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package com.kaige123.util;
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;
/**
*MD5文字和文件加密<br>
*http://www.
*@author 凯哥
*/
public class MD5Util {
//16进制
protectedstatic char hex[] = {
'0','1', '2', '3', '4', '5', '6','7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
protectedstatic MessageDigest messagedigest = null;
static{
try{
//得到MD5实例
messagedigest= MessageDigest.getInstance("MD5");
}catch (Exception e) {
}
}
//得到文件MD5钥匙
publicstatic String getFileMD5String(File file) throws IOException {
FileInputStreamin = new FileInputStream(file);
FileChannelch = in.getChannel();
MappedByteBufferbyteBuffer =
ch.map(FileChannel.MapMode.READ_ONLY,0,
file.length());
messagedigest.update(byteBuffer);
returnbufferToHex(messagedigest.digest());
}
//得到MD5字符串钥匙
publicstatic String getMD5String(String s) {
returngetMD5String(s.getBytes());
}
publicstatic String getMD5String(byte[] bytes) {
messagedigest.update(bytes);
returnbufferToHex(messagedigest.digest());
}
privatestatic String bufferToHex(byte bytes[]) {
returnbufferToHex(bytes, 0, bytes.length);
}
privatestatic String bufferToHex(byte bytes[], int m, int n) {
StringBufferstringbuffer = new StringBuffer(2 * n);
intk = m + n;
for(int l = m; l < k; l++) {
appendHexPair(bytes[l],stringbuffer);
}
returnstringbuffer.toString();
}
privatestatic void appendHexPair(byte bt, StringBuffer stringbuffer) {
charc0 = hex[(bt & 0xf0) >> 4];
charc1 = hex[bt & 0xf];
stringbuffer.append(c0);
stringbuffer.append(c1);
}
}
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