java url處理常遇到的問題

1、通過HttpURLConnection得到的數據中文亂碼

urlConnection = (HttpURLConnection) url.openConnection();
        urlConnection.setRequestMethod(method);
urlConnection.setDoOutput(true);
urlConnection.setDoInput(true);
urlConnection.setUseCaches(false);
        urlConnection.setConnectTimeout(defaultTimeout);
urlConnection.setRequestProperty("User-Agent", "Mozilla/4.0 (compatible; MSIE 5.0; Windows NT; DigExt)");
urlConnection.setRequestProperty("Content-Type", "text/plain;charset=UTF-8");

        設置一下Content-Type，然後用下面的方式接收數據：

        InputStream in = urlConnection.getInputStream();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(in, "UTF-8"));

2、URLDecoder.decode(line, "UTF-8") 遇到如下異常

      java.lang.IllegalArgumentException: URLDecoder: Illegal hex characters in escape (%) pattern - For input string: "+%"

主要原因是% 在URL中是特殊字符，需要特殊轉義一下，使用%25替換字符串中的%號，如下：

 line = line.replaceAll("%(?![0-9a-fA-F]{2})", "%25");