MD5加密

/**
 * md5 common class<br>
 * MD5.java
 * @author  <br>
 *         2007/11/19 11:51:59
 */
public class MD5 {

	/**
	 * MD5 instance class
	 */
	private static MD5 instance = null;

	// MD5
	private MessageDigest _md5 = null;

	/**
	 * MD5 instance get.
	 * @return MD5 instance
	 */
	public static MD5 getInstance() {
		if (instance == null) {
			instance = new MD5();
		}
		return instance;
	}

	/**
	 * get md5F<br>
	 * MD5.java<br>
	 */
	private MD5() {
		try {
			_md5 = MessageDigest.getInstance("MD5");
		} catch (Exception e) {

		}
	}

	/**
	 * do md5 <br>
	 * @param str
	 *        string<br>
	 * @return md5Str MD5 string<br>
	 */
	public String getMD5Str(String str) {
		char[] charArray = str.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();

		int val = 0;

		for (int i = 0; i < md5Bytes.length; i++) {
			val = ((int) md5Bytes[i]) & 0xff;

			if (val < 16) {
				hexValue.append("0");
			}

			hexValue.append(Integer.toHexString(val));
		}

		return hexValue.toString();
	}
}