前段时间做自己社区的论坛，在jive的基础上做一个页面显示所有论坛的帖子,可以称之为总版，模拟Forum类的接口做个SuperForum并且实现Cachable，不过因为这个页面刷新量比较大，虽然被Cache了，我还是想办法进行页面的缓存，感觉用jsp产生的html静态内容当缓存,页面访问速度应该有所提高。
首先想到的一种办法,是采用java.net的URLConnection把服务器上的jsp抓过来做缓存,不过我觉得这样做太见外了,自己服务器上的东西,为何要用HTTP去访问.于是想另外一个办法，把jsp的out对象的输出控制到自己希望的地方.比如输出到静态文件,又或者保存成全局的字符串变量.这样的话,浏览就不需要执行jsp,只是浏览该html了.仅仅在数据有更新的时候进行一次update操作,把jsp重新输出为html.
我觉得，浏览事件比数据插入或更新发生的次数多的时候.不妨试试这个办法来提高页面访问速度.
整件事情有点像把jsp当作模板,生成静态的html页面.
将如下代码写入web-xml
www.hot007.com
| <filter> <filter-name>FileCaptureFilter</filter-name> <filter-class>com.junjing.filter.FileCaptureFilter</filter-class> </filter> <filter-mapping> <filter-name>FileCaptureFilter</filter-name> <url-pattern>/latest.jsp</url-pattern> </filter-mapping> |
latest.jsp是我要cache的页面
java源码代码如下
hot007.com
| /** * START File FileCaptureFilter.java */ package com.junjing.filter; import javax.servlet.*; import javax.servlet.http.*; import java.io.*; public class FileCaptureFilter implements Filter { private String protDirPath; public void init(FilterConfig filterConfig) throws ServletException { protDirPath = filterConfig.getServletContext().getRealPath("/"); } public void doFilter(ServletRequest request,ServletResponse response,FilterChain chain) throws IOException, ServletException { String fileName = protDirPath "forum/lastest.html"; PrintWriter out = response.getWriter(); FileCaptureResponseWrapper responseWrapper = new FileCaptureResponseWrapper((HttpServletResponse)response); chain.doFilter(request, responseWrapper); // fill responseWrapper up String html = responseWrapper.toString(); jc567.cn //得到的html页面结果字符串 // responseWrapper.writeFile(fileName); // dump the contents 写成html文件，也可以保存在内存 //responseWrapper.writeResponse( out ); // back to browser //responseWrapper.sendRedirect("lastestThread.jsp"); } public void destroy() {} } /** * END File FileCaptureFilter.java */ /** * START File FileCaptureResponseWrapper.java */ package com.junjing.filter; import javax.servlet.*; import javax.servlet.http.*; import java.io.*; public class FileCaptureResponseWrapper extends HttpServletResponseWrapper { private CharArrayWriter output; public String toString() { return output.toString(); } public FileCaptureResponseWrapper(HttpServletResponse response) { super(response); output = new CharArrayWriter(); } public PrintWriter getWriter() hot007.com { return new PrintWriter(output); } public void writeFile(String fileName) throws IOException { FileWriter fw = new FileWriter(fileName); fw.write( output.toCharArray() ); fw.close(); } public void writeResponse(PrintWriter out) { out.print( output.toCharArray() ); } } /** * END File FileCaptureResponseWrapper.java */ |
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