getWindowHandles()可以正常工作，但是在调用之前，getWindowHandles()您必须按照以下步骤诱使webdriverwait ：
System.setProperty("webdriver.gecko.driver", "C:\\Utility\\BrowserDrivers\\geckodriver.exe");
WebDriver driver= new FirefoxDriver();
driver.get("https://www.facebook.com/");
String parent= driver.getWindowHandle();
System.out.println("Parent Window is"+parent);
driver.findElement(By.linkText("Data Policy")).click();
webdriverwait wait = new webdriverwait(driver,5);
wait.until(ExpectedConditions.numberOfWindowsToBe(2));
Set<String> s1= driver.getWindowHandles();
for(String s2:s1)
{
if(!parent.equalsIgnoreCase(s2))
{
driver.switchTo().window(s2);
Thread.sleep(5000);
System.out.println(driver.getWindowHandle());
System.out.println("get title of window"+driver.getTitle());
}
}
控制台输出：
Parent Window is4294967297
4294967303
get title of windowData Policy
602392714
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