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我需要证明用户输入路径。
因为当用户给出的不是文件夹路径而是文件路径时。程序“跌倒”。
我知道这是一个错误，但如何确保用户路径正确。

代码： 

 class PathAndWord {
    final String path;
    final String whatFind;

    PathAndWord(String path, String whatFind) {
        this.path = path;
        this.whatFind = whatFind;
    }

    boolean isProperlyInitialized() {
        return path != null && whatFind != null;
    }
}

public void askUserPathAndWord() {
    try {
        tryToAskUserPathAndWord();
    } catch (IOException | RuntimeException e) {
        System.out.println("Wrong input!");
        e.printStackTrace();
    } catch (InterruptedException e) {
        System.out.println("Interrupted.");
        e.printStackTrace();
    }
}

private void tryToAskUserPathAndWord() throws IOException, InterruptedException {
    PathAndWord pathAndWord = readPathAndWord();

    if (pathAndWord.isProperlyInitialized()) {
        performScan(pathAndWord, "GameOver.tmp");
        System.out.println("Thank you!");
    } else {
        System.out.println("You did not enter anything");
    }
}

private PathAndWord readPathAndWord() throws IOException {
    System.out.println("Please, enter a Path and Word (which you want to find):");

    BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));

    String path = readPath(bufferedReader);
    String whatFind = readWord(bufferedReader);
    return new PathAndWord(path, whatFind);
}

private String readPath(BufferedReader bufferedReader) throws IOException {
    System.out.println("Please enter a Path:");
    return bufferedReader.readLine();
}

private String readWord(BufferedReader bufferedReader) throws IOException {
    System.out.println("Please enter a Word:");
    return bufferedReader.readLine();
}

private void performScan(PathAndWord pathAndWord, String endOfWorkFileName) throws InterruptedException {
    BlockingQueue<File> queue = new LinkedBlockingQueue<File>();

    File endOfWorkFile = new File(endOfWorkFileName);
    CountDownLatch latch = new CountDownLatch(2);

    FolderScan folderScan = new FolderScan(pathAndWord.path, queue, latch,
            endOfWorkFile);
    FileScan fileScan = new FileScan(pathAndWord.whatFind, queue, latch,
            endOfWorkFile);

    Executor executor = Executors.newCachedThreadPool();
    executor.execute(folderScan);
    executor.execute(fileScan);

    latch.await();
}

问题：

  • 如何检查用户输入path是否正确？
  • 如果路径不正确，则显示消息path is wrong! Try again。
  • 能够检查单词 -whatFind是否正确，也是。
  • 需要之前点吗？
4

1 回答 1

1 
private String readPath(BufferedReader bufferedReader) throws IOException {
    boolean ok = false;
    do {
        System.out.println("Please enter a Path:");
        File f = new File(bufferedReader.readLine());
        if(f.exists() && f.isDirectory())
            ok = true;
        else
            System.err.println("Doesn't exist or is not a folder.");
    } while(!ok);
    return f.getAbsolutePath();
}

编辑：此方法执行任务“从用户读取路径，该路径存在并且是一个目录”。如果用户输入了无效的路径（不存在或文件），该方法会识别到这一点，警告用户并再次询问他们......一次又一次 - 直到他们正确回答。

如果可以的话，在本地检查数据是一个很好的习惯。稍后调用该方法时，您可以确定它会返回您期望的结果。

于 2013-02-28T09:50:38.240 回答