md5加密工具类

package cn.rx.oamp.util;
import java.security.MessageDigest;
import java.util.Date;

/**
 * 采用MD5生成32位字符串
 * @author zhongyao
 * @version 2010年12月27日18:02:06
 *
 */
public class RxMD5 {
	
	private static final  RxMD5 rxmd5 = new RxMD5();
	
	private static int seed = 1;
	
	private RxMD5(){
		
	}
	
	public static  RxMD5 getInstance(){
		return rxmd5;
	}
	
	/**
	 * 对字符串采用MD5加密
	 * @param s
	 * @return
	 */
	public final String md5(String s) {
		char hexDigits[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
				'a', 'b', 'c', 'd', 'e', 'f' };
		try {
			byte[] strTemp = s.getBytes();
			MessageDigest mdTemp = MessageDigest.getInstance("MD5");
			mdTemp.update(strTemp);
			byte[] md = mdTemp.digest();
			int j = md.length;
			char str[] = new char[j * 2];
			int k = 0;
			for (int i = 0; i < j; i++) {
				byte byte0 = md[i];
				str[k++] = hexDigits[byte0 >>> 4 & 0xf];
				str[k++] = hexDigits[byte0 & 0xf];
			}
			return new String(str);
		} catch (Exception e) {
			return null;
		}
	}

}