java的md5加密算法代码

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;public final class Md5Util {private static final char hexDigits[] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c','d', 'e', 'f'};public static String encode(File file) {FileInputStream in = null;MessageDigest md5 = null;try {in = new FileInputStream(file);FileChannel ch = in.getChannel();MappedByteBuffer byteBuffer = ch.map(FileChannel.MapMode.READ_ONLY, 0, file.length());md5 = MessageDigest.getInstance("MD5");md5.update(byteBuffer);} catch (Exception e) {e.printStackTrace();} finally {try {in.close();} catch (IOException e) {e.printStackTrace();}}return toHex(md5.digest());}public static String encode(String arg) {if (arg == null) {arg = "";}MessageDigest md5 = null;try {md5 = MessageDigest.getInstance("MD5");md5.update(arg.getBytes("UTF-8"));} catch (Exception e) {e.printStackTrace();}return toHex(md5.digest());}private static String toHex(byte[] bytes) {StringBuffer str = new StringBuffer(32);for (byte b : bytes) {str.append(hexDigits[(b & 0xf0) >> 4]);str.append(hexDigits[(b & 0x0f)]);}return str.toString();}}