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Saturday, 29 March 2014

Servlets : Webserver vs Application Server


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Webserver vs Application Server
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    Servlets : Application Server



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    Application Server
    Application Server
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  • Servlets Tutorial
  • All Design Patterns Links
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    Servlets : ServletLifeCycle - Example


    Click here to watch in Youtube : https://www.youtube.com/watch?v=6AcVTFcZkCk

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     ServletInterface Project Dir Structure
    ServletLifeCycle - Example

     ServletsLifeCycle.java
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    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;

// Extend HttpServlet class
public class ServletsLifeCycle extends HttpServlet
{

  private static final long serialVersionUID = 1L;
  private int i;

  public void init() throws ServletException
  {
    System.out.println("------------------------------------------------------");
    System.out.println(" Init method is called ");
    System.out.println("------------------------------------------------------");
  }

  public void service( HttpServletRequest request, HttpServletResponse response ) throws ServletException,
                  IOException
  {
    ++i;
    System.out.println(" service method is called "+i+ " time");
    // Set response content type
    response.setContentType("text/html");

    // Actual logic goes here.
    PrintWriter out = response.getWriter();
    out.println("<h1>" + " service method is called "+i+ " time" + "</h1>");
  }

  public void destroy()
  {
    System.out.println("------------------------------------------------------");
    System.out.println(" destroy method is called ");
    System.out.println("------------------------------------------------------");
  }
}

    web.xml
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    <?xml version="1.0" encoding="ISO-8859-1"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
                      http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
  version="3.0"
  metadata-complete="true">

    <display-name>ServletsLifeCycle Application</display-name>
    <description>
        This is a simple web application with a source code organization
        based on the recommendations of the Application Developer's Guide.
    </description>

     <servlet>
        <servlet-name>ServletsLifeCycle</servlet-name>
        <servlet-class>ServletsLifeCycle</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>ServletsLifeCycle</servlet-name>
        <url-pattern>/hello</url-pattern>
    </servlet-mapping>
    
</web-app>


    index.html
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    <!DOCTYPE HTML><html lang="en"><head>
<meta charset="UTF-8">
<title>ServletsLifeCycle</title>
</head>
<body>
<p>
<h3>ServletsLifeCycle</H3>
<p></p>
<ul>
<li><a href="hello">ServletsLifeCycle Test</a></li>

</ul>
</body></html>

    Environment Used

    JDK version :1.6.0_30
    Tomcat version : 7.0.50 

    To Download HelloworldApp Project Click the below link

    https://sites.google.com/site/javaee4321/servlets/ServletsLifeCycleApp.zip?attredirects=0&d=1

    See also:

  • Servlets Tutorial
  • All Design Patterns Links
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    Servlets : Webserver


    Click here to watch in Youtube : https://www.youtube.com/watch?v=ZY6SO-qeb08

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    Webserver
    Webserver
    Webserver

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    Tuesday, 25 March 2014

    Servlets : ServletConfig


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    ServletConfig
    ServletConfig
    ServletConfig

    ServletConfig Project Dir Structure
    ServletConfig

    ServletConfigServlet.java
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    import java.io.IOException;
import java.io.PrintWriter;
import java.util.Enumeration;

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

public class ServletConfigServlet extends HttpServlet
{

  private static final long serialVersionUID = 1L;

  ServletConfig             servletConfig           = null;

  public void init( ServletConfig servletConfig )
  {
    this.servletConfig = servletConfig;
    System.out.println("\n-----------------------------------------------------");
    System.out.println("init method has been called and servlet is initialized");
    System.out.println("-----------------------------------------------------");

    System.out.println("Using 'getInitParameter(String name)' method get the value");
    String driverName = servletConfig.getInitParameter("driverName");
    System.out.println("Driver Name : " + driverName);

    System.out.println("\nUsing 'getInitParameterNames()'  method get the value");
    Enumeration<String> paramNames = servletConfig.getInitParameterNames();

    while( paramNames.hasMoreElements() )
    {
      String paramName = paramNames.nextElement();

      String value = servletConfig.getInitParameter(paramName);

      System.out.println("paramName : " + paramName + ", Value: " + value);

    }

  }

  public void doGet( HttpServletRequest request, HttpServletResponse response ) throws ServletException,
                  IOException
  {

    System.out.println("\n-----------------------------------------------------");
    System.out.println("doGet method has been called");
    System.out.println("-----------------------------------------------------");

    ServletConfig servletConfig = getServletConfig();
    System.out.println("Got servletconfig object using getServletConfig() method : " + servletConfig);
    System.out.println("Servlet Name : " + servletConfig.getServletName());
    System.out.println("ServletContext Object : " + servletConfig.getServletContext());

    response.setContentType("text/html");
    PrintWriter out = response.getWriter();
    out.print("<html><body>");
    out.print("<b>hello HTTP servlet</b>");
    out.print("</body></html>");
  }

  public void destroy()
  {
    System.out.println("-----------------------------------------------------");
    System.out.println("destroy method has been called and servlet is destroyed");
    System.out.println("-----------------------------------------------------");
  }

  public ServletConfig getServletConfig()
  {
    return servletConfig;
  }
}

    web.xml
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    <?xml version="1.0" encoding="ISO-8859-1"?>
<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" metadata-complete="true" version="3.0">
  <display-name>ServletConfigServlet</display-name>
  <description>
        This is a simple web application with a source code organization
        based on the recommendations of the Application Developer's Guide.
    </description>
  <servlet>
    <servlet-name>ServletConfigServlet</servlet-name>
    <servlet-class>ServletConfigServlet</servlet-class>
    
     <init-param>  
      <param-name>driverName</param-name>  
      <param-value>oracle.jdbc.driver.OracleDriver</param-value>  
    </init-param>
    
     <init-param>  
      <param-name>username</param-name>  
      <param-value>ram</param-value>  
    </init-param>
    
    <init-param>  
      <param-name>password</param-name>  
      <param-value>ram</param-value>  
    </init-param>   
    
  </servlet>
  
  <servlet-mapping>
    <servlet-name>ServletConfigServlet</servlet-name>
    <url-pattern>/servletConfig</url-pattern>
  </servlet-mapping>
</web-app>

    index.html
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    <!DOCTYPE HTML><html lang="en"><head>
<meta charset="UTF-8">
<title>ServletConfigServlet</title>
</head>
<body>
<p>
<h3>ServletConfigServlet</H3>
<p></p>
<ul>

<li><a href="servletConfig">ServletConfigServlet</a></li>

</ul>
</body></html>

    Environment Used: 

    JDK version :1.6.0_30
    Tomcat version : 7.0.50 

    To Download ServletConfigApp Project Click the below link

    https://sites.google.com/site/javaee4321/servlets/ServletConfigApp.zip?attredirects=0&d=1

    See also:

  • Servlets Tutorial
  • All Design Patterns Links
    • Posted by at No comments:
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    Monday, 24 March 2014

    Servlets : HTTPServlet


    Click here to watch in Youtube : https://www.youtube.com/watch?v=JUFBrXOgAlk

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    HTTPServlet

     HTTPServlet Project Dir Structure

    HTTPServlet

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

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

public class HelloHttpServlet extends HttpServlet
{

  private static final long serialVersionUID = 1L;

  ServletConfig             config           = null;

  public void init( ServletConfig config )
  {
    this.config = config;
    System.out.println("-----------------------------------------------------");
    System.out.println("init method has been called and servlet is initialized");
    System.out.println("-----------------------------------------------------");
  }

  public void doGet( HttpServletRequest request, HttpServletResponse response ) throws ServletException,
                  IOException
  {

    System.out.println("-----------------------------------------------------");
    System.out.println("doGet method has been called");
    System.out.println("-----------------------------------------------------");

    response.setContentType("text/html");

    PrintWriter out = response.getWriter();
    out.print("<html><body>");
    out.print("<b>hello HTTP servlet</b>");
    out.print("</body></html>");
  }

  public void destroy()
  {
    System.out.println("-----------------------------------------------------");
    System.out.println("destroy method has been called and servlet is destroyed");
    System.out.println("-----------------------------------------------------");
  }

}

    web.xml
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    <?xml version="1.0" encoding="ISO-8859-1"?>
<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" metadata-complete="true" version="3.0">
  <display-name>HelloHttpServlet</display-name>
  <description>
        This is a simple web application with a source code organization
        based on the recommendations of the Application Developer's Guide.
    </description>
  <servlet>
    <servlet-name>HelloHttpServlet</servlet-name>
    <servlet-class>HelloHttpServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>HelloHttpServlet</servlet-name>
    <url-pattern>/helloHttpServlet</url-pattern>
  </servlet-mapping>
</web-app>

    index.html
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    <!DOCTYPE HTML><html lang="en"><head>
<meta charset="UTF-8">
<title>HelloHttpServlet</title>
</head>
<body>
<p>
<h3>HelloHttpServlet</H3>
<p></p>
<ul>

<li><a href="helloHttpServlet">HelloHttpServlet</a></li>

</ul>
</body></html>

    Environment Used: 

    JDK version :1.6.0_30
    Tomcat version : 7.0.50 

    To Download HTTPServletApp Project Click the below link

    https://sites.google.com/site/javaee4321/servlets/HTTPServletApp.zip?attredirects=0&d=1 

    See also:

  • Servlets Tutorial
  • All Design Patterns Links
    • Posted by at 1 comment:
    Labels:

    Sunday, 23 March 2014

    Servlets : GenericServlet


    Click here to watch in Youtube : https://www.youtube.com/watch?v=ieweBKuDVe8

     Click the below Image to Enlarge
    GenericServlet

    GenericServlet Project Dir Structure
    GenericServlet
    HelloGenericServlet.java

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

import javax.servlet.GenericServlet;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

public class HelloGenericServlet extends GenericServlet
{

  private static final long serialVersionUID = 1L;

  ServletConfig             config           = null;

  public void init( ServletConfig config )
  {
    this.config = config;
    System.out.println("-----------------------------------------------------");
    System.out.println("init method has been called and servlet is initialized");
    System.out.println("-----------------------------------------------------");
  }

  public void service( ServletRequest req, ServletResponse res ) throws IOException, ServletException
  {
    System.out.println("-----------------------------------------------------");
    System.out.println("service method has been called");
    System.out.println("-----------------------------------------------------");

    res.setContentType("text/html");  
      
    PrintWriter out=res.getWriter();  
    out.print("<html><body>");  
    out.print("<b>hello generic servlet</b>");  
    out.print("</body></html>");  

  }

  public void destroy()
  {
    System.out.println("-----------------------------------------------------");
    System.out.println("destroy method has been called and servlet is destroyed");
    System.out.println("-----------------------------------------------------");
  }

}

    web.xml

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    <?xml version="1.0" encoding="ISO-8859-1"?>
<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" metadata-complete="true" version="3.0">
  <display-name>HelloGenericServlet</display-name>
  <description>
        This is a simple web application with a source code organization
        based on the recommendations of the Application Developer's Guide.
    </description>
  <servlet>
    <servlet-name>HelloGenericServlet</servlet-name>
    <servlet-class>HelloGenericServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>HelloGenericServlet</servlet-name>
    <url-pattern>/helloGenericServlet</url-pattern>
  </servlet-mapping>
</web-app>

    index.html

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    <!DOCTYPE HTML><html lang="en"><head>
<meta charset="UTF-8">
<title>HelloGenericServlet</title>
</head>
<body>
<p>
<h3>HelloGenericServlet</H3>
<p></p>
<ul>

<li><a href="helloGenericServlet">HelloGenericServlet</a></li>

</ul>
</body></html>

    Environment Used: 

    JDK version :1.6.0_30
    Tomcat version : 7.0.50

    To Download GenericServletApp Project Click the below link

    https://sites.google.com/site/javaee4321/servlets/GenericServletApp.zip?attredirects=0&d=1 

     See also:

  • Servlets Tutorial
  • All Design Patterns Links
    • Posted by at No comments:
    Labels:

    Servlets : Client Server Architecture of the Internet | Client--server Model


    Click here to watch in Youtube :  https://www.youtube.com/watch?v=b5l8D3YBcdI

     Click the below Image to Enlarge
    Client Server Architecture of the Internet | Client--server Model
    Client Server Architecture of the Internet | Client--server Model

    See also:

  • Servlets Tutorial
  • All Design Patterns Links
    • Posted by at No comments:
    Labels:

    Servlets : Client Server Architecture | Client--server Model


    Click here to watch in Youtube :  https://www.youtube.com/watch?v=6g62gt5f0TI

     Click the below Image to Enlarge
    Client Server Architecture | Client--server Model
    See also:

  • Servlets Tutorial
  • All Design Patterns Links
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    Labels:

    Servlets : What is Server


    Click here to watch in Youtube : https://www.youtube.com/watch?v=WovjF_nTJdY

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    What is Server

    See also:

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  • All Design Patterns Links
    • Posted by at No comments:
    Labels:

    Servlets : Servlet Interface


    Click here to watch in Youtube :  https://www.youtube.com/watch?v=X9AheaJGMBI

     Click the below Image to Enlarge
    Servlet Interface

    ServletInterface Project Dir Structure
    Servlet Interface

     FirstServlet.java

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    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;

public class FirstServlet implements Servlet
{
  ServletConfig config = null;

  public void init( ServletConfig config )
  {
    this.config = config;
    System.out.println("-----------------------------------------------------");
    System.out.println("init method has been called and servlet is initialized");
    System.out.println("-----------------------------------------------------");
  }

  public void service( ServletRequest req, ServletResponse res ) throws IOException, ServletException
  {
    System.out.println("-----------------------------------------------------");
    System.out.println("service method has been called");
    System.out.println("-----------------------------------------------------");

    res.setContentType("text/html");

    PrintWriter out = res.getWriter();
    out.print("<html><body>");
    out.print("<b>hello simple servlet</b>");
    out.print("<br>");
    out.print("<b>Servlet Info :</b> "+getServletInfo());
    out.print("<br>");
    out.print("<b>Get Servlet config object :</b> "+getServletConfig());
    
    out.print("</body></html>");

  }

  public void destroy()
  {
    System.out.println("-----------------------------------------------------");
    System.out.println("destroy method has been called and servlet is destroyed");
    System.out.println("-----------------------------------------------------");
  }

  public ServletConfig getServletConfig()
  {
    return config;
  }

  public String getServletInfo()
  {
    return "copyright 2014-01-01 version : 3.0";
  }

}

    Web.xml

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    <?xml version="1.0" encoding="ISO-8859-1"?>
<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"
 metadata-complete="true" version="3.0">
 <display-name>Servlet Interface</display-name>
 <description>
        This is a simple web application with a source code organization
        based on the recommendations of the Application Developer's Guide.
    </description>
 <servlet>
  <servlet-name>FirstServlet</servlet-name>
  <servlet-class>FirstServlet</servlet-class>

 </servlet>
 <servlet-mapping>
  <servlet-name>FirstServlet</servlet-name>
  <url-pattern>/firstServlet</url-pattern>
 </servlet-mapping>

</web-app>

    index.html

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    <!DOCTYPE HTML><html lang="en"><head>
<meta charset="UTF-8">
<title>ServletInterface</title>
</head>
<body>
<p>
<h3>ServletInterface</H3>
<p></p>
<ul>

<li><a href="firstServlet">FirstServlet</a></li>

</ul>
</body></html>

    Environment Used:

    JDK version :1.6.0_30
    Tomcat version : 7.0.50 

    To Download ServletInterfaceApp Project Click the below link

    https://sites.google.com/site/javaee4321/servlets/ServletInterfaceApp.zip?attredirects=0&d=1 
     
    See also:

  • Servlets Tutorial
  • All Design Patterns Links
    • Posted by at No comments:
    Labels:
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