設定tomcat啟用GZIP壓縮注意事項

原理簡介

配置方法

1. <Connectorport="80"protocol="HTTP/1.1"
2.            connectionTimeout="20000"
3.            redirectPort="8443"executor="tomcatThreadPool"URIEncoding="utf-8"
4.                        compression="on"
5.                        compressionMinSize="50"noCompressionUserAgents="gozilla, traviata"
6.                        compressableMimeType
   ="text/html,text/xml,text/javascript,text/css,text/plain"/>

• compression="on" 開啟壓縮功能 
• compressionMinSize="50" 啟用壓縮的輸出內容大小，預設為2KB 
• noCompressionUserAgents="gozilla, traviata" 對於以下的瀏覽器，不啟用壓縮 
• compressableMimeType="text/html,text/xml,text/javascript,text/css,text/plain"　哪些資源型別需要壓縮

測試方法

1.通過瀏覽器訪問抓包看是否有gzip欄位，資料量是否減少（firebug

2.通過httpclient程式模擬

package com.annotation.test;

import org.apache.commons.httpclient.HttpClient;

import org.apache.commons.httpclient.HttpStatus;

public class TestGzip {

	private final static String url = "http://192.168.14.216/demo/test2";

	public static void main(String[] args) throws Exception {

		HttpClient http = new HttpClient();

		CustomGetMethod get = new CustomGetMethod(url);

		// 新增頭資訊告訴服務端可以對Response進行GZip壓縮
		get.setRequestHeader("Accept-Encoding", "gzip,deflate");
		get.setRequestHeader("Header","{\"version\":\"1.0.0\",\"clienttype\":\"3\"}");
		get.setRequestHeader("accept", "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8");
		try {
			int statusCode = http.executeMethod(get);

			if (statusCode != HttpStatus.SC_OK) {

				System.err.println("Method failed: "

				+ get.getStatusLine());

			}
			// 列印解壓後的返回資訊
			String after  = get.getResponseBodyAsString();
			System.out.println(after+"|size="+after.getBytes().length);

		} catch (Exception e) {

			System.err.println("頁面無法訪問");

			e.printStackTrace();

		} finally {

			get.releaseConnection();

		}
	}
}

package com.annotation.test;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.zip.GZIPInputStream;
import org.apache.commons.httpclient.Header;
import org.apache.commons.httpclient.methods.GetMethod;
public class CustomGetMethod extends GetMethod {
	public CustomGetMethod(String uri) {
		super(uri);
	}
	public String getResponseBodyAsString() throws IOException {
		GZIPInputStream gzin;
		String before = super.getResponseBodyAsString();
		System.out.println(before+"|size="+before.getBytes().length);	
		Header[] headers = getResponseHeaders();
		for(Header header:headers){
			System.out.println(header.getName()+"|"+header.getValue());
		}
		if (getResponseBody() != null || getResponseStream() != null) {
			if (getResponseHeader("Content-Encoding") != null&& getResponseHeader("Content-Encoding").getValue().toLowerCase().indexOf("gzip") > -1) {
				// For GZip response
				InputStream is = getResponseBodyAsStream();
				gzin = new GZIPInputStream(is);
				InputStreamReader isr = new InputStreamReader(gzin);
				java.io.BufferedReader br = new java.io.BufferedReader(isr);
				StringBuffer sb = new StringBuffer();
				String tempbf;
				while ((tempbf = br.readLine()) != null) {
					sb.append(tempbf);
					sb.append("\r\n");
				}
				isr.close();
				gzin.close();
				return sb.toString();
			} else {
				// For deflate response
				return super.getResponseBodyAsString();
			}
		} else {
			return null;
		}
	}
}

注意事項