它可以作为一个代理server或者转发java类

package com.xxx.first;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.HttpURLConnection;
import java.net.URL;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.compress.utils.IOUtils;

public class SimpleProxy {

/**
* 使用GET提交到目标server。
*
* @param request
* @param response
* @param targetUrl
* @throws IOException
*/
private void get(HttpServletRequest request, HttpServletResponse response,
String targetUrl) throws IOException {

URL url = new URL(targetUrl);

BufferedReader in = new BufferedReader(new InputStreamReader(
url.openStream()));

String line;
PrintWriter out = response.getWriter();
while ((line = in.readLine()) != null) {
out.println(line);
}
out.flush();
in.close();
}

/**
* 使用POST提交到目标server。
*
* @param request
* @param response
* @param targetUrl
* @throws IOException
*/
private void post(HttpServletRequest request, HttpServletResponse response,
String targetUrl) throws IOException {
URL url = new URL(targetUrl);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();

// 发送POST请求必须设置例如以下两行
conn.setDoOutput(true);
conn.setDoInput(true);
conn.setRequestMethod("POST");
// 能够拷贝client的head信息作为请求的head參数
// conn.setRequestProperty("Charsert", "UTF-8");
conn.setRequestProperty("Content-Type", "application/json");

// 直接把client的BODY传给目标server
OutputStream send = conn.getOutputStream();
InputStream body = request.getInputStream();
IOUtils.copy(body, send);
send.flush();
send.close();
body.close();

// 获取返回值
BufferedReader in = new BufferedReader(new InputStreamReader(
conn.getInputStream()));
PrintWriter out = response.getWriter();
String line;
while ((line = in.readLine()) != null) {
out.println(line);
}
out.flush();
}

}