code: public static UserAgent parse(String userAgentString) {
  		final UserAgent userAgent = new UserAgent();
  		
  		final Browser browser = parseBrowser(userAgentString);
  		userAgent.setBrowser(parseBrowser(userAgentString));
  		userAgent.setVersion(browser.getVersion(userAgentString));
  		
  		final Engine engine = parseEngine(userAgentString);
  		userAgent.setEngine(engine);
  		if (false == engine.isUnknown()) {
  			userAgent.setEngineVersion(parseEngineVersion(engine, userAgentString));
  		}
  		userAgent.setOs(parseOS(userAgentString));
  		final Platform platform = parsePlatform(userAgentString);
  		userAgent.setPlatform(platform);
  		userAgent.setMobile(platform.isMobile() || browser.isMobile());
  		
  
  		return userAgent;
  	}
docs: 解析User-Agent
  
  @param userAgentString User-Agent字符串
  @return {@link UserAgent}