Java 實現POST請求發送

 /**
     * 向指定 URL 發送POST方法的請求
     * @param url 發送請求的 URL
     * @param params 請求的參數集合
     * @return 遠程資源的響應結果
     */
    @SuppressWarnings("unused")
    private String sendPost(String url, Map<String, String> params) {
        OutputStreamWriter out = null;
        BufferedReader in = null;
        StringBuilder result = new StringBuilder();
        try {
            URL realUrl = new URL(url);
            HttpURLConnection conn =(HttpURLConnection) realUrl.openConnection();
            // 發送POST請求必須設置如下兩行
            conn.setDoOutput(true);
            conn.setDoInput(true);
            // POST方法
            conn.setRequestMethod("POST");
            // 設置通用的請求屬性
            conn.setRequestProperty("accept", "*/*");
            conn.setRequestProperty("connection", "Keep-Alive");
            conn.setRequestProperty("user-agent",
                    "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
            conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
            conn.connect();
            // 獲取URLConnection對象對應的輸出流
            out = new OutputStreamWriter(conn.getOutputStream(), "UTF-8");
            // 發送請求參數
            if (params != null) {
                StringBuilder param = new StringBuilder();
                for (Map.Entry<String, String> entry : params.entrySet()) {
                    if(param.length()>0){
                        param.append("&");
                    }
                    param.append(entry.getKey());
                    param.append("=");
                    param.append(entry.getValue());
                    //System.out.println(entry.getKey()+":"+entry.getValue());
                }
                //System.out.println("param:"+param.toString());
                out.write(param.toString());
            }
            // flush輸出流的緩衝
            out.flush();
            // 定義BufferedReader輸入流來讀取URL的響應
            in = new BufferedReader(
                    new InputStreamReader(conn.getInputStream(), "UTF-8"));
            String line;
            while ((line = in.readLine()) != null) {
                result.append(line);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        //使用finally塊來關閉輸出流、輸入流
        finally{
            try{
                if(out!=null){
                    out.close();
                }
                if(in!=null){
                    in.close();
                }
            }
            catch(IOException ex){
                ex.printStackTrace();
            }
        }
        return result.toString();
    }