打开失败: ENOENT (无此类文件或目录)错误将文件从资产复制到SdCard

AssetManager assetManager = getAssets();
try {
    InputStream inputStream = assetManager.open("filename.ext");
    // 文件存在，可以进行复制操作
} catch (IOException e) {
    // 文件不存在，处理错误
}

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE)
        != PackageManager.PERMISSION_GRANTED) {
    // 权限未授予，请求权限
    ActivityCompat.requestPermissions(this,
            new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},
            REQUEST_CODE);
} else {
    // 权限已授予，进行文件复制操作
}

AssetManager assetManager = getAssets();
try {
    InputStream inputStream = assetManager.open("filename.ext");
    File outputFile = new File(Environment.getExternalStorageDirectory(), "filename.ext");
    OutputStream outputStream = new FileOutputStream(outputFile);
    byte[] buffer = new byte[1024];
    int length;
    while ((length = inputStream.read(buffer)) > 0) {
        outputStream.write(buffer, 0, length);
    }
    outputStream.flush();
    outputStream.close();
    inputStream.close();
    // 文件复制成功
} catch (IOException e) {
    // 复制过程中发生错误
}