java MD5加密类

import java.security.MessageDigest;

import java.security.NoSuchAlgorithmException;

public class Test {
	public static void main(String[] args) {
		Test test = new Test();
		System.out.println(test.encryption("123456"));

	}

	/**  

	 *   

	 * @param plainText  

	 *            明文  

	 * @return 32位密文  

	 */

	public String encryption(String plainText) {

		String re_md5 = new String();

		try {

			MessageDigest md = MessageDigest.getInstance("MD5");

			md.update(plainText.getBytes());

			byte b[] = md.digest();

			int i;

			StringBuffer buf = new StringBuffer("");

			for (int offset = 0; offset < b.length; offset++) {

				i = b[offset];

				if (i < 0)

					i += 256;

				if (i < 16)

					buf.append("0");

				buf.append(Integer.toHexString(i));

			}
			re_md5 = buf.toString();
		} catch (NoSuchAlgorithmException e) {

			e.printStackTrace();

		}

		return re_md5;

	}

}