转发请求实现HttpURLConnection

因为项目将用户请求转发到其他项目中，使用response重定向请求可以成功发送但是如果转发请求使用request不能实现，找了点资料自己实现一个转发类，下面是实现代码：

package com.httpproxy.servlet;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import java.io.PrintWriter;import java.math.BigDecimal;import java.util.Enumeration;import java.util.HashMap;import java.util.Map;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.apache.log4j.Logger;import com.alibaba.fastjson.JSON;import com.httpproxy.enums.APIState;import com.httpproxy.model.APIMsgModel;import com.httpproxy.model.ModelXML;import com.httpproxy.tool.PP;import com.httpproxy.tool.UtilMap;import com.httpproxy.tool.UtilProxy;/** * 请求转发代理类 *  */public class HttpProxy extends HttpServlet {    private static final Logger log = Logger.getLogger(HttpProxy.class);    private static final long serialVersionUID = 1L;    private UtilProxy util = new UtilProxy();    /**     * Default constructor.     */    public HttpProxy() {        // TODO Auto-generated constructor stub    }    /**     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse     *      response)     */    protected void doGet(HttpServletRequest request,            HttpServletResponse response) throws ServletException, IOException {        doPost(request, response);    }    protected void doPost(HttpServletRequest request,            HttpServletResponse response) throws IOException {        request.setCharacterEncoding(PP.GP("CharacterEncoding"));        long startTime = System.nanoTime();        Map<String, ModelXML> map = UtilMap.get().getMap();        // 获取访问接口名称+方法        String path = request.getServletPath();        ModelXML xml = (ModelXML) map.get(path);        if (xml != null) {            PrintWriter out = response.getWriter();            String result = null;            try {                if (xml.getType() == 1) {                    // 获取参数                    StringBuffer parameterBuffer = paermap(request);                    // 打印输入参数                    if (Boolean.parseBoolean(PP.GP("API.InParam"))) {                        HashMap<String, Object> headerMap = new HashMap<String, Object>();                        Enumeration<String> hears = request.getHeaderNames();                        while (hears.hasMoreElements()) {                            String key = hears.nextElement();                            String value = request.getHeader(key);                            headerMap.put(key, value);                        }                        log.info(Thread.currentThread().getName() + "-" + path                                + "头部信息:" + JSON.toJSONString(headerMap)                                + "输入参数:" + parameterBuffer);                    }                    result = util.proUrl(request, xml.getInnerurl(),                            parameterBuffer);                    out.write(result);                    return;                } else if (xml.getType() == 0) {                    result = xml.getNeturl();                    result = JSON.toJSONString(new APIMsgModel(APIState.S307,                            "重定向目标服务器", result));                    out.write(result);                    return;                }            } catch (Exception e) {                log.error(Thread.currentThread().getName() + "-" + path, e);                out.write(JSON.toJSONString(new APIMsgModel(APIState.S500,                        "代理服务器故障")));            } finally {                out.flush();                out.close();                // 打印输出参数                if (Boolean.parseBoolean(PP.GP("API.OutParam"))) {                    log.info(Thread.currentThread().getName() + "-" + path                            + "输出参数:" + result);                }                // 打印执行时间                if (Boolean.parseBoolean(PP.GP("API.Time"))) {                    BigDecimal consumingTime = BigDecimal.valueOf(                            System.nanoTime() - startTime).divide(                            BigDecimal.valueOf(1000000000));// /1000000000                    log.info(Thread.currentThread().getName() + "-" + path                            + "执行时间:" + consumingTime.doubleValue() + "秒");                }            }        } else {            response.setStatus(404);            return;        }    }    /**     * 获取参数     *      * @param request     * @return     * @throws Exception     */    private StringBuffer paermap(HttpServletRequest request) throws Exception {        BufferedReader in = new BufferedReader(new InputStreamReader(                request.getInputStream(), PP.GP("CharacterEncoding")));        String par = "";        StringBuffer paer = new StringBuffer();        while ((par = in.readLine()) != null) {            paer.append(par);        }        return paer;    }}

访问实现代码：

package com.httpproxy.tool;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStream;import java.io.InputStreamReader;import java.io.OutputStream;import java.io.OutputStreamWriter;import java.net.HttpURLConnection;import java.net.InetSocketAddress;import java.net.Proxy;import java.net.URL;import java.net.URLConnection;import java.util.Enumeration;import javax.servlet.http.HttpServletRequest;/** * 转发帮助类 *  * @time 2016年8月3日 下午12:50:49 */public class UtilProxy {    // 设置连接超时时间(单位毫秒)    private Integer connectTimeout = 100000;    // 设置读数据超时时间(单位毫秒)    private Integer socketTimeout = 100000;    private String proxyHost = null;    private Integer proxyPort = null;    public String proUrl(HttpServletRequest request, String url,            StringBuffer parameterBuffer) throws Exception {        URL localURL = new URL(url);        URLConnection connection = openConnection(localURL);        HttpURLConnection httpURLConnection = (HttpURLConnection) connection;        // 获取请求方式        String method = request.getMethod();        // 获取请求头部信息        Enumeration<String> hears = request.getHeaderNames();        while (hears.hasMoreElements()) {            String key = hears.nextElement();            String value = request.getHeader(key);            if (key.equals("content-type") && value == null) {                httpURLConnection.setRequestProperty("Content-Type",                        "application/x-www-form-urlencoded");            } else {                httpURLConnection.setRequestProperty(key, value);            }        }        httpURLConnection.setDoOutput(true);        httpURLConnection.setRequestMethod(method);        httpURLConnection.setRequestProperty("Accept-Charset",                PP.GP("CharacterEncoding"));        httpURLConnection.setInstanceFollowRedirects(true);        renderRequest(httpURLConnection);        OutputStream outputStream = null;        OutputStreamWriter outputStreamWriter = null;        InputStream inputStream = null;        InputStreamReader inputStreamReader = null;        BufferedReader reader = null;        StringBuffer resultBuffer = new StringBuffer();        String tempLine = null;        try {            if (method.endsWith("POST")) {                outputStream = httpURLConnection.getOutputStream();                outputStreamWriter = new OutputStreamWriter(outputStream,                        PP.GP("CharacterEncoding"));                outputStreamWriter.write(parameterBuffer.toString());                outputStreamWriter.flush();            }            if (httpURLConnection.getResponseCode() >= 300) {                throw new Exception(                        "HTTP Request is not success, Response code is "                                + httpURLConnection.getResponseCode());            }            inputStream = httpURLConnection.getInputStream();            inputStreamReader = new InputStreamReader(inputStream,                    PP.GP("CharacterEncoding"));            reader = new BufferedReader(inputStreamReader);            while ((tempLine = reader.readLine()) != null) {                resultBuffer.append(tempLine);            }        } catch (Exception e) {            throw new Exception(e);        } finally {            if (outputStreamWriter != null) {                outputStreamWriter.close();            }            if (outputStream != null) {                outputStream.close();            }            if (reader != null) {                reader.close();            }            if (inputStreamReader != null) {                inputStreamReader.close();            }            if (inputStream != null) {                inputStream.close();            }        }        // System.out.println(resultBuffer.toString());        return resultBuffer.toString();    }    /**     * 创建连接     *      * @param localURL     * @return     * @throws IOException     */    private URLConnection openConnection(URL localURL) throws IOException {        URLConnection connection;        if (proxyHost != null && proxyPort != null) {            Proxy proxy = new Proxy(Proxy.Type.HTTP, new InetSocketAddress(                    proxyHost, proxyPort));            connection = localURL.openConnection(proxy);        } else {            connection = localURL.openConnection();        }        return connection;    }    /**     * 设置请求超时时间     *      * @param connection     */    private void renderRequest(URLConnection connection) {        if (connectTimeout != null) {            connection.setConnectTimeout(connectTimeout);        }        if (socketTimeout != null) {            connection.setReadTimeout(socketTimeout);        }    }}