Servlet/Jsp實現發送壓縮Web頁面 Gzip技術

（1）什麼話都不說，意思很簡單 就是實現頁面的壓縮後發送！據說對於篇幅比較長的頁面可以提高幾百倍哦！

（2）注意事項：並不是所有的游覽器都支持壓縮頁面的發送與接收，所以要用代碼來檢驗，如果可以則發送不可以

則按照正常的發送；

（即是：在HTTP包頭中檢查 Accept-Encoding報頭，檢查他手否包含有關gzip的項，如果支持，它使用PrintWriter封

裝GZIPOutputStream，不支持的話則正常發送頁面，同時加上了一個功能 禁止頁面壓縮！）

（3）顯示頁面的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 = "\n";
		String title = "Long Page";
		out.println(docType + "\n" + "\n" + "\n"
				+ "
" + title + "
\n");
		String line = "Bfsdfdsfdsflah, blfsdfdsfah, blasfdsdfh, blsdfdsfah, bldfsdfsdfah. "
				+ "Yaddsfdsdfa, ysfdsdfadda, yadsdfsdfdsda, yasdfsdfdsfdda.";
		for (int i = 0; i < 10000; i++) {
			out.println(line);
		}
		out.println("");
		out.close(); // Needed for gzip; optional otherwise.
	}
}

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())));
  }
}

ok！