Cannot cast from List to List creating a list from list of WebElements using Selenium and stream() Java8

问题

I'm trying to read an HTML table and get all the values into a 2d list using selenium. I'm using streamable to create a List inside another map() method. But I get Cannot cast from List<Functions.Function1<Object,String>> to List<String> error at nested collect method's line

HTML:

+--------+-------+
| r1 v1  | r1 v2 |
+--------+-------+
| r2 v1  | r2 v2 |
+--------+-------+

<html>
    <body>
        <table>
            <tbody>
                <tr>
                    <td>
                        <div>
                            <span>r1 v1</span>
                        </div>
                    </td>
                    <td>
                        <div>
                            <span>r1 v2</span>
                        </div>
                    </td>
                </tr>
                <tr>
                    <td>
                        <div>
                            <span>r2 v1</span>
                        </div>
                    </td>
                    <td>
                        <div>
                            <span>r2 v2</span>
                        </div>
                    </td>
                </tr>
            </tbody>
        </table>
    </body>
</html>

Java Code:

public List getTableData() {
    return webElement
            .findElements(By.xpath(".//table/tbody/tr"))
            .stream()
            .map(row -> {
                return row
                    .findElements(By.xpath(".//td/div/span"))
                    .stream()
                    .map(cell -> {
                        return cell
                            .getAttribute("innerText");
                    })
                    .collect(Collectors.toList()); // : Cannot cast from List<Functions.Function1<Object,String>> to List<String>
            })
            .collect(Collectors.toList());
}

Why am I gettting this error? How can I create a 2d List out of this table using java streamable?

回答1:

To create a List with the innerText using Java8's stream() and map() you can use the following solution:

cssSelector:

List<String> myTexts = new WebDriverWait(driver, 20).until(ExpectedConditions.visibilityOfAllElementsLocatedBy(By.cssSelector("table>tbody tr td span"))).stream().map(element->element.getAttribute("innerHTML")).collect(Collectors.toList());

xpath:

List<String> myTexts = new WebDriverWait(driver, 20).until(ExpectedConditions.visibilityOfAllElementsLocatedBy(By.xpath("//table/tbody//tr//td//span"))).stream().map(element->element.getAttribute("innerHTML")).collect(Collectors.toList());

References: You can find a couple of relevant discussions in:

How to extract the dynamic values of the id attributes of the table elements using Selenium and Java

How to print all the button texts within the url using Selenium through Java

来源：https://stackoverflow.com/questions/57520786/cannot-cast-from-listfunctions-function1object-string-to-liststring-creati

标签

java