上一篇介绍了MD5加密算法，之前写的代码有些冗余，而且可读性很差。今天把对文本数据的加密，以及获取文件的md5值做一个封装类。代码如下：

package com.itydl.utils;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.IOException;

import java.security.MessageDigest;

import java.security.NoSuchAlgorithmException;

public class Md5Utils {

	/**

	 * @param path

	 *    文件的路径

	 * @return

	 *    文件的MD5值

	 */

	public static String getFileMD5(String path){

		StringBuilder mess = new StringBuilder();

		try {

			FileInputStream fis = new FileInputStream(new File(path));

			//获取MD5加密器

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

			byte[] buffer = new byte[10240];

			int len = fis.read(buffer);

			while (len != -1) {

				md.update(buffer, 0, len);

				//继续读取

				len = fis.read(buffer);

			}

			//读完文件，获取文件的md5值，完成获取MD5值。获取的值存储在返回的数组中

			byte[] digest = md.digest();

			for (byte b : digest){

				//把每个字节转成16进制数

				int d = b & 0xff;// 0x000000ff

				String hexString = Integer.toHexString(d);

				if (hexString.length() == 1) {//字节的高4位为0

					hexString = "0" + hexString;

				}

				hexString = hexString.toUpperCase();

				mess.append(hexString);//把每个字节对应的2位十六进制数当成字符串拼接一起

			}

		} catch (NoSuchAlgorithmException e) {

			// TODO Auto-generated catch block

			e.printStackTrace();

		} catch (FileNotFoundException e) {

			// TODO Auto-generated catch block

			e.printStackTrace();

		} catch (IOException e) {

			// TODO Auto-generated catch block

			e.printStackTrace();

		}

		return mess + "";

	}

	public static String md5(String str){

		StringBuilder mess = new StringBuilder();

		try {

			//获取MD5加密器

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

			byte[] bytes = str.getBytes();

			byte[] digest = md.digest(bytes);

			for (byte b : digest){

				//把每个字节转成16进制数

				int d = b & 0xff;// 0x000000ff

				String hexString = Integer.toHexString(d);

				if (hexString.length() == 1) {//字节的高4位为0

					hexString = "0" + hexString;

				}

				mess.append(hexString);//把每个字节对应的2位十六进制数当成字符串拼接一起

			}

		} catch (NoSuchAlgorithmException e) {

			// TODO Auto-generated catch block

			e.printStackTrace();

		}

		return mess + "";

	}

}