读取文件、写入文件

```java

```java
    /**
     * 读取文件
     * @param filePath
     * @return
     */
   public static String reader(String filePath) {
        try {
            File file = new File(filePath);
            if (file.isFile() && file.exists()) {
                InputStreamReader read = new InputStreamReader(new FileInputStream(file), "UTF-8");
                BufferedReader bufferedReader = new BufferedReader(read);
                String lineTxt = bufferedReader.readLine();
                while (lineTxt != null) {
                    return lineTxt;
                }
            }
        } catch (UnsupportedEncodingException | FileNotFoundException e) {
            Log.e("FileUtils","Cannot find the file specified!");
            e.printStackTrace();
        } catch (IOException e) {
            Log.e("FileUtils","Error reading file content!");
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 保存文件
     *
     * @param filename 路径
     * @param content 内容
     */
    public static void writeToExternalStoragePublic(String filename, String content) {
        String path = ROOTPATH + "/users/";
        Log.e("123456sss", "file" + path);
        try {
            boolean exists = (new File(path)).exists();
            if (!exists) {
                new File(path).mkdirs();
            }
            FileOutputStream fOut = new FileOutputStream(path + filename, true);
            fOut.write(content.getBytes());
            fOut.flush();
            fOut.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

/**
 * 递归删除某个目录以及目录里的东西
 *
 * @param path 要删除的目录路径   String path = ROOTPATH + "/users/PHONE";  传参
 * @return
 */
public static boolean deleteDirs(String path) {
    Log.e("128999", "path = " + path);
    File file = new File(path);
    if (!file.exists()) {
        return true;
    }
    if (file.isDirectory()) {
        File[] childs = file.listFiles();
        if (null == childs) {
            return false;
        }
        boolean result = true;
        for (File child : childs) {
            result = result && deleteDirs(child.getAbsolutePath());
        }
        Log.e("128999", "file1-------------------" + file.toString());
        try {
            boolean ret = file.delete();
            return result && ret;
        } catch (Exception e) {
            e.printStackTrace();
            return false;
        }
    } else {
        Log.e("128999", "file2-------------------" + file.toString());
        try {
            boolean ret = file.delete();
            return ret;
        } catch (Exception e) {
            e.printStackTrace();
            return false;
        }
    }
}

    /**
     * 检查是否有文件存在
     *
     * @return
     */
    public static boolean existPhoneFile() {
        String path = ROOTPATH + "/users/PHONE";
        boolean exists = (new File(path)).exists();
        return exists;
    }