客户端HttpClient4处理 Servlet Gzip后的内容

1、服务器端servlet代码：

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {response.setHeader("Cache-Control", "no-cache");response.setContentType("text/html;charset=UTF-8");String str = "中文测试this is a test!";if (isGzipSupport(request)) {// 支持gzipresponse.setHeader("Content-Encoding", "gzip");OutputStream os = response.getOutputStream();GZIPOutputStream gs = new GZIPOutputStream(os);gs.write(str.getBytes("UTF-8"));// 解决中文乱码问题gs.finish();gs.close();os.close();} else {PrintWriter out = response.getWriter();out.write(str);out.flush();out.close();}}/**     * 判断客户端是否要求进行gzip压缩处理     * @param request     * @return     */    private boolean isGzipSupport(HttpServletRequest request) {        String headEncoding = request.getHeader("accept-encoding");        return (headEncoding != null && (headEncoding.indexOf("gzip") != -1));    }

通过判断http的header中accept-encoding 是否为gzip（表明客户端支持gzip解压，服务端可以使用gzip进行数据压缩），对返回的数据进行gzip压缩。

部署后，浏览器上访问可以得到如下内容：

中文测试this is a test!

通过抓包可以发现：

浏览器默认发送的request请求中会携带aeecpt-encoding gzip信息（现代浏览器都支持gzip解压）

2、客户端代码：

package nc.edu.nuc.utils;import java.io.IOException;import java.nio.charset.Charset;import org.apache.http.Header;import org.apache.http.HeaderElement;import org.apache.http.HttpEntity;import org.apache.http.HttpException;import org.apache.http.HttpRequest;import org.apache.http.HttpRequestInterceptor;import org.apache.http.HttpResponse;import org.apache.http.HttpResponseInterceptor;import org.apache.http.HttpStatus;import org.apache.http.client.ClientProtocolException;import org.apache.http.client.HttpClient;import org.apache.http.client.entity.GzipDecompressingEntity;import org.apache.http.client.methods.HttpGet;import org.apache.http.client.methods.HttpPost;import org.apache.http.entity.StringEntity;import org.apache.http.impl.client.CloseableHttpClient;import org.apache.http.impl.client.DefaultHttpClient;import org.apache.http.protocol.HttpContext;import org.apache.http.util.EntityUtils;@SuppressWarnings("deprecation")public class HttpInterceptorUtil {private static DefaultHttpClient httpclient = new DefaultHttpClient();  static {httpclient.addRequestInterceptor(new HttpRequestInterceptor() {public void process(final HttpRequest request, final HttpContext arg1)throws HttpException, IOException {if (!request.containsHeader("Accept-Encoding")) {request.addHeader("Accept-Encoding", "gzip");}}});/*httpclient.addResponseInterceptor(new HttpResponseInterceptor() {             public void process(                     final HttpResponse response,                      final HttpContext context) throws HttpException, IOException {                 HttpEntity entity = response.getEntity();                 Header ceheader = entity.getContentEncoding();                 if (ceheader != null) {                     HeaderElement[] codecs = ceheader.getElements();                     for (int i = 0; i < codecs.length; i++) {                         if (codecs[i].getName().equalsIgnoreCase("gzip")) {                             response.setEntity(                                     new GzipDecompressingEntity(response.getEntity()));                              return;                         }                     }                 }             }                      });  */}public static void main(String...strings) throws ClientProtocolException, IOException {HttpGet httpget = new HttpGet("http://localhost:8080/WebTest/SendAndGzipServlet");                  // Execute HTTP request         System.out.println("executing request " + httpget.getURI());         HttpResponse response = httpclient.execute(httpget);           System.out.println("----------------------------------------");         System.out.println(response.getStatusLine());         System.out.println(response.getLastHeader("Content-Encoding"));         System.out.println(response.getLastHeader("Content-Length"));         System.out.println("----------------------------------------");           HttpEntity entity = response.getEntity();                  if (entity != null) {             String content = EntityUtils.toString(entity);             System.out.println(content);             System.out.println("----------------------------------------");             System.out.println("Uncompressed size: "+content.length());         }           // When HttpClient instance is no longer needed,          // shut down the connection manager to ensure         // immediate deallocation of all system resources         httpclient.getConnectionManager().shutdown();}}

1）httpClient支持拦截器，我们队client添加了request和response两个拦截器，request拦截器目的是在http header中添加content-encoding gzip信息，方便告诉服务端可以使用gzip压缩，客户端支持解压；response拦截器目的是对gzip数据进行解压。

2）如果把response拦截器注释掉，返回的数据就是乱码：

executing request http://localhost:8080/WebTest/SendAndGzipServlet----------------------------------------HTTP/1.1 200 OKContent-Encoding: gzipContent-Length: 46----------------------------------------?