获取URL相关信息

import java.net.URL;
import java.net.URLConnection;
import java.net.ConnectException;
import java.io.IOException;
import java.util.Date;
import java.net.HttpURLConnection;

public class GetURLInfo{
    public static void printInfo(URL url){
        System.out.println("==================URL info==================");
        //URL基本信息
        System.out.println("File ["+url.getFile()+"]");
        System.out.println("Protocol ["+url.getProtocol()+"]");
        System.out.println("Authority ["+url.getAuthority()+"]");
        System.out.println("DefaultPort ["+url.getDefaultPort()+"]");
        System.out.println("Host ["+url.getHost()+"]");
        System.out.println("Path ["+url.getPath()+"]");
        System.out.println("Port ["+url.getPort()+"]");
        System.out.println("Query ["+url.getQuery()+"]");
        System.out.println("Ref ["+url.getRef()+"]");
        System.out.println("UserInfo ["+url.getUserInfo()+"]");
        
        URLConnection c = null;
        try{
            c = url.openConnection();
            System.out.println("==================URLConnection info==================");
            //显示信息
            System.out.println("ContentType [" + c.getContentType() + "]");
            System.out.println("ContentEncoding [" + c.getContentEncoding() + "]");
            System.out.println("Content [" + c.getContent() + "]");
            System.out.println("ContentLength [" + c.getContentLength() + "]");
            System.out.println("Date [" + new Date(c.getDate()) + "]");
            System.out.println("LastModified [" + new Date(c.getExpiration()) + "]");
            System.out.println("Expiration [" + new Date(c.getLastModified()) + "]");
        
            if(c instanceof HttpURLConnection){
                System.out.println("==================HttpURLConnection info==================");
                HttpURLConnection httpURL = (HttpURLConnection)c;
                System.out.println("RequestMethod [" + httpURL.getRequestMethod() + "]");
                System.out.println("ResponseMessage [" + httpURL.getResponseMessage() + "]");
                System.out.println("ResponseCode [" + httpURL.getResponseCode() + "]");
                }
            }catch(IOException e){
            e.printStackTrace();
            }
        }
        
    public static void main(String[] args){
        try{
            String urlStr = "http://www.sina.com.cn:80/index.html";
            URL url = new URL(urlStr);
            printInfo(url);
        }catch(Exception e){
            System.err.println(e);
            }
        }
    }

运行结果：

G:\maul keyboard\network programming>javac GetURLInfo.java

G:\maul keyboard\network programming>java GetURLInfo
==================URL info==================
File [/index.html]
Protocol [http]
Authority [www.sina.com.cn:80]
DefaultPort [80]
Host [www.sina.com.cn]
Path [/index.html]
Port [80]
Query [null]
Ref [null]
UserInfo [null]
==================URLConnection info==================
ContentType [text/html]
ContentEncoding [null]
Content [sun.net.www.protocol.http.HttpURLConnection$HttpInputStream@6178b9ce]
ContentLength [21826]
Date [Sat Sep 08 18:29:00 GMT+08:00 2018]
LastModified [Sat Sep 08 18:28:54 GMT+08:00 2018]
Expiration [Wed Apr 27 10:00:04 GMT+08:00 2005]
==================HttpURLConnection info==================
RequestMethod [GET]
ResponseMessage [OK]
ResponseCode [200]

G:\maul keyboard\network programming>