java 读写文件和文件夹好方法：

public static String getPropertyFileVlue(String propertyFilePath, String propertyName) {
    FileInputStream propertyFilenputStream = null;
    String propertyValue = "";
    try {
        if (new File(propertyFilePath).exists())
        {
            Properties pro = new Properties();
            propertyFilenputStream = new FileInputStream(propertyFilePath);
            pro.load(propertyFilenputStream);
            propertyValue = pro.getProperty(propertyName);
        }else
        {
            LogUtils.logd(TAG, "clear data config file is not exists!");
            return "";
        }
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        try {
            if (null != propertyFilenputStream) {
                propertyFilenputStream.close();
            }
            propertyFilenputStream = null;
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    return propertyValue;
}