http post header body

   /**
     * 向指定 URL 發送POST方法的請求
     * 
     * @param url
     *            發送請求的 URL
     * @param param
     *            請求參數，請求參數應該是 name1=value1&name2=value2 的形式。
     * @return 所代表遠程資源的響應結果
     */
    public static String sendPost(String url, String param, Map<String, String> header) {
        PrintWriter out = null;
        BufferedReader in = null;
        URLConnection conn = null;
        StringBuilder jsonStr = new StringBuilder();
        
        try {
            URL realUrl = new URL(url);
            // 打開和URL之間的連接
            conn = realUrl.openConnection();
            conn.setConnectTimeout(20000); 
            conn.setRequestProperty("Content-length", String.valueOf(param.length()));
            
            //添加header信息
            if(header!=null){
	            for (Map.Entry<String, String> entry : header.entrySet()) {  
	                conn.setRequestProperty(entry.getKey(),entry.getValue());
	            } 
            }
            else
            {
                // 設置通用的請求屬性
                conn.setRequestProperty("Content-Type", "application/json; charset=utf-8");
            }
            
            // 發送POST請求必須設置如下兩行
            conn.setDoOutput(true);
            conn.setDoInput(true);
            
            // 獲取URLConnection對象對應的輸出流
            out = new PrintWriter(conn.getOutputStream());
            // 發送請求參數body
            out.write(param);
            // flush輸出流的緩沖
            out.flush();
            // 定義BufferedReader輸入流來讀取URL的響應
            
            InputStreamReader reader = new InputStreamReader(conn.getInputStream(), ConstantUtil.UTF_CODE);
			char[] buff = new char[1024];
			int length = 0;
			while ((length = reader.read(buff)) != -1) {
				String result = new String(buff, 0, length);
				jsonStr.append(result);
			}
        } catch (Exception e) {
            System.out.println("發送 POST 請求出現異常！"+e);
            e.printStackTrace();
        }
        finally{
            try{    
                if(out!=null){
                    out.close();
                }
                if(in!=null){
                    in.close();
                }
            }
            catch(IOException ex){
                ex.printStackTrace();
            }
        }
        
        System.out.println("特來電返回結果：" + jsonStr.toString());
        return jsonStr.toString();
    
    }