本文记录的是使用Java获取Http请求中的参数，包括Get和Post请求。

###获取Get请求中的参数 

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protected void doGet(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
    String params = req.getQueryString();

    PrintWriter pw = resp.getWriter();
    pw.write("you get request is success: query params = " + params);
    pw.flush();
    pw.close();
    pw = null;
}

例如，若如下使用Get请求:

http://localhost:8080/nps?action=sendGet&params=location

那么上述代码中params的值为action=sendGet&params=location

###获取Post请求中的参数 

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protected void doPost(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
    int contentLength = req.getContentLength();
    //-1 indicate the length is not known
    if (-1 != contentLength) {
        byte[] requestBody = new byte[contentLength];
        for (int i = 0; i < contentLength;) {
            int readLength = req.getInputStream().read(requestBody, i,
                        contentLength - i);
            //reached the end of the stream
            if (-1 == readLength) {
                break;
            }

            i += readLength;
        }

        String charEncoding = resp.getCharacterEncoding();
        if (null == charEncoding) {
            charEncoding = "UTF-8";
        }
        String requestContent = new String(requestBody, charEncoding);

        PrintWriter pw = resp.getWriter();
        pw.write("you post request is success. posted data is: "
                    + requestContent);
        pw.flush();
        pw.close();
        pw = null;
    }
}

例如，若采用使用HttpURLConnection发送Get和Post请求示例一文中所示示例发送Post请求，那么上述代码的requestContent的值是UTF-8编码之后的action=get info&param=云竹字符串值.

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