1. 得到當前窗口句柄

2. 得到所有窗口句柄

3. 循環找到目標窗口

String currentWindow = driver.getWindowHandle();

Set<String> handles = driver.getWindowHandles();
Iterator<String> it = handles.iterator();
while (it.hasNext()) 
{
 String handle = it.next();
if (currentWindow.equals(handle))
　　continue; 
WebDriver window = driver.switchTo().window(handle);
}

Java Selenium - 處理頁面彈出窗