java安全机制——MD5加密算法

public class MD5Utils {
/**
 * 使用md5的算法进行加密
 */
public static String md5(String plainText) {
byte[] secretBytes = null;
try {
secretBytes = MessageDigest.getInstance("md5").digest(
                    plainText.getBytes());
        } catch (NoSuchAlgorithmException e) {
            throw new RuntimeException("没有md5这个算法！");
        }
        String md5code = new BigInteger(1, secretBytes).toString(16);
        for (int i = 0; i < 32 - md5code.length(); i++) {
            md5code = "0" + md5code;
        }
        return md5code;
    }

}