Java HttpURLConnection getHeaderField() 方法

2025 年 3 月 22 日 | 阅读需 2 分钟

getHeaderField(int n) 是 HttpURLConnection 类的方法。此方法用于获取第 n 个头字段。当它是特殊的头字段（即第 0 个头字段）时，它返回 0。此方法还可以与 getHeaderFieldKey 方法一起使用，以获取消息的所有头信息。

语法

参数

n - 索引，其中 n >= 0。

返回值

它返回第 n 个头字段，否则返回 null。

示例 1

import java.io.IOException; 
import java.io.InputStream;
import java.net.HttpURLConnection; 
import java.net.URL; 
public class JavaHttpURLConnectiongetHeaderFieldExample1 {
    //Starting the main method...
    public static void main(String h[]) throws IOException 
	{ 
        //starting the try block
        try {
        String link_url ;
        link_url="https://tpointtech.cn";
        URL obj1 = new URL(link_url); //URL Connection Created...
        HttpURLConnection con1 = (HttpURLConnection) obj1.openConnection(); //Http URL Connection Created...
        con1.connect();
        System.out.println("Header field 0:" + con1.getHeaderField(0));
        System.out.println("Header field 1:" + con1.getHeaderField(1));
         HttpURLConnection.setFollowRedirects(true);
            System.out.println("getFollowRedirects : "+con1.getFollowRedirects());
        con1.setConnectTimeout(1000);
        con1.disconnect();
        System.out.println("connection disconnected");
        }
        catch (Exception e) {
            System.out.println( e);
        }
}
}

输出

Header field 0:HTTP/1.1 200 200
Header field 1:Thu, 29 Nov 2018 15:19:27 GMT
getFollowRedirects : true
connection disconnected

示例 2

import java.io.IOException; 
import java.io.InputStream;
import java.net.HttpURLConnection; 
import java.net.URL; 
public class JavaHttpURLConnectiongetHeaderFieldExample2 {
    //Starting the main method...
    public static void main(String h[]) throws IOException 
	{ 
        //starting the try block
        try {
        String link_url1, link_url2;
        link_url1="https://mysqlserver.cn";
        link_url2="https://www.oracle.com";
        URL obj1 = new URL(link_url1); //URL Connection Created...
        URL obj2 = new URL(link_url2);
        HttpURLConnection con1 = (HttpURLConnection) obj1.openConnection(); //Http URL Connection Created...
        HttpURLConnection con2 = (HttpURLConnection) obj2.openConnection();
        con1.connect();
        System.out.println("www.mysql.com");
        System.out.println("Header field 0:" + con1.getHeaderField(0));
        System.out.println("Header field 1:" + con1.getHeaderField(1));
        System.out.println("www.oracle.com");
        System.out.println("Header field 0:" + con2.getHeaderField(0));
        System.out.println("Header field 1:" + con2.getHeaderField(1));
         HttpURLConnection.setFollowRedirects(true);
            System.out.println("getFollowRedirects : "+con1.getFollowRedirects());
        con1.setConnectTimeout(1000);
        con1.disconnect();
        System.out.println("connection disconnected");
        }
        catch (Exception e) {
            System.out.println( e);
        }
}
}

输出

www.mysql.com
Header field 0:HTTP/1.1 200 OK
Header field 1:Thu, 29 Nov 2018 15:25:37 GMT
www.oracle.com
Header field 0:HTTP/1.1 200 OK
Header field 1:Oracle-HTTP-Server
getFollowRedirects : true
connection disconnected

下一个主题Java HttpURLConnection 类

Java HttpURLConnection getHeaderField() 方法

语法

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示例 1

示例 2

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Java HttpURLConnection getHeaderField() 方法

语法

参数

返回值

示例 1

示例 2

相关帖子

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Java HttpURLConnection

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