（1）什么话都不说，意思很简单 就是实现页面的压缩后发送！据说对于篇幅比较长的页面可以提高几百倍哦！
（2）注意事项：并不是所有的游览器都支持压缩页面的发送与接收，所以要用代码来检验，如果可以则发送不可以
则按照正常的发送；
（即是：在HTTP包头中检查 Accept-Encoding报头，检查他手否包含有关gzip的项，如果支持，它使用PrintWriter封
装GZIPOutputStream，不支持的话则正常发送页面，同时加上了一个功能 禁止页面压缩！）
（3）显示页面的servlet
package com.lc.ch04Gzip;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class LongServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out;
if (GzipUtilities.isGzipSupported(request)
&& !GzipUtilities.isGzipDisabled(request)) {
out = GzipUtilities.getGzipWriter(response);
response.setHeader("Content-Encoding", "gzip");
} else {
out = response.getWriter();
}
String docType = "<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.0 "
+ "Transitional//EN\">\n";
String title = "Long Page";
out.println(docType + "<HTML>\n" + "<HEAD><TITLE>" + title
+ "</TITLE></HEAD>\n" + "<BODY BGCOLOR=\"#FDF5E6\">\n"
+ "<H1 ALIGN=\"CENTER\">" + title + "</H1>\n");
String line = "Bfsdfdsfdsflah, blfsdfdsfah, blasfdsdfh, blsdfdsfah, bldfsdfsdfah. "
+ "Yaddsfdsdfa, ysfdsdfadda, yadsdfsdfdsda, yasdfsdfdsfdda.";
for (int i = 0; i < 10000; i++) {
out.println(line);
}
out.println("</BODY></HTML>");
out.close(); // Needed for gzip; optional otherwise.
}
}
（4）处理压缩的类
package com.lc.ch04Gzip;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.zip.GZIPOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class GzipUtilities {
public static boolean isGzipSupported
(HttpServletRequest request) {
String encodings = request.getHeader("Accept-Encoding");
return((encodings != null) &&
(encodings.indexOf("gzip") != -1));
}
public static boolean isGzipDisabled
(HttpServletRequest request) {
String flag = request.getParameter("disableGzip");
return((flag != null) && (!flag.equalsIgnoreCase("false")));
}
public static PrintWriter getGzipWriter
(HttpServletResponse response) throws IOException {
return(new PrintWriter
(new GZIPOutputStream
(response.getOutputStream())));
}
}
（5）演示效果：（效果很好 不过没有对比 不过应该可以 一般的图片 不需要压缩了！）
ok！
时间： 2024-10-25 12:45:12