import java.io.File;

import java.io.FileInputStream;

import java.io.IOException;

import java.security.MessageDigest;

import org.apache.commons.codec.binary.Hex;

import org.apache.commons.codec.digest.DigestUtils;

/**

 *MD5计算工具

 */

public class Md5CaculateUtil {

    /**

     * 获取一个文件的md5值(可处理大文件)

     * @return md5 value

     */

    public static String getMD5(File file) {

        FileInputStream fileInputStream = null;

        try {

            MessageDigest MD5 = MessageDigest.getInstance("MD5");

            fileInputStream = new FileInputStream(file);

            byte[] buffer = new byte[8192];

            int length;

            while ((length = fileInputStream.read(buffer)) != -1) {

                MD5.update(buffer, 0, length);

            }

            return new String(Hex.encodeHex(MD5.digest()));

        } catch (Exception e) {

            e.printStackTrace();

            return null;

        } finally {

            try {

                if (fileInputStream != null){

                    fileInputStream.close();

                    }

            } catch (IOException e) {

                e.printStackTrace();

            }

        }

    }

    /**

     * 求一个字符串的md5值

     * @param target 字符串

     * @return md5 value

     */

    public static String MD5(String target) {

        return DigestUtils.md5Hex(target);

    }

    public static void main(String[] args) {

        long beginTime = System.currentTimeMillis();

        File file = new File("D:/1/pdi-ce-7.0.0.0-24.zip");

        String md5 = getMD5(file);

        long endTime = System.currentTimeMillis();

        System.out.println("MD5:" + md5 + "\n 耗时:" + ((endTime - beginTime) / 1000) + "s");

    }

}

package hanwl.FileDemo;

import java.io.File;

import java.io.IOException;

import java.io.InputStream;

import java.nio.file.Files;

import java.nio.file.StandardOpenOption;

import java.security.MessageDigest;

import java.security.NoSuchAlgorithmException;

public class CalcMD5 {

    private static final char[] hexCode = "0123456789ABCDEF".toCharArray();

    public static void main(String[] args) {

        long beginTime = System.currentTimeMillis();

        File file = new File("E:/云舒测试文件/20180628-北大社-中国古文字学通论.pdf");

        //File file = new File("E:/拉鲁斯法汉双解词典(12新)/制作文件库/其他/SJ00040936 拉鲁斯法汉双解词典(内文排版).zip");

        String md5 = calcMD5(file);

        long endTime = System.currentTimeMillis();

        System.out.println("MD5:" + md5 + "\n 耗时:" + ((endTime - beginTime) / 1000) + "s");

    }

    /**

     * 计算文件 MD5

     * @param file

     * @return 返回文件的md5字符串，如果计算过程中任务的状态变为取消或暂停，返回null， 如果有其他异常，返回空字符串

     */

    protected static String calcMD5(File file) {

        try (InputStream stream = Files.newInputStream(file.toPath(), StandardOpenOption.READ)) {

            MessageDigest digest = MessageDigest.getInstance("MD5");

            byte[] buf = new byte[8192];

            int len;

            while ((len = stream.read(buf)) > 0) {

                digest.update(buf, 0, len);

            }

            return toHexString(digest.digest());

        } catch (IOException e) {

            e.printStackTrace();

            return "";

        } catch (NoSuchAlgorithmException e) {

            e.printStackTrace();

            return "";

        }

    }

    public static String toHexString(byte[] data) {

          StringBuilder r = new StringBuilder(data.length * 2);

          for (byte b : data) {

              r.append(hexCode[(b >> 4) & 0xF]);

              r.append(hexCode[(b & 0xF)]);

          }

          return r.toString();

      }

}