Java 实例 - 获取 URL 响应头信息

以下实例演示了如何获取指定 URL 的响应头信息：

Main.java 文件

import java.io.IOException;
import java.net.URL;
import java.net.URLConnection;
import java.util.Map;
import java.util.Set;
public class Main {
    public static void main(String[] args) throws IOException{
        URL url = new URL("http://www.baidu.com");
        URLConnection conn = url.openConnection();
        Map headers = conn.getHeaderFields();
        Set<String> keys = headers.keySet();
        for( String key : keys ){
            String val = conn.getHeaderField(key);
            System.out.println(key+"    "+val);
        }
        System.out.println( conn.getLastModified() );
    }
}

以上代码运行输出结果为：

Accept-Ranges    bytes
null    HTTP/1.1 200 OK
Server    bfe/1.0.8.18
Etag    "588604c8-94d"
Cache-Control    private, no-cache, no-store, proxy-revalidate, no-transform
Connection    Keep-Alive
Set-Cookie    BDORZ=27315; max-age=86400; domain=.baidu.com; path=/
Pragma    no-cache
Last-Modified    Mon, 23 Jan 2017 13:27:36 GMT
Content-Length    2381
Date    Mon, 23 Sep 2019 05:36:41 GMT
Content-Type    text/html