Context binder : Context « Servlets « Java

Context binder

import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

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

public class ContextBinder extends HttpServlet {

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

    //bind an object to the servlet context
        new ContextObject());

    //better display something
    response.setContentType("text/html"); out = response.getWriter();
        .println("<html><head><title>Servlet Context Attribute</title></head><body>");
    out.println("<h2>Servlet Context Attribute Bound</h2>");
    out.println("Object: "
        + getServletContext().getAttribute("com.java2s.ContextObject"));

  } //end doGet



class ContextObject {

  private Map map;

  public ContextObject() {

    map = Collections.synchronizedMap(new HashMap());

  public void put(Object key, Object value) {

    if (key == null || value == null)
      throw new IllegalArgumentException(
          "Invalid parameters passed to ContextObject.put");

    map.put(key, value);

  public Map getMap() {

    return map;


  public String getValues() {

    StringBuffer buf = new StringBuffer("");
    Set set = map.keySet();

    synchronized (map) {

      Iterator i = set.iterator();
      while (i.hasNext())
        buf.append((String) + "<br>");

    return buf.toString();


  public String toString() {

    return getClass().getName() + "[ " + map + " ]";



Related examples in the same category

1.Servlets Context Sample
2.Servlets ServletContextListener Demo
3.Context log
4.Context logger
5.Context accessor
6.Set the context parameters in web.xml
7.Log in ServletContext
8.Context Attributes Servlet
9.Using Contexts Servlet
10.Context Parameters Servlet
11.Get settings from ServletContext