我不明白为什么 Java 的 HttpURLConnection
不遵循从 HTTP 到 HTTPS URL 的 HTTP 重定向。我使用以下代码获取位于 https://httpstat.us/ 的页面:
import java.net.URL;
import java.net.HttpURLConnection;
import java.io.InputStream;
public class Tester {
public static void main(String argv[]) throws Exception{
InputStream is = null;
try {
String httpUrl = "http://httpstat.us/301";
URL resourceUrl = new URL(httpUrl);
HttpURLConnection conn = (HttpURLConnection)resourceUrl.openConnection();
conn.setConnectTimeout(15000);
conn.setReadTimeout(15000);
conn.connect();
is = conn.getInputStream();
System.out.println("Original URL: "+httpUrl);
System.out.println("Connected to: "+conn.getURL());
System.out.println("HTTP response code received: "+conn.getResponseCode());
System.out.println("HTTP response message received: "+conn.getResponseMessage());
} finally {
if (is != null) is.close();
}
}
}
这个程序的输出是:
Original URL: http://httpstat.us/301 Connected to: http://httpstat.us/301 HTTP response code received: 301 HTTP response message received: Moved Permanently
A request to http://httpstat.us/301 returns the following (shortened) response (which seems absolutely right!):
HTTP/1.1 301 Moved Permanently
Cache-Control: private
Content-Length: 21
Content-Type: text/plain; charset=utf-8
Location: https://httpstat.us
很遗憾,Java 的 HttpURLConnection
不遵循重定向!
请注意,如果您将原始 URL 更改为 HTTPS (https://httpstat.us/301),Java 将按预期遵循重定向!?
最佳答案
仅当它们使用相同的协议(protocol)时才会遵循重定向。 (参见源代码中的 the followRedirect()
method。)无法禁用此检查。
尽管我们知道它反射(reflect)了 HTTP,但从 HTTP 协议(protocol)的角度来看,HTTPS 只是另一种完全不同的未知协议(protocol)。未经用户批准就跟随重定向是不安全的。
例如,假设应用程序设置为自动执行客户端身份验证。用户希望匿名上网,因为他使用的是 HTTP。但是,如果他的客户端在不询问的情况下使用 HTTPS,他的身份就会暴露给服务器。
关于java - HTTPURLConnection 不遵循从 HTTP 到 HTTPS 的重定向,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/1884230/