Question

我使用IntelliJ IDEA在Mac上进行编程，我正在编写程序以使用递归查找大文件（1GB）。这是我到目前为止编写的代码。

public class Exercise05 {
    public static MyFilter myFilter = new MyFilter();
    public static int count = 0;

    public static void main(String[] args) throws FileNotFoundException {
        File file = new File("/");
        long startTime = System.currentTimeMillis();

        findBigFile(file);
        long endTime = System.currentTimeMillis();

        System.out.println(endTime - startTime);
        System.out.println(count);

    }

    public static void findBigFile(File file) throws FileNotFoundException {

        if (file.isFile()) {
            if (myFilter.bigFile(file)) {
                System.out.println(file.getAbsolutePath());
                System.out.println(file.length());
                count++;
            }
        } else {
            try {
                if (file.listFiles().length > 0) {
                    File[] files = file.listFiles();
                    for (File file1 : files) {
                        findBigFile(file1);
                    }
                }
            } catch (NullPointerException ex) {
                System.out.println(file.getAbsolutePath());
            }
        }
    }
}

class MyFilter {
    public boolean bigFile(File file) {
        if (file.length() > (1024 * 1024 * 1024)) {
            return true;
        } else
            return false;
    }
}

以下是我的结果示例

/.DocumentRevisions-V100
/.fseventsd
/.Spotlight-V100
/.Trashes
/Applications/.Wineskin2
/Applications/AliWangwang.app/Contents/Frameworks/Sparkle.framework/Resources/fr.lproj/fr.lproj
/Applications/AliWangwang.app/Contents/Frameworks/Sparkle.framework/Resources/fr_CA.lproj
/Applications/AliWangwang.app/Contents/Frameworks/Sparkle.framework/Versions/A/Resources/fr.lproj/fr.lproj
/Applications/AliWangwang.app/Contents/Frameworks/Sparkle.framework/Versions/A/Resources/fr_CA.lproj
/Applications/AliWangwang.app/Contents/Frameworks/Sparkle.framework/Versions/Current/Resources/fr.lproj/fr.lproj
/Applications/AliWangwang.app/Contents/Frameworks/Sparkle.framework/Versions/Current/Resources/fr_CA.lproj
/Applications/leanote.app/Contents/Frameworks/Electron Framework.framework/Frameworks
/Applications/leanote.app/Contents/Frameworks/Electron Framework.framework/Libraries/Libraries

我调试了程序，发现在评估false时，某些文件返回File.isFile()，这很奇怪。它们是文件而不是文件夹，这导致程序执行else语句。为什么要这样做？

Answer 1

javadoc声明：

public boolean isFile()

Tests whether the file denoted by this abstract pathname is a normal file. A file is normal if it is not a directory and, in addition, satisfies other system-dependent criteria. Any non-directory file created by a Java application is guaranteed to be a normal file.

Where it is required to distinguish an I/O exception from the case that the file is not a normal file, or where several attributes of the same file are required at the same time, then the Files.readAttributes method may be used.

Returns:
    true if and only if the file denoted by this abstract pathname exists and is a normal file; false otherwise

因此，在您的情况下，该文件可能不是正常文件。

编辑：
因为isDirectory（）只返回true，如果它是一个目录，你应该反转if else并改用file.isDirectory（）。

Answer 2

转换文件大小，然后进行比较以获取文件夹中的实际大文件。

double bytes = file.length();
double kilobytes = (bytes / 1024);

Answer 3

您可以尝试使用File.isDirectory()，看看它是否会返回相似的结果。

在mac中查找带递归的大文件

3 个答案: