java - 在 Selenium 中使用 findElements 的 NullpointerException 和 alter 未处理

Question

1. 当我将 findElements 方法与列表一起使用时，出现 NullPointerException。尝试使用 POM 模型也得到相同的错误。评论了代码的 findelements 部分并测试它工作正常。我不确定我的代码有什么问题。

2. 代码中定义的警报未处理位置警报，未出现任何更改发现异常。

我的代码需要修复什么？

代码:

import java.util.ArrayList;
import java.util.List;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import org.openqa.selenium.By;
import org.openqa.selenium.Keys;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.chrome.ChromeDriver;
import org.openqa.selenium.firefox.FirefoxDriver;
import org.openqa.selenium.interactions.Action;
import org.openqa.selenium.interactions.Actions;
import org.openqa.selenium.support.FindBy;
import org.openqa.selenium.support.How;
import org.openqa.selenium.support.ui.ExpectedConditions;
import org.openqa.selenium.support.ui.Select;
import org.openqa.selenium.support.ui.WebDriverWait;

class CleartripPOM1 {
    WebDriver driver;
    private String url="https://www.cleartrip.com/";
    public CleartripPOM1(WebDriver driver) {
        this.driver=driver;
}

By from=By.xpath("//input[@title='Any worldwide city or airport' and @etitle='From']");
By to=By.xpath("//input[@title='Any worldwide city or airport' and @etitle='To']");
By date=By.xpath("//input[@id='DepartDate']");
By adults=By.id("Adults");
By childerns=By.cssSelector("select[name='childs'][id='Childrens']" );
By infants=By.name("infants");
By search=By.xpath("//input[@id='SearchBtn']");
By airline=By.xpath("//li[@class='vendor']/a");
By depart=By.xpath("//li[@class='depart']/a");
By duration=By.xpath("//li[@class='duration']/a");
By price=By.xpath("//li[@class='price']/a");
private List <WebElement>coupon =driver.findElements(By.xpath("//ul[@class='listView flights']/li/table/tbody/tr/td/span"));
private List <WebElement> airName=driver.findElements(By.xpath("//ul[@class='listView flights']/li/table/tbody/tr/th/small"));
private List <WebElement> departure=driver.findElements(By.xpath("//ul[@class='listView flights']/li/table/tbody/tr/th[@class='depart']"));
private List <WebElement> arrival=driver.findElements(By.xpath("//ul[@class='listView flights']/li/table/tbody/tr/th[@class='arrive']"));
private List <WebElement> travelTime=driver.findElements(By.xpath("//ul[@class='listView flights']/li/table/tbody/tr/th[@class='duration']"));
private List <WebElement> ticketFare=driver.findElements(By.xpath("//ul[@class='listView flights']/li/table/tbody/tr/th[@class='price']"));

public ArrayList<String> airlineNames(List<WebElement>el) {
    ArrayList<String> names= new ArrayList<String>();
    for(WebElement e:el) {
        names.add(e.getText());
    }
    return names;
}

public void url_launch() {
    driver.get(url);
    driver.manage().window().maximize();
//  WebDriverWait wait= new WebDriverWait(driver,20);
//  wait.until(ExpectedConditions.alertIsPresent());
//  Alert alert = driver.switchTo().alert();
//  alert.dismiss();

}
public void actions(By e, String location) {
    Actions act = new Actions(driver);
    Action action= act.click(driver.findElement(e)).sendKeys(location).build();
    action.perform();
}

public void selection(By e,String selection) {
    Select select = new Select(driver.findElement(e));
    select.selectByValue(selection);

}
public void searchFlights() {
    actions(from,"Chennai");
    actions(to,"Madurai");
    actions(date,"25/08/2018");
    driver.findElement(date).sendKeys(Keys.TAB);
    selection(adults,"2");
    selection(childerns,"3");
    selection(infants,"1");
    driver.findElement(search).click();
    WebDriverWait wait= new WebDriverWait(driver,20);
    wait.until(ExpectedConditions.presenceOfElementLocated(By.xpath("//li[@class='vendor']/a")));
    System.out.println(airlineNames(coupon));
    System.out.println(airlineNames(airName));
    System.out.println(airlineNames(departure));
    System.out.println(airlineNames(arrival));
    System.out.println(airlineNames(travelTime));
    System.out.println(airlineNames(ticketFare));

运行代码:

public class TestRunner {

    public static void main(String[] args) {
        WebDriver driver = new ChromeDriver();
        // TODO Auto-generated method stub
        CleartripPOM1 ct= new CleartripPOM1(driver);
        ct.url_launch();
        ct.searchFlights();
    }
}

Answer 1

#1:您在初始化 driver 变量之前初始化所有实例 Web 元素，因此它会抛出 NullPointerException。实例 Web 元素初始化需要移至构造函数内，否则需要移至需要该特定元素的方法内。

我给出了两种带有两个元素示例的方法。请使用以下任一方法更改所有实例元素初始化。

例如:

方法一:在构造函数中初始化实例WebElement。这样，所有WebElement都可以在类中的所有方法中访问。

    WebDriver driver;

    private List <WebElement>coupon;
    private List <WebElement> airName;
    private String url="https://www.cleartrip.com/";
    public CleartripPOM1(WebDriver driver) {
        this.driver=driver;
        coupon=driver.findElements(By.xpath("//ul[@class='listView flights']/li/table/tbody/tr/td/span"));
        airName=driver.findElements(By.xpath("//ul[@class='listView flights']/li/table/tbody/tr/th/small"));
        -----------
        ----------- and so on

    }

方法 2: 仅在需要的方法内初始化 WebElement 实例。假设您只想在某个方法中访问优惠券和航空名称元素列表，那么您可以单独在该特定方法中进行初始化

    WebDriver driver;

    private List <WebElement>coupon;
    private List <WebElement> airName;
    private String url="https://www.cleartrip.com/";
    public CleartripPOM1(WebDriver driver) {
        this.driver=driver;

    }

    public void travelDetails(){
        coupon=driver.findElements(By.xpath("//ul[@class='listView flights']/li/table/tbody/tr/td/span"));
        airName=driver.findElements(By.xpath("//ul[@class='listView flights']/li/table/tbody/tr/th/small"));
         -----------
         ----------- and so on

   }

#2 关于警报，您将收到 chrome 特定通知。因此，您需要在驱动程序初始化部分禁用通知选项，如下所示

    ChromeOptions options = new ChromeOptions();
    options.addArguments("--disable-notifications");
    WebDriver driver=new ChromeDriver(options);

编辑:

解决后续问题:

仅执行搜索操作后，您将获得结果部分，并且从结果部分中识别出所有列表 WebElement。因此，您需要在执行搜索操作后初始化所有列表 WebElement，如下所示。

关于Web元素声明，如果您想在不同的方法中访问相同的WebElement，那么您可以将WebElement声明为实例。如果List WebElement范围仅在searchFlights方法中，那么我建议在searchFlights 方法而不是实例声明。

搜索方法需要更改:

public void searchFlights() {
    actions(from,"Chennai");
    actions(to,"Madurai");
    actions(date,"25/08/2018");
    driver.findElement(date).sendKeys(Keys.TAB);
    selection(adults,"2");
    selection(childerns,"3");
    selection(infants,"1");
    driver.findElement(search).click();
    WebDriverWait wait= new WebDriverWait(driver,20);
    wait.until(ExpectedConditions.presenceOfElementLocated(By.xpath("//li[@class='vendor']/a")));

    coupon =driver.findElements(By.xpath("//ul[@class='listView flights']/li/table/tbody/tr/td/span"));
    airName=driver.findElements(By.xpath("//ul[@class='listView flights']/li/table/tbody/tr/th/small"));
    departure=driver.findElements(By.xpath("//ul[@class='listView flights']/li/table/tbody/tr/th[@class='depart']"));
    arrival=driver.findElements(By.xpath("//ul[@class='listView flights']/li/table/tbody/tr/th[@class='arrive']"));
    travelTime=driver.findElements(By.xpath("//ul[@class='listView flights']/li/table/tbody/tr/th[@class='duration']"));
    ticketFare=driver.findElements(By.xpath("//ul[@class='listView flights']/li/table/tbody/tr/th[@class='price']"));


    System.out.println(airlineNames(coupon));
    System.out.println(airlineNames(airName));
    System.out.println(airlineNames(departure));
    System.out.println(airlineNames(arrival));
    System.out.println(airlineNames(travelTime));
    System.out.println(airlineNames(ticketFare));


}