给定如下 Servlet 代码 , 假定在浏览器中输入 URL : http://localhost:8080/servlet/HelloServlet , 可以调用这个 servlet , 那么这个 Servlet 的输出是 () 。 import java.io.*; import javax.servlet.*; importjavax.servlet.http.*; publicclass HelloServlet extends HttpServlet{ public void service(HttpServletRequest req,HttpServletResponse res) throws ServletException, IOException{ } public void doGet(HttpServletRequest req,HttpServletResponse res) throws ServletException, IOException { res.setContentType("text/html"); PrintWriter out = res.getWriter(); out.println(""); out.println(""); out.println("doGet HelloWorld!"); out.println(""); out.println(""); out.close(); } public void doPost(HttpServletRequest req,HttpServletResponse res) throws ServletException, IOException { res.setContentType("text/html"); PrintWriter out = res.getWriter(); out.println(""); out.println(""); out.println("doPost HelloWorld!"); out.println(""); } } ( 选择一项 )