import java.net.URL; import java.net.URLConnection; import java.io.InputStreamReader; import java.io.BufferedReader; import java.net.HttpURLConnection; /** 客户端仅仅是获取服务端的信息 */ public class HttpClient{ private String urlString; public static void main(String[] args) throws Exception{ if(args.length!=1){ System.out.println("控制台参数错误！"); //终止当前运行的Java虚拟机。 System.exit(1); } HttpClient client = new HttpClient(args[0]); client.run(); } public HttpClient(String url){ this.urlString = url; } private void run() throws Exception{ URL url = new URL(this.urlString); URLConnection conn = url.openConnection(); if(conn instanceof HttpURLConnection){ HttpURLConnection httpConn = (HttpURLConnection)conn; String key; String value; System.out.println("The Headers"); System.out.println("========================================="); for(int i=1;;i++){ if((key=httpConn.getHeaderFieldKey(i))==null){ break; } if((value=httpConn.getHeaderField(i))==null){ break; } System.out.println("key["+key+"]"); System.out.println("value["+value+"]"); } BufferedReader reader = new BufferedReader(new InputStreamReader(httpConn.getInputStream())); String line; System.out.println("Content"); System.out.println("========================================="); while((line=reader.readLine())!=null){ System.out.println(line); } } } } 执行结果： G:maul keyboard etwork programming>java HttpClient http://www.google.cn The Headers ========================================= key[Accept-Ranges] value[none] key[Vary] value[Accept-Encoding] key[Content-Type] value[text/html] key[Date] value[Sat, 10 Nov 2018 10:56:42 GMT] key[Expires] value[Sat, 10 Nov 2018 10:56:42 GMT] key[Cache-Control] value[private, max-age=0] key[Last-Modified] value[Thu, 08 Dec 2016 01:00:57 GMT] key[X-Content-Type-Options] value[nosniff] key[Server] value[sffe] key[X-XSS-Protection] value[1; mode=block] key[Transfer-Encoding] value[chunked] Content ========================================= <!DOCTYPE html> <html lang="zh"> <meta charset="utf-8"> <title>Google</title> <style> html { background: #fff; margin: 0 1em; } body { font: .8125em/1.5 arial, sans-serif; text-align: center; } h1 { font-size: 1.5em; font-weight: normal; margin: 1em 0 0; } p#footer { color: #767676; font-size: .77em; } p#footer a { background: url(//www.google.cn/intl/zh-CN_cn/images/cn_icp.gif) top right no-repeat; padding: 5px 20px 5px 0; } ...