调用driver.close()后驱动的值被设置为

After calling driver.close() the value of driver is set to

FirefoxDriver: firefox on WINDOWS(4b4ffb1e-7c02-4d9c-b37b-310c771492ac)

但是如果你调用 driver.quit() 那么它会将 driver 的值设置为

But if you call driver.quit() then it sets the value of driver to

FirefoxDriver: firefox on WINDOWS (null)

因此，如果您在调用 driver.quit() 后检查浏览器窗口，那么您将能够通过以下实现知道.

So if you're checking the browser window after calling driver.quit() then you will be able to know by below implementation.

WebDriver driver = new FirefoxDriver();
driver.get("http://www.google.com");
driver.quit();              
if(driver.toString().contains("null"))
{

System.out.print("All Browser windows are closed ");
}
else
{
//open a new Browser
}