頁面訪問量統計實例

    import java.io.IOException;
    import java.io.PrintWriter;
    import javax.servlet.ServletContext;
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    public class CounterServlet extends HttpServlet{
          public void doGet(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException{
                 ServletContext context = getServletContext();
                 Integer count = null;
                 synchronized(context){
                     count = (Integer) context.getAttribute("counter");
                     if (null == count){
                         count = new Integer(1);
                     }
                     else{
                         count = new Integer(count.intValue() + 1);
                     }
                     context.setAttribute("counter", count);
                }
                resp.setContentType("text/html;charset=gb2312");
                PrintWriter out = resp.getWriter();
                out.println("");
                out.println("該頁面已被訪問了" + "" + count + "" + "次");
                out.close();
         }
    }