org.openqa.selenium.json.JsonException：预期读取 START_MAP，但结果却是：END。通过 Node 执行测试时读取的最后 0 个字符

Question

我是 Selenium 的新手并开始学习它。但 Selenium Grid 不适合我。使用的服务器版本是selenium-server-standalone-3.14.0.jar。使用命令，集线器和节点正在运行。将节点添加到 hub 的代码是使用 Eclipse 中的 TestNG 编写的。代码如下：

ChromeOptions options = new ChromeOptions();
options.setCapability(CapabilityType.PLATFORM_NAME, Platform.WIN10);             
options.setCapability(CapabilityType.BROWSER_NAME, "chrome");
driver = new RemoteWebDriver(new URL("http://192.xxx.x.xx:48807/wd/hub"), options);             driver.get("https://www.amazon.in/");

运行测试时，出现以下错误并且未创建会话：

org.openqa.selenium.WebDriverException: Unable to parse remote response: 
    at org.openqa.selenium.remote.ProtocolHandshake.createSession(ProtocolHandshake.java:111)
    at org.openqa.selenium.remote.ProtocolHandshake.createSession(ProtocolHandshake.java:73)
    at org.openqa.selenium.remote.HttpCommandExecutor.execute(HttpCommandExecutor.java:136)
    at org.openqa.selenium.remote.RemoteWebDriver.execute(RemoteWebDriver.java:548)
    at org.openqa.selenium.remote.RemoteWebDriver.startSession(RemoteWebDriver.java:212)
    at org.openqa.selenium.remote.RemoteWebDriver.<init>(RemoteWebDriver.java:130)
    at org.openqa.selenium.remote.RemoteWebDriver.<init>(RemoteWebDriver.java:143)
    at grid.Node2.f(Node2.java:44)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:124)
    at org.testng.internal.Invoker.invokeMethod(Invoker.java:580)
    at org.testng.internal.Invoker.invokeTestMethod(Invoker.java:716)
    at org.testng.internal.Invoker.invokeTestMethods(Invoker.java:988)
    at org.testng.internal.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:125)
    at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:109)
    at org.testng.TestRunner.privateRun(TestRunner.java:648)
    at org.testng.TestRunner.run(TestRunner.java:505)
    at org.testng.SuiteRunner.runTest(SuiteRunner.java:455)
    at org.testng.SuiteRunner.access$000(SuiteRunner.java:40)
    at org.testng.SuiteRunner$SuiteWorker.run(SuiteRunner.java:489)
    at org.testng.internal.thread.ThreadUtil$1.call(ThreadUtil.java:52)
    at java.util.concurrent.FutureTask.run(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
Caused by: org.openqa.selenium.json.JsonException: Expected to read a START_MAP but instead have: END. Last 0 characters read: 
Build info: version: '3.14.0', revision: 'aacccce0', time: '2018-08-

集线器命令：

java -jar selenium-server-standalone-3.14.0.jar -role hub

节点命令：java -DWebdriver.chrome.driver=C:\SWs\chromedriver_win32\chromedriver.exe -jar selenium-server-standalone-3.14.0.jar -role node -hub http://xxx.xxx.xx:4444 /网格/注册/

浏览器详细信息：Chrome 69
ChromeDriver 2.42.591088

任何人都请帮忙解决这个问题，提前致谢

Answer 1

对这个错误有点惊讶：

org.openqa.selenium.json.JsonException: Expected to read a START_MAP but instead have: END. Last 0 characters read

根据Selenium 3.12.0 Windows org.openqa.selenium.json.JsonException: Cannot coerce something that is not a number to a number: STRING修复应该在Selenium v​​3.14.0中可用，关于提交允许数字强制隐式将字符串强制转换为数字。错误应该是：

Cannot coerce something that is not a number to a number: " + type

当您使用Selenium v​​3.14.0二进制文件时，您似乎正在使用已弃用的函数。

根据文档CapabilityType不是PLATFORM_NAME有效的配置，您需要将其更改为PLATFORM。

在我的带有Selenium v​​3.14.0二进制文件的Windows 8系统上，这里是执行完美的解决方案：

• 代码块：

  import java.net.MalformedURLException;
  import java.net.URL;
  
  import org.openqa.selenium.Platform;
  import org.openqa.selenium.WebDriver;
  import org.openqa.selenium.chrome.ChromeOptions;
  import org.openqa.selenium.remote.CapabilityType;
  import org.openqa.selenium.remote.RemoteWebDriver;
  import org.testng.annotations.Test;
  
  public class testChromeOnGrid_test 
  {
  
      @Test
      public void test1() throws MalformedURLException
      {
          System.setProperty("webdriver.chrome.driver", "C:\\Utility\\BrowserDrivers\\chromedriver.exe");
          ChromeOptions options = new ChromeOptions();
          options.setCapability(CapabilityType.PLATFORM, Platform.WIN8);           
          options.setCapability(CapabilityType.BROWSER_NAME, "chrome");
          WebDriver driver = new RemoteWebDriver(new URL("http://localhost:4444/wd/hub"), options);
          driver.get("http://google.com/");
          System.out.println("Title is : "+driver.getTitle());
          driver.quit();
      }
  }
  

• 控制台输出：

  [RemoteTestNG] detected TestNG version 6.14.2
  Oct 16, 2018 3:00:57 PM org.openqa.selenium.remote.ProtocolHandshake createSession
  INFO: Detected dialect: OSS
  Title is : Google
  PASSED: test1
  
  ===============================================
      Default test
      Tests run: 1, Failures: 0, Skips: 0
  ===============================================
  
  
  ===============================================
  Default suite
  Total tests run: 1, Failures: 0, Skips: 0
  ===============================================
  

更新

根据您的问题更新，您使用的Selenium 网格节点启动命令存在问题。使用命令如下：

• 要为ChromeDriver和Chrome注册Selenium 网格节点，您需要传递ChromeDriver的绝对路径 ，如下所示：

  >java -DWebdriver.chrome.driver=C:\\path\\to\\chromedriver.exe -jar selenium-server-standalone-3.14.0.jar -role node -hub http://<IP_GRID_HUB>:4444/grid/register/