GzipFiter过滤器提升网站性能.docVIP

package cn.test.web.filter; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.OutputStream; import java.io.OutputStreamWriter; import java.io.PrintWriter; import java.util.zip.GZIPOutputStream; import javax.servlet.Filter; import javax.servlet.FilterChain; import javax.servlet.FilterConfig; import javax.servlet.ServletException; import javax.servlet.ServletOutputStream; import javax.servlet.ServletRequest; import javax.servlet.ServletResponse; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpServletResponseWrapper; /* * 实现压缩数据，再响应给浏览器；以提高网站性能; */ public class GzipFilter implements Filter { @Override public void init(FilterConfig filterConfig) throws ServletException { } @Override public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws IOException, ServletException { HttpServletRequest request = (HttpServletRequest) req; HttpServletResponse response = (HttpServletResponse) resp; // response.getOutputStream().write()是把数据写入到浏览器； // 为了把数据拦截下来，实现压缩，需要重新复写response.getOutputStream()代表的类ServletOutputStream及response.getOutputStream().write方法 // 实现把数据写入到内存中去;同样，我们还需要复写response.getWriter代表的类PrintWriter及write方法 BufferResponse buffResponse = new BufferResponse(response); chain.doFilter(request, buffResponse); // 然后把内存中的数据压缩后响应给浏览器 byte[] buff = buffResponse.getBuffer(); System.out.println(原始大小 + buff.length); // 把数据压缩后写入bout ByteArrayOutputStream bout = new ByteArrayOutputStream(); GZIPOutputStream gout = new GZIPOutputStream(bout); gout.write(buff); gout.close();//关闭，刷新流 byte gzip[] = bout.toByteArray(); System.out.println(压缩后的大小 + gzip.length); // 设置压缩头及压缩长度 response.setHeader(content-encoding, gzip); response.setContentLength(gzip.length); /