FileUtils.java

package cn.timer.api.utils;


/**
 * @author wuqingjun
 * @email 284718418@qq.com
 * @date 2022/1/11
 */
public class FileUtils {
    /**
     * 获取文件的大小(返回到达的最高单位)
     * 比如：1024Byte就不再用Byte
     * 直接返回1KB
     * 返回值精确到小数点后2位
     * @param size 文件大小
     * @return 文件的大小 若文件不存在或者不是文件就返回 “”
     */

    public static String getSize(long size) {
        double s = (double) size;
        String unit;
        if (size != -1L) {
            int l;
            if (size < 1024L) {
                l = 0;
            } else if (size < 1024L * 1024L) {
                l = 1;
                s = (double) size / 1024L;
            } else {
                for (l = 2; size >= 1024L * 1024L; l++) {
                    size = size / 1024L;
                    if ((size / 1024L) < 1024L) {
                        s = (double) size / 1024L;
                        break;
                    }
                }
            }
            switch (l) {
                case 0:
                    unit = "Byte";
                    break;
                case 1:
                    unit = "KB";
                    break;
                case 2:
                    unit = "MB";
                    break;
                case 3:
                    unit = "GB";
                    break;
                case 4:
                    unit = "TB";
                    break;
                default:
                    unit = "ER";
            }
            String format = String.format("%.2f", s);
            return format + unit;
        }
        return "";
    }

    public static void main(String[] args) {
        System.out.println(getSize(42721));
        System.out.println(getSize(18560));
        System.out.println(getSize(37516712));
    }
}