J2EE基础：Servlet实现代理服务器功能

import java.io.*;
import java.net.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class Proxy extends HttpServlet
{ public void doGet(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException
{ String query = null;

response.setContentType("text/html");
PrintWriter out = response.getWriter();

query = request.getParameter("URL");
if (query == null)
{ response.sendError(HttpServletResponse.SC_BAD_REQUEST,
"Missing URL parameter");
return;
}

try
{ query = URLDecoder.decode(query);
}
catch(Exception exception)
{ response.sendError(HttpServletResponse.SC_BAD_REQUEST,
"URL decode error " + exception);
return;
}

try
{ URL url = new URL(query);
BufferedReader in = new BufferedReader(new
InputStreamReader(url.openStream()));

String line;
while ((line = in.readLine()) != null)
out.println(line);
out.flush();
}
catch(IOException exception)
{ response.sendError(HttpServletResponse.SC_NOT_FOUND,
"Exception: " + exception);
}
}
}