Question

在触发测试时，尝试与Page Factory WebElement进行交互时，似乎看到了空指针异常。

我的DriverFactory中包含的代码：

public class DriverFactory {
    private static DriverFactory instance = null;
    public static ThreadLocal<WebDriver> webDriver = new ThreadLocal<WebDriver>();

    public static DriverFactory getInstance() {
        if ( instance == null ) {
            instance = new DriverFactory();
        }
        return instance;
    }

    public static final void setDriver(String browser) {
        switch (browser) {

        case "firefox":
                System.setProperty("webdriver.gecko.driver", 
                Global_VARS.FIREFOX_DRIVER_DIRECTORY);
                webDriver.set(new FirefoxDriver());
            break;

        case "chrome":
                System.setProperty("webdriver.chrome.driver", 
                Global_VARS.CHROME_DRIVER_DIRECTORY);
                webDriver.set(new ChromeDriver());
            break;
        }
        getDriver().manage().timeouts().implicitlyWait(20, TimeUnit.SECONDS);
        getDriver().manage().window().maximize();
    }

    public static WebDriver getDriver() {
        return webDriver.get();
    }

    public static void tearDown() {
        getDriver().quit();
    }
}

我的base页中包含的代码：

public abstract class BasePO<T>  {
    private @FindBy(xpath = "//a[text()='Log in']") WebElement logIn_button;
    protected WebDriver driver;

    public BasePO() {
        this.driver = DriverFactory.getDriver();
        PageFactory.initElements(this.driver, this);
    }

    public void openHomepage() {
        driver.get("https://stackoverflow.com/");
    }

    public void baseClickOnLoginButton() {
        logIn_button.click();
    }
}

我的BaseTest类中包含的代码：

public class BaseTest {
    public SubPage subPage;
    public BasePO<?> basePage;

    @BeforeClass
    public void pomSetup() {
        subPage = PageFactory.initElements(DriverFactory.getDriver(), SubPage.class);
        basePage = PageFactory.initElements(DriverFactory.getDriver(), BasePO.class);
    }

    @BeforeMethod
    public void setup() {
        DriverFactory.setDriver("chrome");

        //works
        //subPage.openHomepage();
    }

    @AfterMethod
    public void tearDown() {
        if (DriverFactory.getDriver() != null) {
            DriverFactory.tearDown();
        }
    }

构成我的测试用例的代码：

public class Test1 extends BaseTest {
    @Test
    public void exampleTest1() throws InterruptedException {
        subPage.openHomepage(); //works as expected

        subPage.clickOnLoginButton(); //Exception here, null pointer 
    }
}

当触发我的TestNg测试其openHomePage方法有效时，依次打开指定的url；在尝试单击DriverFactory.getDriver().get()元素（例如在测试中调用：Page Factory）时使用logIn_button.click();的元素，即使我已初始化该类，我似乎仍收到空指针异常？ / p>

Answer 1

在@BeforeClass中，已在创建驱动程序实例之前初始化了Page工厂。如果在NAME: AKIO R. USERNAME: ariggins SECLEVEL: 4 Menu: HELP > TIME ENTRY > MESSAGES HELP > ABOUT > ABOUT HELP > CHANGE PASSWORD > CHANGE PASSWORD ..... NAME: THE NEXT EMPLOYEE USERNAME: EMPLOYEE USERNAME SECLEVEL: 6 MENU: HELP > TIME ENTRY > TIME ENTRY HELP > ABOUT > ABOUT HELP > AD-HOC > AD-HOC ....CONTINUES UNTIL COMPLETE之后将pomSetup()中的代码移至setup()方法中，则测试代码应该可以工作。另外，在DriverFactory.setDriver("chrome");类中，您已经在构造函数中初始化了页面工厂，因此在BasePO类中调用new就足够了。

BaseTest

Answer 2

在代码部分，有一些建议。

DriveFactory的实现是错误的。您正在使用从未使用过的单例初始化。而是将代码更改为下面的代码。

public class DriverFactory {
    private static DriverFactory instance = null;
    // Singleton initialization
    public static DriverFactory getInstance() {
        if ( instance == null ) 
            instance = new DriverFactory();
        return instance;
    }

    public ThreadLocal<WebDriver> webDriver = new ThreadLocal<WebDriver>();

    public final void setDriver(String browser) {
        switch (browser) {
            case "firefox":
                System.setProperty("webdriver.gecko.driver", Global_VARS.FIREFOX_DRIVER_DIRECTORY);
                webDriver.set(new FirefoxDriver());
                break;
            case "chrome":
                System.setProperty("webdriver.chrome.driver", Global_VARS.CHROME_DRIVER_DIRECTORY);
                webDriver.set(new ChromeDriver());
                break;
        }
        getDriver().manage().timeouts().implicitlyWait(20, TimeUnit.SECONDS);
        getDriver().manage().window().maximize();
    }

    public WebDriver getDriver() {
        return webDriver.get();
    }

    public void tearDown() {
        getDriver().quit();
    }
}

页面对象模型在运行测试时看到空指针异常？

2 个答案: