StringHelper

public class StringHelper {
  public final static String TAG = "StringHelper";
	private static char[] hexDigits = { '0', '1', '2', '3', '4', '5', '6', '7',
			'8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
	/**
	* @Title: jsonNullToEmpty
	* @Description: json解析结果的null转成空字符
	* @param str
	* @return String
	*/
	public static String jsonNullToEmpty(String str) {
		if (TextUtils.isEmpty(str)) {
			return "";
		}
		if ("null".equalsIgnoreCase(str)) {
			return "";
		} else {
			return str;
		}
	}
	/**
	* @Title: isEmail
	* @Description: 是否是有效的email地址
	* @param email
	* @return boolean
	*/
	public static boolean isEmail(String email) {
		Pattern p = Pattern.compile("^[a-zA-Z0-9][\\w\\.-]*[a-zA-Z0-9]@[a-zA-Z0-9][\\w\\.-]*[a-zA-Z0-9]\\.[a-zA-Z][a-zA-Z\\.]*[a-zA-Z]$");
		Matcher m = p.matcher(email);
		return m.matches();
	}
	
	/**
	* @Title: isMobilePhone
	* @Description: 是否是有效的手机号码
	* @param countryCode
	* @param mobiles
	* @return boolean
	*/
	public static final boolean isMobilePhone(String mobile) {
		if (TextUtils.isEmpty(mobile)) {
			return false;
		}
		if (mobile.startsWith("+86")) {
			mobile = mobile.substring(3);
			
		} else if (mobile.startsWith("+86")) {
			mobile = mobile.substring(2);
		}
		Pattern p = Pattern.compile("^((13[0-9])|(14[0-9])|(15[0-9])|(18[0-9]))\\d{8}$");
		Matcher m = p.matcher(mobile);
		return m.matches();
	}
	
	/**
	* @Title: isUrl
	* @Description: 是否是有效的网址
	* @param url
	* @return boolean
	*/
	public static final boolean isUrl(String url) {
		// ^(http(s)?://)?([\w-]+\\.)+[\\w-]+(/[\\w- ./?%&=]*)?$
		// ^http\://[a-zA-Z0-9\-\.]+\.[a-zA-Z]{2,3}(/\S*)?$
		// ^(http(s)?://)?([\\w-]+\\.)+[\\w-]+(/[\\w-   ./?%&=]*)?$
		Pattern p = Pattern.compile("^(http(s)?://)?([\\w-]+\\.)+[\\w-]+(/[\\w- ./?%&=]*)?$");
		Matcher m = p.matcher(url);
		return m.matches();
	}
	/**
	 * @Title: byte2HexStr
	 * @Description: 字节数组转成16进制串
	 * @param bytes
	 * @return String
	 */
	public static String byte2HexStr(byte[] bytes) {
		if (bytes == null) {
			return "";
		}
		int num = bytes.length;
		char[] chars = new char[num * 2];
		int ch;
		for (int index = 0; index < num; ++index) {
			ch = bytes[index];
//			chars[index * 2] = hexDigits[ch >> 4];
//			chars[index * 2 + 1] = hexDigits[ch & 0xF];
			chars[2 * index] = hexDigits[(ch >> 4) & 0x0f];
			chars[2 * index + 1] = hexDigits[ch & 0x0f];
		}
		return new String(chars);
	}

	/**
	 * @Title: str2HexStr
	 * @Description: 字符串转成16进制字符串
	 * @param str
	 * @return String
	 */
	public static String str2HexStr(String str) {
		if (TextUtils.isEmpty(str)) {
			return str;
		}
		StringBuilder sb = new StringBuilder("");
		byte[] bytes = str.getBytes();
		int bit;
		for (int index = 0; index < bytes.length; ++index) {
			bit = (bytes[index] & 0x0f0) >> 4;
			sb.append(hexDigits[bit]);
			bit = bytes[index] & 0x0f;
			sb.append(hexDigits[bit]);
		}
		return sb.toString();
	}

	/**
	 * @Title: hexStr2Bytes
	 * @Description: 16进制字符串转成字节数组
	 * @param hexStr
	 * @return byte[]
	 */
	public static byte[] hexStr2Bytes(String hexStr) {
		if (TextUtils.isEmpty(hexStr)) {
			return null;
		}
		if (hexStr.length() % 2 != 0) {
			return null;
		}
		hexStr = hexStr.toUpperCase();
		int length = hexStr.length() / 2;
		char[] hexChars = hexStr.toCharArray();
		byte[] bytes = new byte[length];
		for (int index = 0; index < length; ++index) {
			int pos = index * 2;
			bytes[index] = (byte) (toByte(hexChars[pos]) << 4 | toByte(hexChars[pos + 1]));
		}
		return bytes;
	}

	/**
	 * @Title: md5Hash
	 * @Description: md5加密
	 * @param str
	 * @return String
	 */
	public static String md5Hash(String str) {
		String hashValue = str;
		try {
			MessageDigest digest = MessageDigest.getInstance("MD5");
			digest.update(str.getBytes());
			byte[] messageDigest = digest.digest();
			hashValue = byte2HexStr(messageDigest);
		} catch (NoSuchAlgorithmException e) {
			Logger.getInstance(TAG).debug(e.getMessage());
		}
		return hashValue;
	}

	private static byte toByte(char ch) {
		return (byte) "0123456789ABCDEF".indexOf(ch);
	}
	
	/**
	 * 将字符串里边的半角字符转为全角  ,解决textview参差不齐的情况
	 * @Title: toDBC
	 * @Description: TODO
	 * @param input
	 * @return
	 */
	public static String toDBC(String input) {
		char[] c = input.toCharArray();
		for (int i = 0; i < c.length; i++) {
			if (c[i] == 12288) {
				c[i] = (char) 32;
				continue;
			}
			if (c[i] > 65280 && c[i] < 65375)
				c[i] = (char) (c[i] - 65248);
		}
		return new String(c);
	}
	

}