Selenium WebDriver 如何解决过时的元素引用异常? [英] Selenium WebDriver How to Resolve Stale Element Reference Exception?
问题描述
我在 Selenium 2 Web Driver 测试中有以下代码，它在我调试时工作，但在构建中运行时大部分时间都失败.我知道这一定与页面未被刷新的方式有关，但不知道如何解决它，因此对我做错了什么的任何指示表示赞赏.我使用 JSF primefaces 作为我的 Web 应用程序框架.当我单击添加新链接时，会出现一个带有输入框的弹出对话框，我可以在其中输入日期，然后单击保存.正是在让 input 元素输入文本时，我得到了一个陈旧的元素引用异常.
I have the following code in a Selenium 2 Web Driver test which works when I am debugging but most of the time fails when I run it in the build. I know it must be something to do with the way the page is not being refreshed but do not know how to resolve it so any pointers as to what I have done wrong are appreciated. I am using JSF primefaces as my web application framework. When I click on the add new link a popup dialog box appears with a input box that I can enter a date into then click save. It is on getting the input element to enter text into that I get a stale element ref exception.
提前致谢
import static org.junit.Assert.assertEquals;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.junit.Test;
import org.openqa.selenium.By;
import org.openqa.selenium.StaleElementReferenceException;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.chrome.ChromeDriver;
import org.openqa.selenium.support.ui.ExpectedCondition;
import org.openqa.selenium.support.ui.WebDriverWait;
public class EnterActiveSubmissionIntegrationTest {
Map<String, Map<String, String>> tableData = new HashMap<String, Map<String, String>>();
@Test
public void testEnterActiveSubmission() throws Exception {
// Create a new instance of the Firefox driver
// Notice that the remainder of the code relies on the interface,
// not the implementation.
System.setProperty("webdriver.chrome.driver", "C:/apps/chromedriver.exe");
WebDriver driver = new ChromeDriver();
// And now use this to visit Google
driver.get("http://localhost:8080/strfingerprinting");
// Alternatively the same thing can be done like this
// driver.navigate().to("http://www.google.com");
// Find the text input element by its name
WebElement element = driver.findElement(By.linkText("Manage Submissions"));
element.click();
parseTableData(driver, "form:submissionDataTable_data", 1);
assertEquals(tableData.get("form:submissionDataTable_data").get("12"), "Archived");
WebElement newElement = driver.findElement(By.linkText("Add new"));
newElement.click();
WebDriverWait wait = new WebDriverWait(driver,10);
wait.until(new ExpectedCondition<Boolean>() {
public Boolean apply(WebDriver driver) {
WebElement button = driver.findElement(By
.name("createForm:dateInput_input"));
if (button.isDisplayed())
return true;
else
return false;
}
});
WebElement textElement = driver.findElement(By.name("createForm:dateInput_input"));
textElement.sendKeys("24/04/2013");
WebElement saveElement = driver.findElement(By.name("createForm:saveButton"));
saveElement.click();
driver.navigate().refresh();
parseTableData(driver, "form:submissionDataTable_data", 2);
//Close the browser
driver.quit();
}
private void parseTableData(WebDriver driver, String id, int expectedRows) {
// Check the title of the page or expected element on page
WebElement subTableElement = driver.findElement(By.id(id));
List<WebElement> tr_collection=subTableElement.findElements(By.xpath("id('"+ id + "')/tr"));
assertEquals("incorrect number of rows returned", expectedRows, tr_collection.size());
int row_num,col_num;
row_num=1;
if(tableData.get(id) == null) {
tableData.put(id, new HashMap<String, String>());
}
Map<String, String> subTable = tableData.get(id);
for(WebElement trElement : tr_collection)
{
List<WebElement> td_collection=trElement.findElements(By.xpath("td"));
col_num=1;
for(WebElement tdElement : td_collection)
{
subTable.put(row_num + "" + col_num, tdElement.getText());
col_num++;
}
row_num++;
}
}
}
当我运行它时，我得到以下异常，但它可能发生在
When I run this I get the following exception but it can occur on
WebElement textElement = driver.findElement(By.name("createForm:dateInput_input"));
或
if (button.isDisplayed())
异常跟踪
org.openqa.selenium.StaleElementReferenceException: stale element reference: element is not attached to the page document
(Session info: chrome=26.0.1410.64)
(Driver info: chromedriver=0.8,platform=Windows NT 6.0 SP2 x86) (WARNING: The server did not provide any stacktrace information)
Command duration or timeout: 56 milliseconds
For documentation on this error, please visit: http://seleniumhq.org/exceptions/stale_element_reference.html
Build info: version: '2.32.0', revision: '6c40c187d01409a5dc3b7f8251859150c8af0bcb', time: '2013-04-09 10:39:28'
System info: os.name: 'Windows Vista', os.arch: 'x86', os.version: '6.0', java.version: '1.6.0_10'
Session ID: 784c53b99ad83c44d089fd04e9a42904
Driver info: org.openqa.selenium.chrome.ChromeDriver
Capabilities [{platform=XP, acceptSslCerts=true, javascriptEnabled=true, browserName=chrome, rotatable=false, driverVersion=0.8, locationContextEnabled=true, version=26.0.1410.64, cssSelectorsEnabled=true, databaseEnabled=true, handlesAlerts=true, browserConnectionEnabled=false, nativeEvents=true, webStorageEnabled=true, applicationCacheEnabled=false, takesScreenshot=true}]
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
at org.openqa.selenium.remote.ErrorHandler.createThrowable(ErrorHandler.java:187)
at org.openqa.selenium.remote.ErrorHandler.throwIfResponseFailed(ErrorHandler.java:145)
at org.openqa.selenium.remote.RemoteWebDriver.execute(RemoteWebDriver.java:554)
at org.openqa.selenium.remote.RemoteWebElement.execute(RemoteWebElement.java:268)
at org.openqa.selenium.remote.RemoteWebElement.isDisplayed(RemoteWebElement.java:320)
at com.integration.web.EnterActiveSubmissionIntegrationTest$1.apply(EnterActiveSubmissionIntegrationTest.java:58)
at com.integration.web.EnterActiveSubmissionIntegrationTest$1.apply(EnterActiveSubmissionIntegrationTest.java:1)
at org.openqa.selenium.support.ui.FluentWait.until(FluentWait.java:208)
at com.integration.web.EnterActiveSubmissionIntegrationTest.testEnterActiveSubmission(EnterActiveSubmissionIntegrationTest.java:53)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
推荐答案
首先让我们清楚什么是 WebElement.
First of all lets be clear about what a WebElement is.
WebElement 是对 DOM 中元素的引用.
A WebElement is a reference to an element in the DOM.
当您正在交互的元素被销毁然后重新创建时，会抛出 StaleElementException.如今，大多数复杂的网页都会在用户与其交互时动态移动内容，这需要销毁和重新创建 DOM 中的元素.
A StaleElementException is thrown when the element you were interacting is destroyed and then recreated. Most complex web pages these days will move things about on the fly as the user interacts with it and this requires elements in the DOM to be destroyed and recreated.
当发生这种情况时，您之前拥有的 DOM 中元素的引用将变得陈旧，您将无法再使用此引用与 DOM 中的元素进行交互.发生这种情况时，您将需要刷新您的参考，或者在现实世界中再次找到该元素.
When this happens the reference to the element in the DOM that you previously had becomes stale and you are no longer able to use this reference to interact with the element in the DOM. When this happens you will need to refresh your reference, or in real world terms find the element again.
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