import
import
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class H extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
            Thread thread=new MyThread(request);
            thread.start();
    }

}
class MyThread extends Thread{
    HttpServletRequest httpServletRequest=null;
    public MyThread(HttpServletRequest httpServletRequest){
        this.httpServletRequest=httpServletRequest;
        System.out.println("构造方法中"+httpServletRequest.getSession());
    }
     @Override
    public void run() {
        while(true){
            try {
                Thread.sleep(500);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println("我是线程------"+this.getName());
            System.out.println("run方法中"+httpServletRequest.getSession());
        }
    }
}

jsp方面：--------------------------
<script type="text/javascript">
         $(function(){
             $("#b1").click(function(){
                 $.get("H",{},function(message,stutes){
                 alert(message+"--------------------");


              });   
             });


           });
         
    </script>
 <input type="button" id="b1" value="Click me" />
/*为什么上面输出httpServletRequest.getSession()的值是null,输出httpServletRequest的值就不是null呢？*/