import java.security.MessageDigest;public class MD5Utils {/*** MD5加码 生成32位md5码      */public static String string2MD5(String inStr) {MessageDigest md5 = null;try {md5 = MessageDigest.getInstance("MD5");} catch (Exception e) {System.out.println(e.toString());e.printStackTrace();return "";}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 = 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();}/*** 加密解密算法 执行一次加密，两次解密 */public static String convertMD5(String inStr) {char[] a = inStr.toCharArray();for (int i = 0; i < a.length; i++) {a[i] = (char) (a[i] ^ 't');}String s = new String(a);return s;}// 测试主函数  public static void main(String args[]) {String s = "666666";System.out.println("原始：" + s);System.out.println("MD5后：" + string2MD5(s));System.out.println("加密的：" + convertMD5(s));System.out.println("解密的：" + convertMD5(convertMD5(s)));}
}

 运行结果截图：