通过filter实现对输出内容的压缩处理
在实际当中大量的js和页面内容使得页面呈现要花很长时间，特别是使用ext。如是找到这种办法去处理一下，还没有测试有多大的优化性能。全部实现代码在附件中
public class CompressionFilter implements Filter {// 适合在上JBoss, Jetty, JOnAS, OC4J, Orion,and Tomcat,其它的可能有bugstatic boolean useFilter = true;public static final String ENCODING = "UTF-8";private static final String _GZIP = "gzip";private static final String _ALREADY_FILTERED = CompressionFilter.class.getName() + "_ALREADY_FILTERED";private static final String _COMPRESS = "compress";public static String[] BOOLEANS = {"true", "t", "y", "on", "1"};private static Log _log = LogFactory.getLog(CompressionFilter.class);public void init(FilterConfig config) {}public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain)throws IOException, ServletException {if (_log.isDebugEnabled()) {if (useFilter) {_log.debug("Compression is enabled");}else {_log.debug("Compression is disabled");}}HttpServletRequest httpReq = (HttpServletRequest)req;HttpServletResponse httpRes = (HttpServletResponse)res;String completeURL = httpReq.getRequestURL().toString();if (useFilter && isCompress(httpReq) && !isInclude(httpReq) &&acceptsGzip(httpReq) && !isAlreadyFiltered(httpReq)) {if (_log.isDebugEnabled()) {_log.debug("Compressing " + completeURL);}httpReq.setAttribute(_ALREADY_FILTERED, Boolean.TRUE);CompressionResponse compressionResponse =new CompressionResponse(httpRes);chain.doFilter(req, compressionResponse);compressionResponse.finishResponse();}else {if (_log.isDebugEnabled()) {_log.debug("Not compressing " + completeURL);}chain.doFilter(req, res);}}public void destroy() {}protected boolean isAlreadyFiltered(HttpServletRequest req) {if (req.getAttribute(_ALREADY_FILTERED) != null) {return true;}else {return false;}}protected boolean isCompress(HttpServletRequest req) {if (!getBoolean(req.getParameter(_COMPRESS), true)) {return false;}else {return true;}}protected boolean isInclude(HttpServletRequest req) {String uri = (String)req.getAttribute("javax.servlet.include.request_uri");if (uri == null) {return false;}else {return true;}}protected boolean acceptsGzip(HttpServletRequest req) {String acceptEncoding = req.getHeader("Accept-Encoding");if ((acceptEncoding != null) &&(acceptEncoding.indexOf(_GZIP) != -1)) {return true;}else {return false;}}protected boolean getBoolean(String value, boolean defaultValue) {if (value != null) {try {value = value.trim();if (value.equalsIgnoreCase(BOOLEANS[0]) ||value.equalsIgnoreCase(BOOLEANS[1]) ||value.equalsIgnoreCase(BOOLEANS[2]) ||value.equalsIgnoreCase(BOOLEANS[3]) ||value.equalsIgnoreCase(BOOLEANS[4])) {return true;}else {return false;}}catch (Exception e) {}}return defaultValue;}} 1 楼 sadfasfasd 2008-03-02 兄弟，你的头像是哪部电影？ 我想看看 2 楼 jasongreen 2008-03-05 我也想看看