servlet的多线程并发问题

package gz.itcast.e_thread;
 
import java.io.IOException;
 
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
 * servlet的多线程并发问题
 * @author APPle
 *
 */
public class TheradDemo extends HttpServlet {
 
    int count = 1;
 
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html;charset=utf-8");
 
        synchronized (TheradDemo.class) {//锁对象必须唯一。建议使用类对象
            response.getWriter().write("你现在是当前网站的第"+count+"个访客");   //线程1执行完  ， 线程2执行
 
        //线程1还没有执行count++
        /*try {
            Thread.sleep(5000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }*/
            count++;
        }
    }
 
}