Java 如何扩展Selenium By.class以创建更大的灵活性？

如何通过.class扩展Selenium，以创建更大的灵活性？我看了一下，我不太知道如何处理这个问题。看起来我需要创建一个接口类和一个静态By类，比如ByJavascriptGetWebElement，以便创建这种包装器

我希望能够这样称呼它：

By.javascript("return document.querySelector(\"div#item div\");", el );

我也听说过一种更简单的方法，但我更喜欢用更传统的方法：

public By byJavascriptGetElement( WebElement we ) {
    return By.  ???
}

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有什么想法吗？

这其实很容易做到

其思想是访问

WebDriver

实例并在其上运行JavaScript（如果它支持的话）。然后是大量的验证，因为我们需要确保只归还我们承诺的东西

ByJavaScript

类本身如下所示：

public class ByJavaScript extends By implements Serializable {
    private final String script;

    public ByJavaScript(String script) {
        checkNotNull(script, "Cannot find elements with a null JavaScript expression.");
        this.script = script;
    }

    @Override
    public List<WebElement> findElements(SearchContext context) {
        JavascriptExecutor js = getJavascriptExecutorFromSearchContext(context);

        // call the JS, inspect and validate response
        Object response = js.executeScript(script);
        List<WebElement> elements = getElementListFromJsResponse(response);

        // filter out the elements that aren't descendants of the context node
        if (context instanceof WebElement) {
            filterOutElementsWithoutCommonAncestor(elements, (WebElement)context);
        }

        return elements;
    }

    private static JavascriptExecutor getJavascriptExecutorFromSearchContext(SearchContext context) {
        if (context instanceof JavascriptExecutor) {
            // context is most likely the whole WebDriver
            return (JavascriptExecutor)context;
        }
        if (context instanceof WrapsDriver) {
            // context is most likely some WebElement
            WebDriver driver = ((WrapsDriver)context).getWrappedDriver();
            checkState(driver instanceof JavascriptExecutor, "This WebDriver doesn't support JavaScript.");
            return (JavascriptExecutor)driver;
        }
        throw new IllegalStateException("We can't invoke JavaScript from this context.");
    }

    @SuppressWarnings("unchecked")  // cast thoroughly checked
    private static List<WebElement> getElementListFromJsResponse(Object response) {
        if (response == null) {
            // no element found
            return Lists.newArrayList();
        }
        if (response instanceof WebElement) {
            // a single element found
            return Lists.newArrayList((WebElement)response);
        }
        if (response instanceof List) {
            // found multiple things, check whether every one of them is a WebElement
            checkArgument(
                    Iterables.all((List<?>)response, Predicates.instanceOf(WebElement.class)),
                    "The JavaScript query returned something that isn't a WebElement.");
            return (List<WebElement>)response;  // cast is checked as far as we can tell
        }
        throw new IllegalArgumentException("The JavaScript query returned something that isn't a WebElement.");
    }

    private static void filterOutElementsWithoutCommonAncestor(List<WebElement> elements, WebElement ancestor) {
        for (Iterator<WebElement> iter = elements.iterator(); iter.hasNext(); ) {
            WebElement elem = iter.next();

            // iterate over ancestors
            while (!elem.equals(ancestor) && !elem.getTagName().equals("html")) {
                elem = elem.findElement(By.xpath("./.."));
            }

            if (!elem.equals(ancestor)) {
                iter.remove();
            }
        }
    }

    @Override
    public String toString() {
          return "By.javaScript: \"" + script + "\"";
    }

}

现在，原始的

By

类是一个静态工厂，它提供了自身的各种实现。不幸的是，我们无法向其中添加新的静态方法（不更改其源代码），因此我们无法通过.javascript（“return something；”）键入

By.javascript

。我们必须创建自己的静态工厂，以获得类似的结果：

public class MyBy {
    /**
     * Returns a {@code By} which locates elements by the JavaScript expression passed to it.
     * 
     * @param script The JavaScript expression to run and whose result to return
     */
    public static By javascript(String script) {
        return new ByJavaScript(script);
    }
}

用法：

WebElement elem = driver.findElement(new ByJavaScript("return document.querySelector('.haha');"));

WebElement elem = driver.findElement(MyBy.javascript("return document.querySelector('.haha');"));

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谢谢你。这就是我一直在寻找的答案。你的答案中有很多东西是有道理的，但如果不花很多时间，我是不会想到的。我很感激你的回答。没问题。我喜欢传播知识！如果您有任何其他问题，请随时提问。我认为编写一个更具体的类会很有用，比如“ByJquery”。@djangofan-Yeah。像这样-？：）