import java.security.MessageDigest;

public class StringUtil {
    public StringUtil() {
        super();
    }
    
    public static String str;
            public static final String EMPTY_STRING = "";
            private final static String[] hexDigits = { "0", "1", "2", "3", "4", "5",
                            "6", "7", "8", "9", "A", "B", "C", "D", "E", "F" };

            private static String byteToHexString(byte b) {
                    int n = b;
                    if (n < 0)
                            n = 256 + n;
                    int d1 = n / 16;
                    int d2 = n % 16;
                    return hexDigits[d1] + hexDigits[d2];
            }

            /**
             * 转换字节数组为16进制字串
             * @param b 字节数组
             * @return 16进制字串
             */
            public static String byteArrayToHexString(byte[] b) {
                    StringBuffer resultSb = new StringBuffer();
                    for (int i = 0; i < b.length; i++) {
                            resultSb.append(byteToHexString(b[i]));
                    }
                    return resultSb.toString();
            }

            public static String MD5Encode(String origin) {
                    String resultString = null;
                    try {
                            resultString = new String(origin);
                            MessageDigest md = MessageDigest.getInstance("MD5");
                            resultString = byteArrayToHexString(md.digest(resultString
                                            .getBytes()));
                    } catch (Exception ex) {
                    }
                    return resultString;
            }
}