这是我的代码：

// Local database

InputStream input = new FileInputStream(from);

// create directory for backup

File dir = new File(DB_BACKUP_PATH);

dir.mkdir();

// Path to the external backup

OutputStream output = new FileOutputStream(to);

// transfer bytes from the Input File to the Output File

byte[] buffer = new byte[1024];

int length;

while ((length = input.read(buffer))>0) {

output.write(buffer, 0, length);

}

output.flush();

output.close();

input.close();