Question

import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.chrome.ChromeDriver;
import java.text.ParseException;
import java.util.List;
import org.openqa.selenium.WebElement;

    public class WebTable {


    public static void main(String args[])throws ParseException{
    WebDriver wd;
    System.setProperty("webdriver.chrome.driver","E:\\Selenium-2017\\chromedriver_win32\\chromedriver.exe");

    wd = new ChromeDriver();
    wd.get("http://money.rediff.com/gainers/bsc/daily/groupa");

    List<WebElement> col = (List<WebElement>) wd.findElement(By.xpath(".//*[@id='leftcontainer']/table/thead/tr/th"));
    System.out.println("No of cols are : " +col.size());
     List<WebElement> rows = (List<WebElement>) wd.findElement(By.xpath(".//*[@id='leftcontainer']/table/tbody/tr[1]/td[1]"));
     System.out.println("No of rows are :" +rows.size());
     wd.close();
    }
    }

获得以下异常：

Starting ChromeDriver 2.29.461591 (62ebf098771772160f391d75e589dc567915b233) on port 44959
Only local connections are allowed.
log4j:WARN No appenders could be found for logger (org.apache.http.client.protocol.RequestAddCookies).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
Exception in thread "main" java.lang.ClassCastException: org.openqa.selenium.remote.RemoteWebElement cannot be cast to java.util.List
    at WebTable.main(WebTable.java:17)

Answer 1

findElement返回WebElement，无法转换为WebElements列表。移除广告(List<WebElement>)并使用findElements()（使用＆＃39; s＆＃39;）代替。

请参阅此SO question和此tutorial

Answer 2

以下是您的问题的答案：

您必须按照以下方式处理以下几项事项：

您正在尝试findElement()，而wd.findElement(By.xpath(".//*[@id='leftcontainer']/table/thead/tr/th"));只会返回一个 WebElement。接下来，您尝试将WebElement转换为List<WebElement>，Java编译器正在抱怨 Type safety: Unchecked cast from WebElement to List<WebElement> 。见下面的快照：

因此，我们将使用(List<WebElement>) wd.findElement(By.xpath(".//*[@id='leftcontainer']/table/thead/tr/th"));方法而不是像findElements()中那样进行转换，而是直接创建List<WebElement>，如下所示：
```
List<WebElement> col = wd.findElements(By.xpath(".//*[@id='leftcontainer']/table/thead/tr/th"));
```
我们也会对List<WebElement> rows采用相同的方法，但我们必须更改xpath以获得rows的计数，如下所示：
```
List<WebElement> rows = wd.findElements(By.xpath(".//*[@id='leftcontainer']/table/tbody/tr/td/a"));
```

因此，您的最终代码块将如下所示：

package demo;

import java.util.List;

import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.chrome.ChromeDriver;

public class Q45393541_rediff {

    public static void main(String[] args) {


        WebDriver wd;
        System.setProperty("webdriver.chrome.driver", "C:\\Utility\\BrowserDrivers\\chromedriver.exe");
        wd = new ChromeDriver();
        wd.get("http://money.rediff.com/gainers/bsc/daily/groupa");
        List<WebElement> cols = wd.findElements(By.xpath(".//*[@id='leftcontainer']/table/thead/tr/th"));
        System.out.println("No of cols are : " +cols.size());
        List<WebElement> rows = wd.findElements(By.xpath(".//*[@id='leftcontainer']/table/tbody/tr/td/a"));
        System.out.println("No of rows are :" +rows.size());
        wd.close();

    }

}

控制台上的输出为：
```
No of cols are : 5
No of rows are :182
```

如果这回答你的问题，请告诉我。

java.lang.ClassCastException同时从Dynamic Webtable中获取行数和列数

2 个答案: