笔记-获取APK的MD5值

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.security.MessageDigest;
/**
 * MD5加密工具类
 *
 */
public final class Md5Utils {
    private Md5Utils() {
        throw new UnsupportedOperationException("cannot be instantiated");
    }
    /**
     * 获取文件的MD5值
     *
     * @param file
     * @return
     */
    public static String getFileMD5(File file) throws Exception {
        if (file == null || !file.exists()) {
            return "";
        }
        FileInputStream fis = null;
        try {
            MessageDigest digest = MessageDigest.getInstance("MD5");
            fis = new FileInputStream(file);
            byte[] buffer = new byte[8192];
            int len;
            while ((len = fis.read(buffer)) != -1) {
                digest.update(buffer, 0, len);
            }
            return bytes2Hex(digest.digest());
        } catch (Exception e) {
            throw new Exception(e);
        } finally {
            if (fis != null) {
                try {
                    fis.close();
                } catch (IOException ignored) {
                }
            }
        }
    }
    /**
     * 一个byte转为2个hex字符
     *
     * @param src byte数组
     * @return 16进制大写字符串
     */
    private static String bytes2Hex(byte[] src) {
        char[] res = new char[src.length << 1];
        final char hexDigits[] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
        for (int i = 0, j = 0; i < src.length; i++) {
            res[j++] = hexDigits[src[i] >>> 4 & 0x0F];
            res[j++] = hexDigits[src[i] & 0x0F];
        }
        return new String(res);
    }

    public static long getFileSize(String filename) {
        File file = new File(filename);
        if (!file.exists() || !file.isFile()) {
            System.out.println("文件不存在");
            return -1;
        }
        return file.length();
    }

    public static void main(String[] args) throws Exception {

        File file = new File("F:\\iVS_Ftp\\gpsUpgradePkg\\1.7.7_565_202207050247_ZX.apk");

        String md5 = Md5Utils.getFileMD5(file);
        System.out.println(md5);

        long size = getFileSize("F:\\iVS_Ftp\\gpsUpgradePkg\\1.7.7_565_202207050247_ZX.apk");
        System.out.println("文件大小为: " + size);

    }
}