public class ConcurrentTest extends HttpServlet {
    PrintWriter output;
    @Override
    protected void service(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        String  username;
        response.setContentType("text/html;charset=gb2312");
        username=request.getParameter("Username");
        output=response.getWriter();
        try {
            //为了突出并发问题,在这设置一个延时
            Thread.sleep(5000);
            output.println("用户名:"+username+"<BR>");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}部署在tomcat7上public class SimpleServlet extends HttpServlet{
       // A variable that is NOT thread-safe!
       private int counter = 0;
       public void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
              doPost(req, resp);
       }
       public void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException
       {
              resp.getWriter().println("<HTML><BODY>");
              resp.getWriter().println(this + " ==> ");
              resp.getWriter().println(Thread.currentThread() + ": <br>");
              for (int c = 0; c < 10; c++){
                     resp.getWriter().println("Counter = " + counter + "<BR>");
                     try {
                            Thread.sleep((long) Math.random() * 1000);
                            counter++;
                     }
                     catch (InterruptedException exc){}
              }
              resp.getWriter().println("</BODY></HTML>");
       }
}和第一个例子似乎差不多,只是变量由PrintWriter变成了int。    <HTML>  
      
    <BODY>  
      
    <TABLE>  
        <TR>  
            <TD><IFRAME src="./SimpleServlet" name="servlet1" height="200%"> </IFRAME></TD>  
        </TR>  
        <TR>  
            <TD><IFRAME src="./SimpleServlet" name="servlet2" height="200%"> </IFRAME></TD>  
        </TR>  
        <TR>  
            <TD><IFRAME src="./SimpleServlet" name="servlet3" height="200%"> </IFRAME></TD>  
        </TR>  
    </TABLE>  
    </BODY>  
    </HTML>  在tomcat7下 结果是 参考资料
两个例子分别来自下面两个地址 详细信息大家自己去看看吧
原文地址:http://blog.csdn.net/dlf123321/article/details/42369817