加密工具类
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
* http://www.kaige123.com
* @author凯哥
*/
public class
MD5Util {
//16进制
protected static char hex[] = {
'0', '1', '2', '3', '4', '5', '6','7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
protected static MessageDigest messagedigest = null;
static {
try {
//得到MD5实例
messagedigest = MessageDigest.getInstance("MD5");
} catch (Exception e) {
}
}
//得到文件MD5钥匙
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());
}
//得到MD5字符串钥匙
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 = hex[(bt & 0xf0) >> 4];
char c1 = hex[bt & 0xf];
stringbuffer.append(c0);
stringbuffer.append(c1);
}
}
测试类
package
com.kaige123.util;
import
java.io.File;
import
java.io.IOException;
/**
*测试类
* @author凯哥
*/
public class
Test {
public static void main(String[] args) throws IOException {
//得到字符串MD5
String md5str=MD5Util.getMD5String("凯哥是个胖子");
System.out.println(md5str);
//得到文件的MD5
String filemd5str=MD5Util.getFileMD5String(new File("c:/kaige/a.txt"));
System.out.println(filemd5str);
}
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