copy出来的数据库文件，用数据库工具打开，提示要输密码

// copyRDB文件 
func2() { 
  let saveFile = fileIo.openSync(getContext().filesDir + '/RdbTest.db', 
    fileIo.OpenMode.READ_WRITE | fileIo.OpenMode.CREATE | fileIo.OpenMode.TRUNC); 
  let dbFile = fileIo.openSync(getContext().databaseDir + '/rdb/customDir/subCustomDir/RdbTest.db', 
    fileIo.OpenMode.READ_WRITE); 
  let dbFileLength = fileIo.statSync(dbFile.fd).size 
  let buffer = new ArrayBuffer(dbFileLength) 
  let readLength = fileIo.readSync(dbFile.fd, buffer) 
  fileIo.writeSync(saveFile.fd, buffer, { length: readLength }); 
  fileIo.close(dbFile); 
  fileIo.close(saveFile); 
}