一点关于MD5计算的封装

baobaoupup

浏览: 470866 次

最近访客更多访客>>

u012363178

shang226

lord_is_layuping

pangfei2001

博主相关

博客

微博

相册

留言

关于我

文章分类

全部博客 (853)

社区版块

存档分类

本文参考：http://snowolf.iteye.com/blog/379860

MD5 是message-digest algorithm 5 （信息-摘要算法）缩写，广泛用于加密和解密技术，常用于文件校验。校验？MD5是用于对信息生成信息摘要（即散列码）的算法之一。不管文件多大，经过MD5后都能生成唯一的MD5值。好比现在的ISO校验，都是MD5校验。怎么用？当然是把ISO经过MD5后产生MD5的值。一般下载linux-ISO的朋友都见过下载链接旁边放着MD5的串。就是用来验证文件是否一致的。关于信息摘要和散列码请参照《<a title="阅读全文" target="_blank" href="http://hubingforever.blog.163.com/blog/static/17104057920118981219705/" style="color:rgb(245,149,19); line-height:25px; text-decoration:initial; font-family:Arial,Helvetica,simsun,u5b8bu4f53; font-size:14px; background-color:rgb(245,245,245); white-space:nowrap">数字证书简介</a>》 <div style="line-height:25px; font-family:Arial,Helvetica,simsun,u5b8bu4f53; font-size:14px; background-color:rgb(245,245,245)"> 关于MD5用于验证文件发放和收方是否一致的大概流程如图1所示 </div> <div style="line-height:25px; font-family:Arial,Helvetica,simsun,u5b8bu4f53; font-size:14px; background-color:rgb(245,245,245)"> 图1 <div> <div><img alt="一个计算MD5的工具类 - hubingforever - 民主与科学" src="http://img.my.csdn.net/uploads/201212/23/1356265406_5700.jpg" width="517" height="389" style="border:0px; max-width:100%; margin:0px 10px 0px 0px"></div> 以下是对于MD5计算的一个简单包装类</div> </div> <div style="line-height:25px; font-family:Arial,Helvetica,simsun,u5b8bu4f53; font-size:14px; background-color:rgb(245,245,245)"> MD5Util.java文件</div> <div style="line-height:25px; font-family:Arial,Helvetica,simsun,u5b8bu4f53; font-size:14px; background-color:rgb(245,245,245)"> <pre class="prettyprint" style="padding:2px; border:1px solid rgb(136,136,136)"><div> package edu.edut.robin.utils; </div><div> </div><div> import java.io.File; </div><div> import java.io.FileInputStream; </div><div> import java.io.IOException; </div><div> import java.io.InputStream; </div><div> import java.io.UnsupportedEncodingException; </div><div> </div><div> import java.security.MessageDigest; </div><div> import android.util.Log; </div><div> </div><div> public class MD5Util </div><div>{</div><div> </div><div> private static String encodingAlgorithm="MD5"; </div><div> </div><div> public final static byte[] md5sum(byte[] data) { </div><div> if(data == null || data.length == 0){ </div><div> return null; </div><div> } </div><div> try { </div><div> MessageDigest mdTemp = MessageDigest.getInstance(encodingAlgorithm); </div><div> mdTemp.update(data); </div><div> return mdTemp.digest(); </div><div> </div><div> } catch (Exception e) { </div><div> </div><div> } </div><div> </div><div> return null; </div><div> } </div><div> </div><div> static String convertToHexString(byte data[]) { </div><div> StringBuffer strBuffer = new StringBuffer(); </div><div> for (int i = 0; i < data.length; i++) { </div><div> strBuffer.append(Integer.toHexString(0xff & data[i])); </div><div> } </div><div> return strBuffer.toString(); </div><div> } </div><div> public static byte[] md5sum(File file) { </div><div> InputStream fis = null; </div><div> byte[] buffer = new byte[1024]; </div><div> int numRead = 0; </div><div> MessageDigest md5; </div><div> try{ </div><div> fis = new FileInputStream(file); </div><div> md5 = MessageDigest.getInstance(encodingAlgorithm); </div><div> while((numRead=fis.read(buffer)) > 0) { </div><div> md5.update(buffer,0,numRead); </div><div> } </div><div> return md5.digest(); </div><div> } catch (Exception e) { </div><div> e.printStackTrace(); </div><div> return null; </div><div> } finally{ </div><div> if(fis != null){ </div><div> try { </div><div> fis.close(); </div><div> } catch (IOException e) { </div><div> e.printStackTrace(); </div><div> } </div><div> } </div><div> } </div><div> } </div><div>}</div></pre> </div> <div style="line-height:25px; font-family:Arial,Helvetica,simsun,u5b8bu4f53; font-size:14px; background-color:rgb(245,245,245)"> 关于MessageDigest的更多内容请参考《<a title="阅读全文" target="_blank" href="http://hubingforever.blog.163.com/blog/static/171040579201210781650340/" style="color:rgb(245,149,19); text-decoration:initial; white-space:nowrap">MessageDigest简介</a><a title="阅读全文" target="_blank" href="http://hubingforever.blog.163.com/blog/static/171040579201210781650340/" style="color:rgb(245,149,19); text-decoration:initial; white-space:nowrap">》</a> </div> <div style="line-height:25px; font-family:Arial,Helvetica,simsun,u5b8bu4f53; font-size:14px; background-color:rgb(245,245,245)"> 结束</div>

分享到：