字符串转MD5

	public static String getMD5(String url){
		String result="";
		try {
			MessageDigest md=MessageDigest.getInstance("MD5");
			md.update(url.getBytes());
			byte[] bytes=md.digest();
			StringBuilder sb=new StringBuilder();
			for(byte b:bytes){
				String str=Integer.toHexString(b& 0xFF);
				if(str.length()==1){
					sb.append("0");
				}
				sb.append(str);
			}
			result=sb.toString();
		} catch (Exception e) {
			e.printStackTrace();
		}
		return result;
	}