快速统计目录(文件夹)大小，有哪些好的算法？

[gIrl1990]

• 简单暴力，穷举遍历 commons / io / FileUtils.java

https://gitbox.apache.org/repos/asf?p=commons-io.git;a=blob;f=src/main/java/org/apache/commons/io/FileUtils.java;h=72d8f2af6910cdad49e3d50c7a06e5a28c2f37e7;hb=HEAD#l2667

    public static long sizeOfDirectory(final File directory) {
        checkDirectory(directory);
        return sizeOfDirectory0(directory);
    }

    private static long sizeOfDirectory0(final File directory) {
        final File[] files = directory.listFiles();
        if (files == null) {  // null if security restricted
            return 0L;
        }
        long size = 0;

        for (final File file : files) {
            if (!isSymlink(file)) {
                size += sizeOf0(file); // internal method
                if (size < 0) {
                    break;
                }
            }
        }

        return size;
    }

    private static long sizeOf0(final File file) {
        if (file.isDirectory()) {
            return sizeOfDirectory0(file);
        }
        return file.length(); // will be 0 if file does not exist
    }

• linux du 命令里做了哪些优化？

• Q: 有木有引入线程池或者其它优化之类的？

[gIrl1990]

参考下 https://github.com/vmchale/tin-summer

[gIrl1990]

修正问题: 有木有引入线程池或者其它优化之类的(其它统计法)？

新增参考: https://github.com/gaul/ptools