利用文件io流的方式存储（存到内部与存到SD卡）

一、存到内部

• 保存到内部
  FileOutputStream fos= openFileOutput(file_name, Context.MODE_PRIVATE);
  // 当内容需要追加的时候MODE_APPEND
  fos.write(file_content.getBytes(“utf-8”)); // 转换成utf-8字节编码

• 从内部读取文件
  FileInputStream fis = openFileInput(file_name);
  BufferedReader br = new BufferedReader(new InputStreamReader(fis));
  String msg = “”;
  StringBuffer stringBuffer = new StringBuffer();
  while ((msg = br.readLine()) != null) {
  stringBuffer.append(msg);
  }
  二、保存数据到sd卡
  // 判断sdcard卡是否可用
  if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
  String file_name = et_filename.getText().toString().trim();
  String file_content = et_filecontent.getText().toString().trim();
  //sd卡的路径
  String path = Environment.getExternalStorageDirectory().getAbsolutePath();
  try {
  FileOutputStream fos = new FileOutputStream(path + “/” + file_name);
  fos.write(file_content.getBytes(“utf-8”));
  Toast.makeText(getApplicationContext(), “save to sdcard success”, 0).show();}}

• 从SD卡读取数据
  // 判断sdcard卡是否可用
  if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
  String file_name = et_filename.getText().toString().trim();
  //在genymotion上路径：mnt/shell/emulated/0 需给两个权限读写sdcard的权限
  String path = Environment.getExternalStorageDirectory().getAbsolutePath();
  try {
  FileInputStream fis = new FileInputStream(path + “/” + file_name);
  BufferedReader br = new BufferedReader(new InputStreamReader(fis));
  String msg = “”;
  StringBuffer stringBuffer = new StringBuffer();
  while ((msg = br.readLine()) != null) {
  stringBuffer.append(msg);
  }

读取sd卡需要两个权限
android.permission.MOUNT_UNMOUNT_FILESYSTEMS”
android.permission.WRITE_EXTERNAL_STORAGE”