获取文件MD5值 JAVA代码

                package com.topcheer;


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;
public class GetFileMD5 {
/**
 * 获取压缩文件MD5值
 * David 2012-10-12 
 * 
 */
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) {
 
//System.err.println(GetFileMD5.class.getName()+"初始化失败，MessageDigest不支持MD5Util。");
e.printStackTrace();
  }
}


public static String getFileMD5String(File file) throws IOException{
   FileInputStream in = new FileInputStream(file);
   FileChannel ch =in.getChannel();
   MappedByteBuffer byteBuffer =ch.map(FileChannel.MapMode.READ_ONLY, 0, file.length());
  messagedigest.update(byteBuffer);
   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, 0,bytes.length);
}


private static String bufferToHex(byte bytes[], int m, int n){
   StringBuffer stringbuffer =new StringBuffer(2 * n);
   int k = m + n;
   for (int l = m; l< k; 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);
}


//
public static void main(String[] args) throws IOException{
   long beginTime =System.currentTimeMillis();
   File fileZIP = new File("D:/TEST/IMG_0004.zip");
   String md5=getFileMD5String(fileZIP);
   long endTime =System.currentTimeMillis();
  System.out.println("md5:"+md5+"\n time:"+((endTime-beginTime)/1000)+"s");
}
}           

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