public class FileProvider extends ContentProvider {
    private static final String AUTHORITY = "com.example.fileprovider";
    private static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/file");

    // 文件鎖，確保單進(jìn)程寫(xiě)入
    private static final Object fileLock = new Object();

    @Override
    public boolean onCreate() {
        return true;
    }

    @Override
    public Cursor query(Uri uri, String[] projection, 
        String selection, String[] selectionArgs, String sortOrder) {
        return null; // 不提供查詢(xún)功能
    }

    @Override
    public String getType(Uri uri) {
        return null;
    }

    @Override
    public Uri insert(Uri uri, ContentValues values) {
        return null; // 不提供插入功能
    }

    @Override
    public int delete(Uri uri, String selection, String[] selectionArgs) {
        return 0; // 不提供刪除功能
    }

    @Override
    public int update(Uri uri, ContentValues values, 
        String selection, String[] selectionArgs) {
        return 0; // 不提供更新功能
    }

    // 自定義方法：寫(xiě)入文件
    @Override
    public Bundle call(String method, String arg, Bundle extras) {
        if ("writeToFile".equals(method)) {
            String content = extras.getString("content");
            synchronized (fileLock) { 
                writeToFile(content);
            }
            Bundle result = new Bundle();
            result.putBoolean("success", true);
            return result;
        }
        return super.call(method, arg, extras);
    }

    // 實(shí)際寫(xiě)入文件的邏輯
    private void writeToFile(String content) {
        File file = new File(getContext().getFilesDir(), "A.txt");
        try (FileOutputStream fos = new FileOutputStream(file, true)) {
            fos.write(content.getBytes());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

<provider
    android:name=".FileProvider"
    android:authorities="com.example.fileprovider"
    android:exported="true" />

    private void writeToFileViaProvider(String content) {
        Uri uri = Uri.parse("content://com.example.fileprovider/file");
        ContentResolver resolver = getContentResolver();
        
        Bundle extras = new Bundle();
        extras.putString("content", content);
        
        try {
            Bundle result = resolver.call(uri, "writeToFile", null, extras);
            if (result != null && result.getBoolean("success")) {
                Log.d("FileProvider", "Write successful");
            }
        } catch (Exception e) {
            Log.e("FileProvider", "Failed to write file", e);
        }
    }

public interface Channel extends Closeable {

    /**
     * Tells whether or not this channel is open.
     *
     * @return <tt>true</tt> if, and only if, this channel is open
     */
    public boolean isOpen();

    /**
     * Closes this channel.
     */
    public void close() throws IOException;

}

// 通過(guò) FileInputStream/FileOutputStream (只讀或只寫(xiě))
FileInputStream fis = new FileInputStream("file.txt");
FileChannel readChannel = fis.getChannel();

FileOutputStream fos = new FileOutputStream("file.txt");
FileChannel writeChannel = fos.getChannel();

// 通過(guò) RandomAccessFile
RandomAccessFile raf = new RandomAccessFile("file.txt", "rw");
FileChannel channel = raf.getChannel();

FileChannel channel = FileChannel.open(Paths.get("file.txt"), StandardOpenOption.READ);

public class FileWriter {

    private static final String FILE_PATH = "/path/to/your/file.txt";

    public void writeToFile(String content) {
        File file = new File(FILE_PATH);
        try {
            FileOutputStream fos = new FileOutputStream(file, true);
            FileChannel channel = fos.getChannel()) 
            // 獲取獨(dú)占鎖
            FileLock lock = channel.lock();
            try {
                // 寫(xiě)入文件
                fos.write(content.getBytes());
            } finally {
                // 釋放鎖
                lock.release();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}