java - Selenium CSS 选择器

Question

我是 Selenium 的新手。我正在尝试使用以下代码在 Stack Overflow 网站上运行一个套件。该代码生成 NoSuchElement 异常。我正在使用 selenium java 客户端和服务器(3.7.1)以及 Chrome 驱动程序(2.33)。使用 Java 9。在 Windows 10 上。

我已使用 Chrome 开发者工具上的查找功能验证了 css 选择器。

可能是什么问题？

public class Suite {

    private static final String home = "https://stackoverflow.com";
    private  WebDriver driver = null;

    public static void main(String[] args) {

        Suite suite = new Suite(true);

            suite.login()
                .clickByCSSSelector("a.my-profile");

    }
    public Suite(boolean isHeadLess) {

        ChromeOptions option = new ChromeOptions();
        if (isHeadLess) option.addArguments("--headless");
        System.setProperty("webdriver.chrome.driver", "D:\\work\\webscraping\\chromedriver\\chromedriver.exe");

        driver = new ChromeDriver(option);
    }
    public Suite login() {

        this.navigate(home)
            .setValue("email", "xxxx@gmail.com")
            .setValue("password", "xxxxxx")
            .click("submit-button");
        return this;

    }
    public Suite navigate(String target) {
        driver.navigate().to(target);
        return this;
    }
    public Suite setValue(String elementId, String value) {
        driver.findElement(By.id(elementId)).sendKeys(value);
        return this;
    }
    public Suite clickByXpath(String xpath) {
        this.findByXpath(xpath).click();
        return this;
    }
    public Suite clickByCSSSelector(String selector) {
        this.findByCSSSelector(selector).click();
        return this;
    }   
    private WebElement findByCSSSelector(String selector) {
        return driver.findElement(By.cssSelector(selector));

    }
    public WebElement findByXpath(String xpath) {
        return this.find(By.xpath(xpath));
    }

    public WebElement find(By element) {
        return driver.findElement(element);
    }
    public Suite click(String elementId) {
        this.find(elementId).click();
        return this;
    }
    public WebElement find(String elementId) {
        return this.find(By.id(elementId));
    }

}

异常(exception):

Exception in thread "main" org.openqa.selenium.NoSuchElementException: no such element: Unable to locate element: {"method":"css selector","selector":"a.my-profile"}
  (Session info: headless chrome=62.0.3202.94)
  (Driver info: chromedriver=2.33.506120 (e3e53437346286c0bc2d2dc9aa4915ba81d9023f),platform=Windows NT 10.0.14393 x86_64) (WARNING: The server did not provide any stacktrace information)
Command duration or timeout: 0 milliseconds
For documentation on this error, please visit: http://seleniumhq.org/exceptions/no_such_element.html
Build info: version: '3.7.1', revision: '8a0099a', time: '2017-11-06T21:01:39.354Z'
System info: host: 'HMECL000593', ip: '10.0.75.1', os.name: 'Windows 10', os.arch: 'amd64', os.version: '10.0', java.version: '9'
Driver info: org.openqa.selenium.chrome.ChromeDriver
Capabilities {acceptSslCerts: true, applicationCacheEnabled: false, browserConnectionEnabled: false, browserName: chrome, chrome: {chromedriverVersion: 2.33.506120 (e3e53437346286..., userDataDir: C:\Users\TOMS~1.VAR\AppData...}, cssSelectorsEnabled: true, databaseEnabled: false, handlesAlerts: true, hasTouchScreen: false, javascriptEnabled: true, locationContextEnabled: true, mobileEmulationEnabled: false, nativeEvents: true, networkConnectionEnabled: false, pageLoadStrategy: normal, platform: XP, platformName: XP, rotatable: false, setWindowRect: true, takesHeapSnapshot: true, takesScreenshot: true, unexpectedAlertBehaviour: , unhandledPromptBehavior: , version: 62.0.3202.94, webStorageEnabled: true}
Session ID: fa8665d6bf99e34431e27b91ec3a1458
*** Element info: {Using=css selector, value=a.my-profile}
    at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:488)
    at org.openqa.selenium.remote.ErrorHandler.createThrowable(ErrorHandler.java:214)
    at org.openqa.selenium.remote.ErrorHandler.throwIfResponseFailed(ErrorHandler.java:166)
    at org.openqa.selenium.remote.http.JsonHttpResponseCodec.reconstructValue(JsonHttpResponseCodec.java:40)
    at org.openqa.selenium.remote.http.AbstractHttpResponseCodec.decode(AbstractHttpResponseCodec.java:80)
    at org.openqa.selenium.remote.http.AbstractHttpResponseCodec.decode(AbstractHttpResponseCodec.java:44)
    at org.openqa.selenium.remote.HttpCommandExecutor.execute(HttpCommandExecutor.java:164)
    at org.openqa.selenium.remote.service.DriverCommandExecutor.execute(DriverCommandExecutor.java:83)
    at org.openqa.selenium.remote.RemoteWebDriver.execute(RemoteWebDriver.java:600)
    at org.openqa.selenium.remote.RemoteWebDriver.findElement(RemoteWebDriver.java:370)
    at org.openqa.selenium.remote.RemoteWebDriver.findElementByCssSelector(RemoteWebDriver.java:464)
    at org.openqa.selenium.By$ByCssSelector.findElement(By.java:430)
    at org.openqa.selenium.remote.RemoteWebDriver.findElement(RemoteWebDriver.java:362)
    at com.tv.webscraping.selenium.SeleniumClient.findByCSSSelector(SeleniumClient.java:81)
    at com.tv.webscraping.selenium.SeleniumClient.clickByCSSSelector(SeleniumClient.java:76)
    at com.tv.webscraping.selenium.Suite.main(Suite.java:19)

Chrome 开发者工具:

Answer 1

您可能还需要在点击之前等待

WebDriverWait wait = new WebDriverWait(webDriver, timeoutInSeconds);

wait.until(ExpectedConditions.visibilityOfElementLocated(By.id<locator>));

在此处查看有关等待的更多信息:WebDriver - wait for element using Java

如果这不起作用，请尝试以下 xpath，并结合上面的等待 .clickByXpath("//a[contains(@class, 'my-profile')]");

下面有更多信息来解释 xpath:

• 多个匹配://div[@class='class' and contains(text(), 'text')]
• 部分匹配://span[contains(class, 'class')]
• starts-with: //input[starts-with(@name,'input')这些在处理动态元素时更有益并且更稳健。

在此处查看有关 xpath 的更多信息:https://sqa.stackexchange.com/questions/10342/how-to-find-element-using-contains-in-xpath

请注意:我仅建议当元素是动态的或没有唯一 ID 时使用 xpath

此外，您可以使用类名而不是 xpath，我在 C# 中执行此操作的示例是 driver.FindElement(By.ClassName("my-profile js-gps-track");

如果上述所有方法都不起作用，您可能需要使用如下操作:

Actions actions = new Actions(driver);
actions.moveToElement(driver.findElement(By.id(id)));
actions.click();
actions.build().perform();