MD5加密及随机数生成

    今天贴两个简单的方法，需要的时候不用自己再写，
 

	public static string md5(string plaintext){		messagedigest m;		try {			m = messagedigest.getinstance("md5");			m.reset(); 			m.update(plaintext.getbytes()); 			byte[] digest = m.digest(); 			biginteger bigint = new biginteger(1,digest); 			string hashtext = bigint.tostring(16); 			// now we need to zero pad it if you actually want the full 32 chars. 			while(hashtext.length() < 32 ){ 			  hashtext = "0"+hashtext; 			} 			return hashtext;		} catch (nosuchalgorithmexception e) {			e.printstacktrace();			return system.currenttimemillis() + "";		} 	}	public static string randomcreator(int num){		random random = new random();		int i=random.nextint();		i=math.abs(i);				string tem=string.valueof(i);		while(tem.length()<num){			tem+="0";		}		return tem.substring(0,num);	}