myajaxcontroller.java

实现Ajax的经典实例

package hello.ajax.sample;

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

import javax.servlet.*;
import javax.servlet.http.*;

public class MyAjaxController
  extends HttpServlet
{
  private static final String CONTENT_TYPE = "text/html; charset=windows-1252";
  private int counter = 0;
  private String name="";
  
  public void init(ServletConfig config)
    throws ServletException
  {
    super.init(config);
  }

  public void doGet(HttpServletRequest request, 
                    HttpServletResponse response)
    throws ServletException, IOException
  {
    ++counter;
    name = request.getParameter("name") != null?(String)request.getParameter("name"):null;
    
    //init cap
    name="From "+name;
    response.setContentType(CONTENT_TYPE);
    PrintWriter out = response.getWriter();
    if(counter % 2 == 0)
    {
      out.println("<b class='green'>Hello Ajax "+name+" </b><br/>");
      out.close();
    }
    else
    {
      out.println("<b class='red'>Hello Ajax "+name+" </b><br/>");
      out.close();
    }
    
  }

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