找不到我可以从 Chrome 浏览器的检查窗口中看到的带有 Selenium 的 WebElements

Question

编辑：它适用于 chrome 驱动程序，但不适用于 HtmlUnitDriver，为什么？

我正在尝试使用 classname = "cat-pick_i" 获取 WebElements

我可以在 Chrome 的检查窗口中看到这些元素，如下所示

我的代码如下，

WebDriver driver = new HtmlUnitDriver(true);

    driver.get("https://amzscout.net/sales-estimator");
    System.out.println("Title : "+driver.getTitle());

    WebElement pickList = driver.findElement(By.className("cat-pick_list"));
    System.out.println(pickList.toString());

    List<WebElement> elements = pickList.findElements(By.className("cat-pick_i"));
    System.out.println("num of categories : "+elements.size());

    for (int i = 0; i <elements.size() ; i++) {
        WebElement element = elements.get(i).findElement(By.className("cat-pick_name-in"));
        System.out.println(element.getText());
    }

而我的代码输出如下，

Title : Amazon Products Sales History Estimator, Rank Calculator | AMZScout
<div class="cat-pick_list" />
num of categories : 0

Process finished with exit code 0

我的问题是为什么我不能得到那些 WebElements，我怎么能得到它们。

编辑：还有来自 HtmlUnitDriver 的警告可能会有所帮助

    Oct 29, 2018 6:22:29 PM com.gargoylesoftware.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://amzscout.net/css/common.css' [1:4132] Error in expression. (Invalid token " ". Was expecting one of: <NUMBER>, "inherit", <IDENT>, <STRING>, <HASH>, <EMS>, <EXS>, <LENGTH_PX>, <LENGTH_CM>, <LENGTH_MM>, <LENGTH_IN>, <LENGTH_PT>, <LENGTH_PC>, <ANGLE_DEG>, <ANGLE_RAD>, <ANGLE_GRAD>, <TIME_MS>, <TIME_S>, <FREQ_HZ>, <FREQ_KHZ>, <RESOLUTION_DPI>, <RESOLUTION_DPCM>, <PERCENTAGE>, <DIMENSION>, <UNICODE_RANGE>, <URI>, <FUNCTION>, "progid:".)
Oct 29, 2018 6:22:29 PM com.gargoylesoftware.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://amzscout.net/css/common.css' [1:4162] Error in expression. (Invalid token " ". Was expecting one of: <NUMBER>, "inherit", <IDENT>, <STRING>, <HASH>, <EMS>, <EXS>, <LENGTH_PX>, <LENGTH_CM>, <LENGTH_MM>, <LENGTH_IN>, <LENGTH_PT>, <LENGTH_PC>, <ANGLE_DEG>, <ANGLE_RAD>, <ANGLE_GRAD>, <TIME_MS>, <TIME_S>, <FREQ_HZ>, <FREQ_KHZ>, <RESOLUTION_DPI>, <RESOLUTION_DPCM>, <PERCENTAGE>, <DIMENSION>, <UNICODE_RANGE>, <URI>, <FUNCTION>, "progid:".)
Oct 29, 2018 6:22:29 PM com.gargoylesoftware.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://amzscout.net/css/common.css' [1:7255] Error in expression. (Invalid token " ". Was expecting one of: <NUMBER>, "inherit", <IDENT>, <STRING>, <HASH>, <EMS>, <EXS>, <LENGTH_PX>, <LENGTH_CM>, <LENGTH_MM>, <LENGTH_IN>, <LENGTH_PT>, <LENGTH_PC>, <ANGLE_DEG>, <ANGLE_RAD>, <ANGLE_GRAD>, <TIME_MS>, <TIME_S>, <FREQ_HZ>, <FREQ_KHZ>, <RESOLUTION_DPI>, <RESOLUTION_DPCM>, <PERCENTAGE>, <DIMENSION>, <UNICODE_RANGE>, <URI>, <FUNCTION>, "progid:".)
Oct 29, 2018 6:22:29 PM com.gargoylesoftware.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://amzscout.net/css/common.css' [1:7276] Error in expression. (Invalid token " ". Was expecting one of: <NUMBER>, "inherit", <IDENT>, <STRING>, <HASH>, <EMS>, <EXS>, <LENGTH_PX>, <LENGTH_CM>, <LENGTH_MM>, <LENGTH_IN>, <LENGTH_PT>, <LENGTH_PC>, <ANGLE_DEG>, <ANGLE_RAD>, <ANGLE_GRAD>, <TIME_MS>, <TIME_S>, <FREQ_HZ>, <FREQ_KHZ>, <RESOLUTION_DPI>, <RESOLUTION_DPCM>, <PERCENTAGE>, <DIMENSION>, <UNICODE_RANGE>, <URI>, <FUNCTION>, "progid:".)
Oct 29, 2018 6:22:29 PM com.gargoylesoftware.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://amzscout.net/css/common.css' [1:11589] Error in expression. (Invalid token " ". Was expecting one of: <NUMBER>, "inherit", <IDENT>, <STRING>, <HASH>, <EMS>, <EXS>, <LENGTH_PX>, <LENGTH_CM>, <LENGTH_MM>, <LENGTH_IN>, <LENGTH_PT>, <LENGTH_PC>, <ANGLE_DEG>, <ANGLE_RAD>, <ANGLE_GRAD>, <TIME_MS>, <TIME_S>, <FREQ_HZ>, <FREQ_KHZ>, <RESOLUTION_DPI>, <RESOLUTION_DPCM>, <PERCENTAGE>, <DIMENSION>, <UNICODE_RANGE>, <URI>, <FUNCTION>, "progid:".)
Oct 29, 2018 6:22:29 PM com.gargoylesoftware.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://amzscout.net/css/common.css' [1:11609] Error in expression. (Invalid token " ". Was expecting one of: <NUMBER>, "inherit", <IDENT>, <STRING>, <HASH>, <EMS>, <EXS>, <LENGTH_PX>, <LENGTH_CM>, <LENGTH_MM>, <LENGTH_IN>, <LENGTH_PT>, <LENGTH_PC>, <ANGLE_DEG>, <ANGLE_RAD>, <ANGLE_GRAD>, <TIME_MS>, <TIME_S>, <FREQ_HZ>, <FREQ_KHZ>, <RESOLUTION_DPI>, <RESOLUTION_DPCM>, <PERCENTAGE>, <DIMENSION>, <UNICODE_RANGE>, <URI>, <FUNCTION>, "progid:".)
Oct 29, 2018 6:22:29 PM com.gargoylesoftware.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://amzscout.net/css/common.css' [1:11723] Error in expression. (Invalid token " ". Was expecting one of: <NUMBER>, "inherit", <IDENT>, <STRING>, <HASH>, <EMS>, <EXS>, <LENGTH_PX>, <LENGTH_CM>, <LENGTH_MM>, <LENGTH_IN>, <LENGTH_PT>, <LENGTH_PC>, <ANGLE_DEG>, <ANGLE_RAD>, <ANGLE_GRAD>, <TIME_MS>, <TIME_S>, <FREQ_HZ>, <FREQ_KHZ>, <RESOLUTION_DPI>, <RESOLUTION_DPCM>, <PERCENTAGE>, <DIMENSION>, <UNICODE_RANGE>, <URI>, <FUNCTION>, "progid:".)
Oct 29, 2018 6:22:29 PM com.gargoylesoftware.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://amzscout.net/css/common.css' [1:11744] Error in expression. (Invalid token " ". Was expecting one of: <NUMBER>, "inherit", <IDENT>, <STRING>, <HASH>, <EMS>, <EXS>, <LENGTH_PX>, <LENGTH_CM>, <LENGTH_MM>, <LENGTH_IN>, <LENGTH_PT>, <LENGTH_PC>, <ANGLE_DEG>, <ANGLE_RAD>, <ANGLE_GRAD>, <TIME_MS>, <TIME_S>, <FREQ_HZ>, <FREQ_KHZ>, <RESOLUTION_DPI>, <RESOLUTION_DPCM>, <PERCENTAGE>, <DIMENSION>, <UNICODE_RANGE>, <URI>, <FUNCTION>, "progid:".)
Oct 29, 2018 6:22:29 PM com.gargoylesoftware.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://amzscout.net/css/common.css' [1:12259] Error in expression. (Invalid token " ". Was expecting one of: <NUMBER>, "inherit", <IDENT>, <STRING>, <HASH>, <EMS>, <EXS>, <LENGTH_PX>, <LENGTH_CM>, <LENGTH_MM>, <LENGTH_IN>, <LENGTH_PT>, <LENGTH_PC>, <ANGLE_DEG>, <ANGLE_RAD>, <ANGLE_GRAD>, <TIME_MS>, <TIME_S>, <FREQ_HZ>, <FREQ_KHZ>, <RESOLUTION_DPI>, <RESOLUTION_DPCM>, <PERCENTAGE>, <DIMENSION>, <UNICODE_RANGE>, <URI>, <FUNCTION>, "progid:".)
Oct 29, 2018 6:22:29 PM com.gargoylesoftware.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://amzscout.net/css/common.css' [1:12280] Error in expression. (Invalid token " ". Was expecting one of: <NUMBER>, "inherit", <IDENT>, <STRING>, <HASH>, <EMS>, <EXS>, <LENGTH_PX>, <LENGTH_CM>, <LENGTH_MM>, <LENGTH_IN>, <LENGTH_PT>, <LENGTH_PC>, <ANGLE_DEG>, <ANGLE_RAD>, <ANGLE_GRAD>, <TIME_MS>, <TIME_S>, <FREQ_HZ>, <FREQ_KHZ>, <RESOLUTION_DPI>, <RESOLUTION_DPCM>, <PERCENTAGE>, <DIMENSION>, <UNICODE_RANGE>, <URI>, <FUNCTION>, "progid:".)
Oct 29, 2018 6:22:29 PM com.gargoylesoftware.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://amzscout.net/css/common.css' [1:23006] Error in @media rule. (Invalid token "@font-face". Was expecting one of: <S>, <IDENT>, "}", ".", ":", "*", "[", <HASH>, <IMPORT_SYM>, <PAGE_SYM>, <MEDIA_SYM>, <ATKEYWORD>.)
Oct 29, 2018 6:22:29 PM com.gargoylesoftware.htmlunit.DefaultCssErrorHandler warning
WARNING: CSS warning: 'https://amzscout.net/css/common.css' [1:23006] Ignoring the whole rule.
Oct 29, 2018 6:22:29 PM com.gargoylesoftware.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://amzscout.net/css/common.css' [1:23135] Error in rule. (Invalid token "}". Was expecting one of: <S>, <IDENT>, "<!--", "-->", ".", ":", "*", "[", <HASH>, <IMPORT_SYM>, <PAGE_SYM>, <MEDIA_SYM>, <FONT_FACE_SYM>, <ATKEYWORD>.)
Oct 29, 2018 6:22:29 PM com.gargoylesoftware.htmlunit.DefaultCssErrorHandler warning
WARNING: CSS warning: 'https://amzscout.net/css/common.css' [1:23135] Ignoring the whole rule.
Oct 29, 2018 6:22:29 PM com.gargoylesoftware.htmlunit.DefaultCssErrorHandler error
WARNING: CSS error: 'https://amzscout.net/css/common.css' [2:45659] Error in expression. (Invalid token " ". Was expecting one of: <NUMBER>, "inherit", <IDENT>, <STRING>, <HASH>, <EMS>, <EXS>, <LENGTH_PX>, <LENGTH_CM>, <LENGTH_MM>, <LENGTH_IN>, <LENGTH_PT>, <LENGTH_PC>, <ANGLE_DEG>, <ANGLE_RAD>, <ANGLE_GRAD>, <TIME_MS>, <TIME_S>, <FREQ_HZ>, <FREQ_KHZ>, <RESOLUTION_DPI>, <RESOLUTION_DPCM>, <PERCENTAGE>, <DIMENSION>, <UNICODE_RANGE>, <URI>, <FUNCTION>, "progid:".)
Oct 29, 2018 6:22:30 PM com.gargoylesoftware.htmlunit.IncorrectnessListenerImpl notify
WARNING: Obsolete content type encountered: 'text/javascript'.
Oct 29, 2018 6:22:31 PM com.gargoylesoftware.htmlunit.IncorrectnessListenerImpl notify
WARNING: Obsolete content type encountered: 'application/x-javascript'.
Oct 29, 2018 6:22:31 PM com.gargoylesoftware.htmlunit.IncorrectnessListenerImpl notify
WARNING: Obsolete content type encountered: 'application/x-javascript'.
Oct 29, 2018 6:22:32 PM com.gargoylesoftware.htmlunit.html.HtmlScript isExecutionNeeded
WARNING: Script is not JavaScript (type: application/ld+json, language: ). Skipping execution.
Oct 29, 2018 6:22:33 PM com.gargoylesoftware.htmlunit.javascript.host.css.CSSStyleSheet isValidCondition
WARNING: Unhandled CSS condition type 'PREFIX_ATTRIBUTE_CONDITION'. Accepting it silently.
Oct 29, 2018 6:22:33 PM com.gargoylesoftware.htmlunit.javascript.StrictErrorReporter runtimeError
SEVERE: runtimeError: message=[An invalid or illegal selector was specified (selector: '*,:x' error: Invalid selector: *:x).] sourceName=[https://amzscout.net/js/common.js] line=[1] lineSource=[null] lineOffset=[0]

Answer 1

更具体地说明您的搜索条件，有两个具有类名的 div：'cat-pick_list'，第二个是空的。

注意： 开始使用 css 选择器和 xpath（仅当 css 选择器没有帮助时），最好的选择是 id。

试试

WebElement pickList = driver.findElement(By.cssSelector(".container > .cat-pick_list"));
.....
List<WebElement> elements = pickList.findElements(By.cssSelector(".cat-pick_i"));

结果：

类别数量：30 电器 艺术、工艺和缝纫 汽车 婴儿美容和个人护理书籍相机和照片手机和 配饰 服装、鞋履和珠宝 电脑和配饰 电子 杂货与美食 健康与家居 家居与园艺 家居与厨房 工业与科学首饰 Kindle Store Kitchen & 餐饮 乐器 办公用品 露台、草坪和花园 宠物 用品 鞋类 软件 运动与户外 工具与家居装饰 玩具和游戏手表视频游戏

Answer 2

或者你可以直接试试这个：

List<WebElement> elements = pickList.findElements(By.cssSelector(".container > .cat-pick_list > .cat-pick_i"));

我认为这应该可行。