Jetty Servlet+ HttpClient 製做的 Java HttpProxy

最近學習了一下Jetty，從http://iamrunning.iteye.com/blog/410253 看到不錯的代碼，因此轉過來

 所須要的Jar包

jetty-6.1.18.jar

jetty-client-6.1.18.jar

 jetty-sslengine-6.1.18.jar

jetty-util-6.1.18.jar

servlet-api-2.5-20081211.jar

package net.chenpu.http;

import java.io.IOException;
import java.util.Enumeration;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.mortbay.io.Buffer;
import org.mortbay.io.BufferUtil;
import org.mortbay.jetty.Server;
import org.mortbay.jetty.client.Address;
import org.mortbay.jetty.client.ContentExchange;
import org.mortbay.jetty.client.HttpClient;
import org.mortbay.jetty.client.security.ProxyAuthorization;
import org.mortbay.jetty.servlet.Context;
import org.mortbay.jetty.servlet.ServletHolder;

public class HttpProxy {
    public static void main(String[] args) throws Exception {
        Server server = new Server(8001);
        Context context = new Context(server, "/", Context.SESSIONS);
        context.addServlet(new ServletHolder(new LocalProxyServlet()), "/*");

        server.start();
        server.join();
    }

    @SuppressWarnings("serial")
    public static class LocalProxyServlet extends HttpServlet {

        private HttpClient client = new HttpClient();

        public LocalProxyServlet() {
            client.setConnectorType(HttpClient.CONNECTOR_SELECT_CHANNEL);
            // if you need,set proxy gate
            // client.setProxy(new Address("127.0.0.1",8080));
            // try {
            // client.setProxyAuthentication(new
            // ProxyAuthorization("user","password"));
            // } catch (IOException e1) {
            // // TODO Auto-generated catch block
            // e1.printStackTrace();
            // }
            try {
                client.start();
            } catch (Exception e) {
                throw new RuntimeException(e);
            }

        }

        @Override
        protected void service(HttpServletRequest request,
                final HttpServletResponse response) throws ServletException,
                IOException {
            StringBuilder accessPath = new StringBuilder(request
                    .getRequestURL().toString());
            System.out.println("access " + accessPath);
            ContentExchange exchange = new ContentExchange() {
                // improve performance... waiting
                @Override
                protected void onResponseHeader(Buffer name, Buffer value)
                        throws IOException {
                    String nameStr = BufferUtil.to8859_1_String(name);
                    String valueStr = BufferUtil.to8859_1_String(value);
                    response.setHeader(nameStr, valueStr);
                }

                @Override
                protected void onResponseContent(Buffer content)
                        throws IOException {
                    response.getOutputStream().write(content.asArray());
                }

                @Override
                protected void onResponseStatus(Buffer version, int status,
                        Buffer reason) throws IOException {
                    response.setStatus(status);
                }

                @Override
                protected void onConnectionFailed(Throwable ex) {
                    // TODO Auto-generated method stub
                    ex.printStackTrace();
                    response.setStatus(500);
                }

                @Override
                protected void onException(Throwable ex) {
                    // TODO Auto-generated method stub
                    ex.printStackTrace();
                    response.setStatus(500);
                }
            };

            // set jetty http client request params
            exchange.setMethod(request.getMethod());
            if (request.getMethod().equalsIgnoreCase("GET")) {
                Enumeration<String> params = request.getParameterNames();
                if (params != null) {
                    if (params.hasMoreElements()) {
                        accessPath.append('?');
                    }
                    while (params.hasMoreElements()) {
                        String name = params.nextElement();
                        String value = request.getParameter(name);
                        accessPath.append(name);
                        if (value != null) {
                            accessPath.append('=').append(value);
                        }
                        if (params.hasMoreElements()) {
                            accessPath.append('&');
                        }
                    }
                }
            }
            // set request url
            exchange.setURL(accessPath.toString());
            // set http header
            Enumeration<String> headers = request.getHeaderNames();
            while (headers.hasMoreElements()) {
                String name = headers.nextElement();
                String value = request.getHeader(name);
                exchange.setRequestHeader(name, value);
            }

            if (request.getInputStream() != null)
                exchange.setRequestContentSource(request.getInputStream());

            // start the exchange
            client.send(exchange);
            try {
                exchange.waitForDone();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}