Javaでデータを読み取る方法

public static void main(String[] args) {
    Scanner in = new Scanner(System.in);
  String a = in.nextLine();
  System.out.println(a);
}

 public void readTxtFile(String filePath) {
        try {
            File file = new File(filePath);
            if (file.isFile() && file.exists()) {
                InputStreamReader isr = new InputStreamReader(new FileInputStream(file), "utf-8");
                BufferedReader br = new BufferedReader(isr);
                String lineTxt = null;
                while ((lineTxt = br.readLine()) != null) {
                    System.out.println(lineTxt);
                }
                br.close();
            } else {
                System.out.println("文件不存在!");
            }
        } catch (Exception e) {
            System.out.println("文件读取错误!");
        }
    }