java - 如何缓存/读取json文件？

Question

我在尝试缓存和读取 json 文件时遇到问题，我使用 google dev 的示例来缓存文件，然后尝试使用不同的函数 readCache()，但我在

上收到错误

outputStream.read() -> cannot resolve method read().....

有人可以解释一下我做错了什么吗？

private void cacheFile(JSONObject response) {
     JSONObject res  = response;
     String filename = "jsonfile";
     FileOutputStream outputStream;

     try {
         outputStream = openFileOutput(filename, Context.MODE_PRIVATE);
         outputStream.write(res.toString().getBytes("utf-8"));
         outputStream.close();
         Log.e(TAG, "Success");
     } catch (Exception e) {
         e.printStackTrace();
     }
}

private void readCache(String filename) {
    FileOutputStream outputStream;
    try {
        outputStream = openFileOutput(filename, Context.MODE_PRIVATE);
        outputStream.read();
        outputStream.close();
    } catch (Exception e) {
        e.printStackTrace();
    }
}

Answer 1

尝试将 readCache() 方法更改为

private void readCache(String filename) {
    FileInputStream inputStream;
    try {
        inputStream = openFileInput(filename);
        String body = inputStreamToString(inputStream);
        inputStream.close();
    } catch (Exception e) {
        e.printStackTrace();
    }
}

private String inputStreamToString(InputStream inputStream) throws Exception {
    ByteArrayOutputStream result = new ByteArrayOutputStream();
    byte[] buffer = new byte[1024];
    int length;
    while ((length = inputStream.read(buffer)) != -1) {
        result.write(buffer, 0, length);
    }
    return result.toString("UTF-8");
}