com.feingto.cloud.kit.MD5Kit Maven / Gradle / Ivy

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package com.feingto.cloud.kit;

import lombok.extern.slf4j.Slf4j;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

/**
 * 生成大文件的MD5算法工具类
 *
 * @author longfei
 */
@Slf4j
@SuppressWarnings({"unused", "WeakerAccess"})
public class MD5Kit {
    protected static char hexDigits[] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
    protected static MessageDigest messagedigest = null;

    static {
        try {
            messagedigest = MessageDigest.getInstance("MD5");
        } catch (NoSuchAlgorithmException e) {
            log.error(MD5Kit.class.getName() + "failed to initialize, MessageDigest does not support MD5Kit.", e);
        }
    }

    public static void main(String[] args) throws IOException {
        long begin = System.currentTimeMillis();

        File big = new File("E:/Media/复仇者联盟.rmvb");

        String md5 = getFileMD5(big);

        long end = System.currentTimeMillis();
        System.out.println("md5:" + md5 + " time:" + ((end - begin) / 1000) + "s");
    }

    public static String getFileMD5(File file) {
        FileInputStream in;
        try {
            in = new FileInputStream(file);
            FileChannel ch = in.getChannel();
            MappedByteBuffer byteBuffer = ch.map(FileChannel.MapMode.READ_ONLY, 0, file.length());
            messagedigest.update(byteBuffer);
            in.close();
        } catch (IOException e) {
            throw new RuntimeException("InputStream write I/O exception.");
        }

        return bufferToHex(messagedigest.digest());
    }

    public static String getMD5String(String s) {
        return getMD5String(s.getBytes());
    }

    public static String getMD5String(byte[] bytes) {
        messagedigest.update(bytes);

        return bufferToHex(messagedigest.digest());
    }

    private static String bufferToHex(byte bytes[]) {
        return bufferToHex(bytes, bytes.length);
    }

    private static String bufferToHex(byte[] bytes, int n) {
        StringBuffer stringbuffer = new StringBuffer(2 * n);
        for (int l = 0; l < n; l++) {
            appendHexPair(bytes[l], stringbuffer);
        }
        return stringbuffer.toString();
    }

    private static void appendHexPair(byte bt, StringBuffer stringbuffer) {
        char c0 = hexDigits[(bt & 0xf0) >> 4];
        char c1 = hexDigits[bt & 0xf];
        stringbuffer.append(c0);
        stringbuffer.append(c1);
    }

    public static boolean checkPassword(String password, String md5PwdStr) {
        String s = getMD5String(password);
        return s.equals(md5PwdStr);
    }
}