MD5 SHA TestMessageDigest

package zhch.illq;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class TestMessageDigest {

	public static void main(String[] args) {
		System.out.println(Digest.getMd5("admin"));
		System.out.println(Digest.getMd5("zh"));
	}
}

class Digest {
	private static MessageDigest md5Algorithm;

	public static String getMd5(String src) {
		char[] hexDigits = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
		try {
			if (md5Algorithm == null)
				md5Algorithm = MessageDigest.getInstance("MD5");
		} catch (NoSuchAlgorithmException e) {
			e.printStackTrace();
		}
		// 这种方法是错误的,在结果的第一位是0时,0会消失  eg. zh
		// BigInteger number = new BigInteger(1, md5Algorithm.digest(src.getBytes()));
		// return number.toString(16);

		byte[] digestBytes = md5Algorithm.digest(src.getBytes());
		int j = digestBytes.length;
		char str[] = new char[j * 2];
		int k = 0;
		for (int i = 0; i < j; i++) {
			byte byte0 = digestBytes[i];
			str[k++] = hexDigits[byte0 >>> 4 & 0xf];
			str[k++] = hexDigits[byte0 & 0xf];
		}
		return new String(str);
	}

}