("/First")
public class First extends HttpServlet {
private static final long serialVersionUID = 1L;

/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub

response.setContentType("text/html");
PrintWriter out = response.getWriter();
String n = request.getParameter("userName");
out.println("Welcome" +n);
HttpSession session = request.getSession();
session.setAttribute("uname", n);
out.println("<a href='servlet2'>Visit</a>");
out.close();

    }
}


Second.java


import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

/**
 * Servlet implementation class Second
 */
@WebServlet("/Second")
public class Second extends HttpServlet {
private static final long serialVersionUID = 1L;

/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub

response.setContentType("text/html");
PrintWriter out = response.getWriter();
HttpSession session = request.getSession(false);
String n = (String) session.getAttribute("uname");
out.print("Hello "+n);
   out.close();
}

}

OutPut:-

Java servlet program forward() and include() methods

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class First
 */
//@WebServlet("/First")
public class First extends HttpServlet {
//private static final long serialVersionUID = 1L;

/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
response.setContentType("text/html");
   PrintWriter out = response.getWriter();
       
   String n=request.getParameter("userName");
   String p=request.getParameter("userPass");
       
  out.println("First Servlet");
   if(p.equals("servlet")){
       RequestDispatcher rd=request.getRequestDispatcher("/servlet2");
       rd.forward(request, response);
   }
   else{
       out.print("Sorry UserName or Password Error!");
       RequestDispatcher rd=request.getRequestDispatcher("/First.html");
       rd.include(request, response);
                   
       }
 
}

}



import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class Sec
 */
//@WebServlet("/Sec")
public class Sec extends HttpServlet {
//private static final long serialVersionUID = 1L;

/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub






   response.setContentType("text/html");
   PrintWriter out = response.getWriter();
       
   String n=request.getParameter("userName");
   out.print("Welcome "+n);
   }


}



Output:-

Basic Performance Testing Concepts

What is performance testing?
Software performance testing is a part of QA task,which involves testing software applications to ensure that software should perform well under expected workload.

Performance testing is subset of performance engineering.Performance Engineering helps in building software with an aim to meet the performance requirements right from the requirements phase.

The objective of the functional testing is to verify and validate the functional requirements whereas the objective of performance testing is to
verify and validate the non-functional requirements (NFR) of the system related to performance.

Performance testing:-
Performance testing is done to determine the Speed,Stability and scalability under load.

Objective :-
To determine or validate speed, scalability , and/or stability.

Load Testing:-
Load testing is done to determine the application behavior (Non-functional requirements) were meeting the under expected load.

Objective:-
To verify application behavior under normal conditions.

Endurance test is a type of performance test focused on determining
application behavior when the test is conducted for long period.During endurance tests, memory consumption is observed to determine potential failures. It is also called as soak testing.
Endurance testing may be used to calculate Mean Time Between Failure (MTBF), Mean Time To Failure (MTTF), and similar metrics.

Objective:-
To verify the memory leaks

Stress Testing:-
To identify the application’s Break Point, also to measures whether the application’s environment is configured to handle the expected or unexpected load.

Objective:-
To determine the break point.

Spike testing:-A spike test is a type of performance test focused on determining or validating the  application performance when there is sudden increase in load for short periods of time.

Objective:-
To determine the application behavior when there is sudden increase in load for short time.

Why Performance Testing is important??

It is so important because once the application goes to production to generate revnivew,It should not fail (or) Crash. Failures in the prod will leads to wast or time and money.

Performance Testing helps to answer the following questions:-

a.Response time of the system under expected load?
b.System behavior under unexpected load?
c.will the system scales to a specific user load?
d.What hardware is required to the system for better performance?
e.Will the system handles spikes?

ServletContext example to get the initialization parameter from web.xml file

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class First
 */
@WebServlet("/First")
public class First extends HttpServlet {
private static final long serialVersionUID = 1L;

/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub

response.setContentType("text/html");
PrintWriter pw = response.getWriter();
ServletContext context=getServletContext();
String drivername = context.getInitParameter("dname");
pw.println("Driver Name is" +drivername);
pw.close();
}

}

web.xml

<web-app>  

  

<servlet>  

<servlet-name>First</servlet-name>  

<servlet-class>First</servlet-class>  

</servlet>  

  

<context-param>  

<param-name>dname</param-name>  

<param-value>sun.jdbc.odbc.JdbcOdbcDriver</param-value>  

</context-param>  

  

<servlet-mapping>  

<servlet-name>First</servlet-name>  

<url-pattern>/context</url-pattern>  

</servlet-mapping>  

  

</web-app>  

Output:-

ServletConfig example to get initialization parameter from web.xml

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class First
 */
@WebServlet("/First")
public class First extends HttpServlet {
private static final long serialVersionUID = 1L;

/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
response.setContentType("text/html");
   PrintWriter out = response.getWriter();
   
   ServletConfig config=getServletConfig();
   String driver=config.getInitParameter("driver");
   out.print("Driver is: "+driver);
       
   out.close();


}

}

Web.xml

<web-app>  

  

<servlet>  

<servlet-name>First</servlet-name>  

<servlet-class>First</servlet-class>  

  

<init-param>  

<param-name>driver</param-name>  

<param-value>sun.jdbc.odbc.JdbcOdbcDriver</param-value>  

</init-param>  

  

</servlet>  

  

<servlet-mapping>  

<servlet-name>First</servlet-name>  

<url-pattern>/servlet1</url-pattern>  

</servlet-mapping>  

  

</web-app>  

Output:-

Create a servlet example using (Implementing) Servlet interface

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.Servlet;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class First
 */
@WebServlet("/First")
//public class First extends HttpServlet {
// private static final long serialVersionUID = 1L;

/**
* @see HttpServlet#service(HttpServletRequest request, HttpServletResponse response)
*/
// protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
// }

//}




public class First implements Servlet{

ServletConfig con = null;

public void init(ServletConfig con){
this.con = con;
System.out.println("I am in init");
}

public void service(ServletRequest req,ServletResponse res) throws IOException,ServletException{
res.setContentType("text/html");
PrintWriter out = res.getWriter();
out.print("<html><body>");
out.print("<b>I am in Service</b>");
out.print("</html></body>");
}

public void destroy(){
System.out.println("I am in Destroy");
}
public ServletConfig getServletConfig(){return con;}
public String getServletInfo(){return "copyright 2007-1010";}
}

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>Abc</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>
</web-app>

Output:-

First Java Servlet Program

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class Hello
 */
@WebServlet("/Hello")
public class Hello extends HttpServlet {
private static final long serialVersionUID = 1L;

/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub

response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.print("<html><body>");
out.print("<b>I am in Service</b>");
out.print("</html></body>");

}

}

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>SecondServlet</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>
</web-app>

Output:-