到老外的網站找到的！修改了一下！
import java.security.MessageDigest;
public class MD5
... {
private MessageDigest md5;
private static MD5 Instance;
public synchronized static MD5 getMD5Instance()
...{
if(Instance==null)
Instance=new MD5();
return Instance;
}
private MD5()
...{
try...{
this.md5 = MessageDigest.getInstance("MD5");
}
catch (Exception e)
...{
System.out.println(e.toString());
e.printStackTrace();
}
}
public String compute(String inStr)
...{
// convert input String to a char[]
// convert that char[] to byte[]
// get the md5 digest as byte[]
// bit-wise AND that byte[] with 0xff
// prepend "0" to the output StringBuffer to make sure that we don't end up with
// something like "e21ff" instead of "e201ff"
char[] charArray = inStr.toCharArray();
byte[] byteArray = new byte[charArray.length];
for (int i=0; i<charArray.length; i++)
byteArray[i] = (byte) charArray[i];
byte[] md5Bytes = this.md5.digest(byteArray);
StringBuffer hexValue = new StringBuffer();
for (int i=0; i<md5Bytes.length; i++)
...{
int val = ((int) md5Bytes[i] ) & 0xff;
if (val < 16) hexValue.append("0");
hexValue.append(Integer.toHexString(val));
}
return hexValue.toString();
}
public static void main(String[] args)
...{
System.out.println(MD5.getMD5Instance().compute("").toUpperCase());
}
}