JAVA MD5加密

package com.demo;

import java.security.MessageDigest;

public class MD5Util {

	private static final String ALGORITHM = "MD5";

	private static final char[] HEX_DIGITS = { '0', '1', '2', '3', '4', '5',
			'6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };

	/**
	 * encode string
	 *
	 * @param algorithm
	 * @param str
	 * @return String
	 */
	public static String encode(String algorithm, String str) {
		if (str == null) {
			return null;
		}
		try {
			MessageDigest messageDigest = MessageDigest.getInstance(algorithm);
			messageDigest.update(str.getBytes());
			return getFormattedText(messageDigest.digest());
		} catch (Exception e) {
			throw new RuntimeException(e);
		}

	}

	/**
	 * encode By MD5
	 *
	 * @param str
	 * @return String
	 */
	public static String getStringMD5String(String str) {
		if (str == null) {
			return null;
		}
		try {
			MessageDigest messageDigest = MessageDigest.getInstance(ALGORITHM);
			messageDigest.update(str.getBytes());
			return getFormattedText(messageDigest.digest());
		} catch (Exception e) {
			throw new RuntimeException(e);
		}

	}

	/**
	 * Takes the raw bytes from the digest and formats them correct.
	 *
	 * @param bytes
	 *            the raw bytes from the digest.
	 * @return the formatted bytes.
	 */
	private static String getFormattedText(byte[] bytes) {
		int len = bytes.length;
		StringBuilder buf = new StringBuilder(len * 2);
		// 把密文转换成十六进制的字符串形式
		for (int j = 0; j < len; j++) { 			
			buf.append(HEX_DIGITS[(bytes[j] >> 4) & 0x0f]);
			buf.append(HEX_DIGITS[bytes[j] & 0x0f]);
		}
		return buf.toString();
	}

	public static void main(String[] args) {
		System.out.println(MD5Util.getStringMD5String("123"));
//		System.out.println("111111 MD5  :"
//				+ EncoderHandler.encode("MD5", "111111"));
//		System.out.println("111111 SHA1 :"
//				+ EncoderHandler.encode("SHA1", "111111"));
	}

}