java - Selenium:http://localhost:4444/wd/hub 返回 NullPointerException，我做错了什么

Question

给定:尝试在 C# 中使用此代码使用 RemoteWebDriver。

var url = new Uri("http://localhost:4444/wd/hub");
var wd = new RemoteWebDriver(url, DesiredCapabilities.Chrome());

上面的新 RemoteWebDriver 代码在超时之前不会响应...

更多详情

我已经使用这些参数启动了我的集线器到 Selenium 服务器:

-jar "C:\SomeFolder\selenium-server-standalone-3.0.1.jar" -port 4444 -role hub

并使用这些参数注册了一个节点..

-jar "C:\SomeFolder\selenium-server-standalone-3.0.1.jar" -role node -hub http://localhost:4444/grid/register -port 9662 

调试

如果我在启动 Hub 后输入这个 URL，它显示有一个已注册的节点:

http://location:4444/grid/console

但是在启动 Hub 后输入这个 url 时

http://localhost:4444/wd/hub

浏览器显示指向 ExternalSessionKey.java 的 java (json) 堆栈跟踪

{"status":13,"value":{"class":"java.lang.NullPointerException","stackTrace":[{"fileName":"ExternalSessionKey.java","className":"org.openqa.grid.internal.ExternalSessionKey","methodName":"fromWebDriverRequest","lineNumber":77},{"fileName":"WebDriverRequest.java","className":"org.openqa.grid.web.servlet.handler.WebDriverRequest","methodName":"extractSession","lineNumber":62},{"fileName":"RequestHandler.java","className":"org.openqa.grid.web.servlet.handler.RequestHandler","methodName":"getSession","lineNumber":231},{"fileName":"RequestHandler.java","className":"org.openqa.grid.web.servlet.handler.RequestHandler","methodName":"process","lineNumber":118},{"fileName":"DriverServlet.java","className":"org.openqa.grid.web.servlet.DriverServlet","methodName":"process","lineNumber":83},{"fileName":"DriverServlet.java","className":"org.openqa.grid.web.servlet.DriverServlet","methodName":"doGet","lineNumber":61},{"fileName":"HttpServlet.java","className":"javax.servlet.http.HttpServlet","methodName":"service","lineNumber":687},{"fileName":"HttpServlet.java","className":"javax.servlet.http.HttpServlet","methodName":"service","lineNumber":790},{"fileName":"ServletHolder.java","className":"org.seleniumhq.jetty9.servlet.ServletHolder","methodName":"handle","lineNumber":808},{"fileName":"ServletHandler.java","className":"org.seleniumhq.jetty9.servlet.ServletHandler","methodName":"doHandle","lineNumber":587},{"fileName":"SessionHandler.java","className":"org.seleniumhq.jetty9.server.session.SessionHandler","methodName":"doHandle","lineNumber":221},{"fileName":"ContextHandler.java","className":"org.seleniumhq.jetty9.server.handler.ContextHandler","methodName":"doHandle","lineNumber":1127},{"fileName":"ServletHandler.java","className":"org.seleniumhq.jetty9.servlet.ServletHandler","methodName":"doScope","lineNumber":515},{"fileName":"SessionHandler.java","className":"org.seleniumhq.jetty9.server.session.SessionHandler","methodName":"doScope","lineNumber":185},{"fileName":"ContextHandler.java","className":"org.seleniumhq.jetty9.server.handler.ContextHandler","methodName":"doScope","lineNumber":1061},{"fileName":"ScopedHandler.java","className":"org.seleniumhq.jetty9.server.handler.ScopedHandler","methodName":"handle","lineNumber":141},{"fileName":"HandlerWrapper.java","className":"org.seleniumhq.jetty9.server.handler.HandlerWrapper","methodName":"handle","lineNumber":97},{"fileName":"Server.java","className":"org.seleniumhq.jetty9.server.Server","methodName":"handle","lineNumber":499},{"fileName":"HttpChannel.java","className":"org.seleniumhq.jetty9.server.HttpChannel","methodName":"handle","lineNumber":310},{"fileName":"HttpConnection.java","className":"org.seleniumhq.jetty9.server.HttpConnection","methodName":"onFillable","lineNumber":257},{"fileName":"AbstractConnection.java","className":"org.seleniumhq.jetty9.io.AbstractConnection$2","methodName":"run","lineNumber":540},{"fileName":"QueuedThreadPool.java","className":"org.seleniumhq.jetty9.util.thread.QueuedThreadPool","methodName":"runJob","lineNumber":635},{"fileName":"QueuedThreadPool.java","className":"org.seleniumhq.jetty9.util.thread.QueuedThreadPool$3","methodName":"run","lineNumber":555},{"className":"java.lang.Thread","methodName":"run","lineNumber":-1}]}}

任何人都可以为我解释 Stack Trace，以及如何使它正常工作？

谢谢!

Answer 1

你这边没有问题。

URL http://localhost:4444/wd/hub 被设计成它期望你的操作有一个 PAYLOAD。由于您没有提供所需的负载，您会看到 NullPointerException。

此 URL 不应在浏览器中打开。它意味着通过 Http 操作使用符合 Selenium w3c spec 的适当有效载荷。