设置 java URLConnection 的用户代理
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Setting user agent of a java URLConnection
提问by DiglettPotato
I'm trying to parse a webpage using Java with URLConnection. I try to set up the user-agent like this:
我正在尝试使用带有 URLConnection 的 Java 解析网页。我尝试像这样设置用户代理：
java.net.URLConnection c = url.openConnection();
c.setRequestProperty("User-Agent", "Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.4; en-US; rv:1.9.2.2) Gecko/20100316 Firefox/3.6.2");
But the resulting user agent is the one I specify, with "Java/1.5.0_19" appended to the end. Is there a way to truly set the user agent without this addition?
但是生成的用户代理是我指定的，在末尾附加了“Java/1.5.0_19”。有没有办法在没有这个添加的情况下真正设置用户代理？
采纳答案by Tom Hawtin - tackline
Off hand, setting the http.agentsystem property to ""might do the trick (I don't have the code in front of me).
顺便说一句，将http.agent系统属性设置为""可能会起作用（我面前没有代码）。
You might get away with:
你可能会逃脱：
System.setProperty("http.agent", "");
but that might require a race between you and initialisation of the URL protocol handler, if it caches the value at startup (actually, I don't think it does).
但这可能需要在您和 URL 协议处理程序的初始化之间进行竞争，如果它在启动时缓存该值（实际上，我认为不会）。
The property can also be set through JNLP files (available to applets from 6u10) and on the command line:
该属性也可以通过 JNLP 文件（可用于 6u10 中的小程序）和在命令行上设置：
-Dhttp.agent=
Or for wrapper commands:
或者对于包装器命令：
-J-Dhttp.agent=
回答by juwens
Just for clarification: setRequestProperty("User-Agent", "Mozilla ...")now works just fine and doesn't append java/xxat the end! At least with Java 1.6.30 and newer.
只是为了澄清：setRequestProperty("User-Agent", "Mozilla ...")现在可以正常工作并且不会java/xx在最后追加！至少在 Java 1.6.30 和更新版本中。
I listened on my machine with netcat(a port listener):
我用 netcat（端口监听器）在我的机器上监听：
$ nc -l -p 8080
It simply listens on the port, so you see anything which gets requested, like raw http-headers.
它只是侦听端口，因此您可以看到请求的任何内容，例如原始 http 标头。
And got the following http-headers without setRequestProperty:
并在没有 setRequestProperty 的情况下获得以下 http 标头：
GET /foobar HTTP/1.1
User-Agent: Java/1.6.0_30
Host: localhost:8080
Accept: text/html, image/gif, image/jpeg, *; q=.2, */*; q=.2
Connection: keep-alive
And WITH setRequestProperty:
并使用 setRequestProperty：
GET /foobar HTTP/1.1
User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.4; en-US; rv:1.9.2.2) Gecko/20100316 Firefox/3.6.2
Host: localhost:8080
Accept: text/html, image/gif, image/jpeg, *; q=.2, */*; q=.2
Connection: keep-alive
As you can see the user agent was properly set.
如您所见，用户代理已正确设置。
Full example:
完整示例：
import java.io.IOException;
import java.net.URL;
import java.net.URLConnection;
public class TestUrlOpener {
public static void main(String[] args) throws IOException {
URL url = new URL("http://localhost:8080/foobar");
URLConnection hc = url.openConnection();
hc.setRequestProperty("User-Agent", "Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.4; en-US; rv:1.9.2.2) Gecko/20100316 Firefox/3.6.2");
System.out.println(hc.getContentType());
}
}
回答by Bachan Joseph
its work for me set the User-Agent in the addRequestProperty.
它对我的工作 在 addRequestProperty 中设置了 User-Agent。
URL url = new URL(<URL>);
HttpURLConnection httpConn = (HttpURLConnection) url.openConnection();
httpConn.addRequestProperty("User-Agent","Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:56.0) Gecko/20100101 Firefox/56.0");
回答by Sam Ginrich
HTTP Servers tend to reject old browsers and systems.
HTTP 服务器倾向于拒绝旧的浏览器和系统。
The page Tech Blog (wh): Most Common User Agentsreflects the user-agent property of your current browser in section "Your user agent is:", which can be applied to set the request property "User-Agent" of a java.net.URLConnectionor the system property "http.agent".
页面 技术博客 (wh): Most Common User Agents在“Your user agent is:”部分反映了您当前浏览器的 user-agent 属性，可用于设置 ajava.net.URLConnection或a 的请求属性“User-Agent”系统属性“http.agent”。
