myutility.java

来自「使用java技术写的一个图像处理框架,实现了目录树,分割窗格,任务栏图标等技术」· Java 代码 · 共 76 行

import java.io.File;
import java.util.Vector;
class MyUtility {
    private static String osName = System.getProperty("os.name").toLowerCase();
    private static File roots[] = null;
    public static String length2KB(long length) {
        long KB = 1024;
        long MB = 1024 * 1024;

        if (length == 0) {
            return String.valueOf("0 KB ");
        }

        String kbStr = "";
        long mbCount = length / MB;

        long kbCount = ((length - mbCount * MB) + 1023) / KB;

        if (mbCount != 0) {
            kbStr += String.valueOf(mbCount + ",");
        }

        if (kbCount == 0) {
            if (mbCount == 0) {
                kbStr += String.valueOf("0 KB ");
            } else {
                kbStr += String.valueOf("000 KB ");
            }
        } else {
            kbStr += String.valueOf(kbCount + " KB ");
        }

        return kbStr;
    }

    static class FileSystemRoot extends File {
        public FileSystemRoot(File f) {
            super(f, "");
        }

        public FileSystemRoot(String s) {
            super(s);
        }

        public boolean isDirectory() {
            return true;
        }
    }

    public static File[] getRoots() {
        if (roots == null) {
            constructRoots();
        }
        return roots;
    }

    private static void constructRoots() {
        if (osName.startsWith("windows")) {
            Vector rootsVector = new Vector();

            for (char c = 'C'; c <= 'Z'; c++) {
                char device[] = {c, ':', '\\'};
                String deviceName = new String(device);
                File deviceFile = new FileSystemRoot(deviceName);
                if (deviceFile != null && deviceFile.exists()) {
                    rootsVector.addElement(deviceFile);
                }
            }
            roots = new File[rootsVector.size()];
            rootsVector.copyInto(roots);
        } else {
            roots = File.listRoots();
        }
    }
}