在页面对象模型上出现nullpointerexception错误

Question

嗨，伙计们，我跟随页面对象模型在Java与黄瓜。我有以下类:

AbstractClass.java:发起webdriver实例，作为其他对象类的Master类。

package ObjectRepository;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.Properties;
import java.util.concurrent.TimeUnit;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.firefox.FirefoxDriver;

/**
 * Hello world!
 *
 */
public class AbstractClass {
    public static WebDriver driver=null;
    Properties p = new Properties();   // create an object of properties
    public AbstractClass(WebDriver driver){
        this.driver=driver;
    }
    public void setup() throws IOException{
        // file input stream obect
        FileInputStream fi= new FileInputStream("C:\Users\sulemanmazhar\Google Drive\Automation Learning\Java\udemyWorkspace\DebitCard_PageObject\src\test\java\Banking\global.properties");
        p.load(fi); // load the properties
        if (p.getProperty("browser").contains("fireFox")){  // if browser in property file is firefox
            driver=new FirefoxDriver();         
        };  
        driver.manage().timeouts().implicitlyWait(20, TimeUnit.SECONDS);
    }

    public loginPage navigateToWelcomePage(){
        String url=p.getProperty("url");
        System.out.println(url);
        driver.navigate().to(url);
        return new loginPage(driver);
    }
    public String getTitle(){
        String title= driver.getTitle().trim();
        return title;
    }
    public void quitDriver(){
        driver.quit();
    }
}

loginPage.Java:作为我的SUT登录页的对象存储库类。继承抽象类

      package ObjectRepository;
    import org.openqa.selenium.By;
    import org.openqa.selenium.WebDriver;

    /**
     * This class is within the object repository package
     * This package will contain all the objects which will
     * These objects will be stored and the will be accessed from the test/java folder

    public class loginPage extends AbstractClass 
        public loginPage(WebDriver driver){
            super(driver);
        }
        // all login page objects belong to this page
        By username = By.name("userName");   // object
        By password = By.name("password");
        By name= By.name("login");  
        By registerLink = By.linkText("REGISTER");
        By signInLink=By.linkText("SIGN-ON");
    // constructor passes a webdriver object    
        public flightFinder login(String userId,String passw){
            driver.findElement(username).sendKeys(userId);
            driver.findElement(password).sendKeys(passw);
            driver.findElement(name).click();
            return new flightFinder(driver);
           }

        public registerPage navigateToRegister() {
            driver.findElement(registerLink).click();
            return new registerPage(driver);
        }
        public loginPage navigateToSignOn(){
       driver.findElement(signInLink).click();
            return new loginPage(driver);   
        }
}

我也有registerPage.java，flighFinder.java，它的作用与loginPage.java

对于每个类我都有相应的测试类。我想讨论的两个类是:

stepsdefinition .java:该类包含了大多数适用于不同类的常用方法。

package TestClasses;
import java.io.IOException;
import org.openqa.selenium.WebDriver;
import org.testng.Assert;
import org.testng.annotations.AfterMethod;
import org.testng.annotations.AfterTest;
import ObjectRepository.flightFinder;
import ObjectRepository.loginPage;
import ObjectRepository.registerPage;
import cucumber.api.java.After;
import cucumber.api.java.Before;
import cucumber.api.java.en.Given;
import cucumber.api.java.en.Then;
import cucumber.api.java.en.When;
public class StepsDefinition {
    WebDriver  driver;
    loginPage loginPage;
    //flightFinder flightFinder;
    registerPage registerPage;

    @Before
    public void setUp() throws IOException{
        System.out.println("Executing before method");
        loginPage = new loginPage(driver);
        loginPage.setup();
        loginPage.navigateToWelcomePage();
    }
    @After
    public void CloseDriver(){
        System.out.println("Executing after method");
        loginPage.quitDriver();
    }
    /* Shared steps */
    @Given("^I am on "([^"]*)" page$")
    public void i_am_on_page(String page) {
    if(page.equalsIgnoreCase("sign-on")){
            loginPage=loginPage.navigateToSignOn();
        }   
    if(page.equalsIgnoreCase("register")){
        registerPage=loginPage.navigateToRegister();
        }   
        String Title =loginPage.getTitle();
        System.out.println("Actual page title is :"+ Title+" Expected Title is :"+page);
        Assert.assertTrue(Title.contains(page));
    }
    @When("^I click on "([^"]*)" button$")
    public void i_click_on_button(String button) {
        if (button.equalsIgnoreCase("register")){
            registerPage=loginPage.navigateToRegister();    
        }
        else if(button.equalsIgnoreCase("sign-on")){
            loginPage=loginPage.navigateToSignOn();
        }
    }
    @Then("^I should be navigated to "([^"]*)" page$")
    public void i_should_be_navigated_to_page(String page) {
        String Title =loginPage.getTitle().trim();
        System.out.println("Actual page is :"+Title +" Expected page is :"+page);
        Assert.assertTrue(Title.contains(page));
    }
}

logntest.java :是包含测试登录页代码的测试类。包TestClasses;

import org.openqa.selenium.WebDriver;
import ObjectRepository.flightFinder;
import ObjectRepository.loginPage;
import ObjectRepository.registerPage;
import cucumber.api.java.en.Given;
import cucumber.api.java.en.When;
public class LoginTest {
    //WebDriver  driver;
    loginPage loginPage;
    flightFinder flightFinder;
    registerPage registerPage;
    /* Login Page */
    @When("^I input my details as "([^"]*)" and "([^"]*)"$")
    public void i_input(String username, String password) {
        flightFinder=loginPage.login(username,password);
    }
    @Given("^I am logged in as "([^"]*)" and "([^"]*)"$")
    public void i_am_logged_in(String username, String password){
    flightFinder=loginPage.login(username,password);
    }
}

好的，我的问题是:当我执行测试时，StepsDefinition.java中的所有测试都运行良好，如预期的那样。一旦它移动到 logtests . java ，我得到以下错误:

5 Scenarios ([31m3 failed[0m, [32m2 passed[0m)
16 Steps ([31m3 failed[0m, [36m5 skipped[0m, [32m8 passed[0m)
1m30.444s
java.lang.NullPointerException
    at TestClasses.LoginTest.i_am_logged_in(LoginTest.java:30)
    at ✽.Given I am logged in as "test" and "test"(featureFiles/flightFinder.feature:5)
java.lang.NullPointerException
    at TestClasses.LoginTest.i_input(LoginTest.java:23)
    at ✽.When I input my details as "test" and "test"(featureFiles/login.feature:12)
java.lang.NullPointerException
    at TestClasses.Register_Test.i_input_my_details(Register_Test.java:21)
    at ✽.When I input my details(featureFiles/register.feature:12)

我认为发生的事情是，我在stepsDefinition.Java类中初始化对象，一旦测试移动到另一个测试类，它就不会继续使用对象的先前状态。

如果是这种情况，我如何将一个对象的状态传递给另一个对象?如果不是，那么我错在哪里?

Answer 1

WebDriver在抽象类中实例化。

在loginPage.Java,registerPage.java,flighFinder.java中，您正在使用未实例化的驱动程序或在抽象类中实例化的驱动程序未传递给这些类。

解决方法:Remove driver=new FirefoxDriver();从抽象类的设置，而不是把它放在LoginTest和传递驱动程序对象在loginPage,registerPage对象的创建。

ex: WebDriver = new ChromeDriver();loginPage = new loginPage(driver);

我已经试过了。