Applet用Http隧道技术和Servlet通讯 (源码)

最新推荐文章于 2022-05-10 16:54:08 发布

原创最新推荐文章于 2022-05-10 16:54:08 发布 · 333 阅读

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CC 4.0 BY-SA版权

文章标签：

#applet #servlet #通讯 #import #google #exception

本文介绍了一种利用Applet与Servlet通过HTTP隧道进行通信的方法。通过示例代码展示了如何从客户端发送数据到服务器，并由服务器返回响应。此方案适用于受限于防火墙规则的应用场景。





import java.io.*;

import java.applet.Applet;

import java.awt.*;



public class TestDataStreamApplet extends Applet

{

    String response;

    public  void  init(){     

      

      try{

         java.net.URL url = new java.net.URL(getDocumentBase(),"servlet/DataStreamEcho");         

         java.net.URLConnection con = url.openConnection(); 

         con.setUseCaches(true);

         con.setDoOutput(true);

         con.setDoInput(true);

         ByteArrayOutputStream byteout = new ByteArrayOutputStream();

         DataOutputStream out = new DataOutputStream(byteout);

         out.writeUTF("hello world!");

         out.flush();

         byte buf[] =  byteout.toByteArray();         

         con.setRequestProperty("Content-type","application/octest-stream");

         con.setRequestProperty("Content-length","" buf.length);

         DataOutputStream dataout = new DataOutputStream(con.getOutputStream());

         dataout.write(buf);

         dataout.flush();

	 dataout.close();



         DataInputStream in = new DataInputStream(con.getInputStream());

         response = in.readUTF();

         System.out.println("read from server :"   response);

         in.close();  

      }

      catch(Exception e){

         e.printStackTrace();

      }

      

   }



   public void paint(Graphics g){

      g.drawString("read from server :"   response,10,20);

       

   }

}

Servlet source





import javax.servlet.*;

import javax.servlet.http.*;

import java.io.*;



public class DataStreamEcho extends HttpServlet{

       public void service(HttpServletRequest req,HttpServletResponse resp)

           throws ServletException ,java.io.IOException

       {

           DataInputStream in = new DataInputStream(req.getInputStream());

           resp.setContentType("application/octest-stream");

           ByteArrayOutputStream byteout = new ByteArrayOutputStream();

           DataOutputStream out = new DataOutputStream(byteout);

           String response = in.readUTF();

           out.writeUTF(response);

           out.flush();

           byte buf[]= byteout.toByteArray();

           resp.setContentLength(buf.length);

           ServletOutputStream servletout = resp.getOutputStream();

           servletout.write(buf);

           servletout.close();  

       }



}

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