/**                         从网络地址url下载文件读成字符串
 * @param downloadUrl       文件的网络地址
 * @return
 */
public static StringBuffer downloadFromUrl(String downloadUrl) {
    BufferedReader reader = null;
    StringBuffer stringBuffer = new StringBuffer();
    String line;
    try {
        URL url = new URL(downloadUrl);
        reader = new BufferedReader(new   InputStreamReader(url.openStream()));
        while ((line = reader.readLine()) != null) {
            stringBuffer.append(line);
        }
        return stringBuffer;
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        try {
            if (reader != null) {
                reader.close();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    return null;
}

public static void saveAsFile(String content,String fileName) throws FileNotFoundException {
    File file=new File(fileName);
    PrintStream ps =new PrintStream(new FileOutputStream(file));
    ps.append(content);
    ps.flush();
}