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[Java教程]利用 filter 机制 给 静态资源 url 加上时间戳,来防止js和css文件的缓存,利于开发调试


直接上代码:

public class WeiXinFilter implements Filter{	private static Logger logger = LoggerFactory.getLogger(WeiXinFilter.class);	public void init(FilterConfig fConfig) throws ServletException {}	public void destroy() {}	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {		HttpServletRequest req = (HttpServletRequest)request;		HttpServletResponse resp = (HttpServletResponse)response;				String requestURL = req.getRequestURL().toString();		String queryStr = req.getQueryString();				// add timestamp to static resource, to avoid cache		if(requestURL != null && (requestURL.endsWith(".js") || requestURL.endsWith(".css"))){	// static resource			String newURL = null;			if(StringUtils.isNotBlank(queryStr) && queryStr.trim().indexOf(ParameterConfig.STATIC_TAIL) == -1){				newURL = requestURL + "?" + queryStr + "&" + ParameterConfig.STATIC_TAIL + new Date().getTime();				resp.sendRedirect(newURL);//				req.getRequestDispatcher(newURL).forward(request, response);				return;			}			if(StringUtils.isBlank(queryStr)){				newURL = requestURL + "?" + ParameterConfig.STATIC_TAIL + new Date().getTime();				resp.sendRedirect(newURL);//				req.getRequestDispatcher(newURL).forward(request, response);				return;			}						try{				chain.doFilter(request, response);			}catch(Exception e){				logger.error(e.toString());			}			return;		}

public class ParameterConfig {		/** 静态资源 为防止缓存,加上时间戳标志 */	public static final String STATIC_TAIL = "__oawx_t=";

  

配置下过滤器就行了,效果如下:

在开发阶段还是比较有用的。