Java文件I/O问题: file now written by newBufferedWriter

Question

我写了一个小工具，用于将给定目录下的所有目录和文件名打印到文件中。程序编译正常，但运行程序后，文件未写入。这对我来说看起来很奇怪。程序代码如下所示。

在代码的第49行，当我仅使用file作为方法的参数时，没有问题并且输出文件被写入。请尝试一下并查看结果。但是当我使用 file.getFileName() 作为参数时，输出文件根本没有被写入!

非常感谢您的帮助。

/**
 * This program walks a directory tree
 * and prints out the directory name and the file names under it.
 * @author Michael Mei
 * @version 1.0 22-03-2020
 */

package walkDirectory;

import java.io.*;
import java.nio.file.*;
import java.nio.file.attribute.*;
import static java.nio.file.FileVisitResult.*;
import static java.nio.file.FileVisitOption.*;
import java.nio.charset.StandardCharsets;
import java.util.*;

public class DirWalkerPrinter extends SimpleFileVisitor<Path> {
    private Path outPath;
    private Writer out;
    private int fileCount;
    private int dirCount;

    DirWalkerPrinter (Path outPath) throws IOException {
        this.outPath = outPath;
        out = Files.newBufferedWriter(outPath, StandardCharsets.UTF_16, StandardOpenOption.WRITE);
    }

    public int getFileCount () {
        return fileCount;
    }

    public int getDirCount () {
        return dirCount;
    } 

    public void writeResults(Path p) throws IOException {
        // Using System.out.println(p.toString()) was also working.
        out.write(p.toString());
        out.write("\n");
    }

    public void done () throws IOException {
        out.write(fileCount + " of files found in " + dirCount);
    }

    @Override
    public FileVisitResult visitFile (Path file, BasicFileAttributes attrs) throws IOException {
        writeResults(file.getFileName()); // line 49
        fileCount++;
        return CONTINUE;
    }

    public FileVisitResult postVisitDirectory (Path dir, BasicFileAttributes attrs) throws IOException {
        writeResults(dir);
        dirCount++;
        return CONTINUE;
    }
    @Override
    public FileVisitResult visitFileFailed (Path file, IOException e) {
        System.err.println(e);
        return CONTINUE;
    }

    public static void main(String[] args) throws IOException {
        if (args.length < 2) {
        System.err.println("java DirWalkerPrinter source-path destination-file");
        System.exit(-1);
    }
        Path startingDir = Paths.get(args[0]);
        Path writeToDir = Paths.get(args[1]);
        DirWalkerPrinter dirWalkerPrinter = new DirWalkerPrinter(writeToDir);
        Files.walkFileTree(startingDir, dirWalkerPrinter);
        dirWalkerPrinter.done();
        int fileCount = dirWalkerPrinter.getFileCount();
        int dirCount = dirWalkerPrinter.getDirCount();
        System.out.println(fileCount + " of files found in " + dirCount);
    }
}

Answer 1

file.getFileName()

此函数将仅返回文件名 - 没有完整路径。您的代码将尝试在您执行的同一目录中创建该文件。 (因为你只输入文件名)

这可能是您的问题。