Selenium webdriver 运行Selenium测试脚本时获取NullPointeException

在执行下面的testng测试脚本之后，我得到了NullPointerException。当URL进入测试脚本方法时，启动URL后，它将抛出异常。你能帮我解决这个问题吗

（对象回购）LakesAndMountainsHomePage.java:-

import org.openqa.selenium.WebElement;
import org.openqa.selenium.support.FindBy;
import org.openqa.selenium.support.PageFactory;
import com.actitime.genericlib.WebDriverCommonLib;

public class LakesAndMountainsHomePage extends WebDriverCommonLib{

WebDriver driver;

public LakesAndMountainsHomePage(WebDriver driver)
{
this.driver = driver;
PageFactory.initElements(driver, this);
}


@FindBy(xpath= "//*[@id='the-main-menu']//*[contains(text() , 'LAKES & 
MOUNTAINS')]")
WebElement LandM;

public WebElement LandMHeader()
{
System.out.println("came inside the method");
//LandM.isDisplayed();
return LandM;
}

}

public abstract class BaseTest {

    ExcelLib eLib;
    WebDriverCommonLib wLib;
    WebDriver driver;
    HomePage homepage;

  @BeforeClass
  public void baseBeforeClass() 
  {
    eLib = new ExcelLib();
    wLib = new WebDriverCommonLib();
    driver=Driver.getBrowser();
    driver.manage().window().maximize();
    System.out.println("Browser is launched");
  }

  @BeforeMethod
  public void launchURL()
  {  
      wLib.homePage();
      //loginPage.loginToAPP();
      System.out.println("Navigated to the URL");
  }      
}

public class LakesAndMountainsHomePageTest extends BaseTest{

LakesAndMountainsHomePage lm = new LakesAndMountainsHomePage(this.driver);

 //TC TC131409 [New Lakes & Mountains Tab] : Verify New Lakes & Mountains 
Tab is displayed in header. 
 @Test(priority=0)
  public void lakesAndMountainsHeader()
  {
boolean a= lm.LandMHeader().isDisplayed(); //getting exception here
if(a==true)
{
System.out.println("Lakes And Mountains tab is present in the HomePage");
}
else
{
System.out.println("Lakes And Mountains tab is not present in the 
HomePage");
}
      lm.LandMHeader().click(); 
      System.out.println("It has clicked the tab");
  }
}

BaseTest.java:-

import org.openqa.selenium.WebElement;
import org.openqa.selenium.support.FindBy;
import org.openqa.selenium.support.PageFactory;
import com.actitime.genericlib.WebDriverCommonLib;

public class LakesAndMountainsHomePage extends WebDriverCommonLib{

WebDriver driver;

public LakesAndMountainsHomePage(WebDriver driver)
{
this.driver = driver;
PageFactory.initElements(driver, this);
}


@FindBy(xpath= "//*[@id='the-main-menu']//*[contains(text() , 'LAKES & 
MOUNTAINS')]")
WebElement LandM;

public WebElement LandMHeader()
{
System.out.println("came inside the method");
//LandM.isDisplayed();
return LandM;
}

}

public abstract class BaseTest {

    ExcelLib eLib;
    WebDriverCommonLib wLib;
    WebDriver driver;
    HomePage homepage;

  @BeforeClass
  public void baseBeforeClass() 
  {
    eLib = new ExcelLib();
    wLib = new WebDriverCommonLib();
    driver=Driver.getBrowser();
    driver.manage().window().maximize();
    System.out.println("Browser is launched");
  }

  @BeforeMethod
  public void launchURL()
  {  
      wLib.homePage();
      //loginPage.loginToAPP();
      System.out.println("Navigated to the URL");
  }      
}

public class LakesAndMountainsHomePageTest extends BaseTest{

LakesAndMountainsHomePage lm = new LakesAndMountainsHomePage(this.driver);

 //TC TC131409 [New Lakes & Mountains Tab] : Verify New Lakes & Mountains 
Tab is displayed in header. 
 @Test(priority=0)
  public void lakesAndMountainsHeader()
  {
boolean a= lm.LandMHeader().isDisplayed(); //getting exception here
if(a==true)
{
System.out.println("Lakes And Mountains tab is present in the HomePage");
}
else
{
System.out.println("Lakes And Mountains tab is not present in the 
HomePage");
}
      lm.LandMHeader().click(); 
      System.out.println("It has clicked the tab");
  }
}

测试脚本：-

import org.openqa.selenium.WebElement;
import org.openqa.selenium.support.FindBy;
import org.openqa.selenium.support.PageFactory;
import com.actitime.genericlib.WebDriverCommonLib;

public class LakesAndMountainsHomePage extends WebDriverCommonLib{

WebDriver driver;

public LakesAndMountainsHomePage(WebDriver driver)
{
this.driver = driver;
PageFactory.initElements(driver, this);
}


@FindBy(xpath= "//*[@id='the-main-menu']//*[contains(text() , 'LAKES & 
MOUNTAINS')]")
WebElement LandM;

public WebElement LandMHeader()
{
System.out.println("came inside the method");
//LandM.isDisplayed();
return LandM;
}

}

public abstract class BaseTest {

    ExcelLib eLib;
    WebDriverCommonLib wLib;
    WebDriver driver;
    HomePage homepage;

  @BeforeClass
  public void baseBeforeClass() 
  {
    eLib = new ExcelLib();
    wLib = new WebDriverCommonLib();
    driver=Driver.getBrowser();
    driver.manage().window().maximize();
    System.out.println("Browser is launched");
  }

  @BeforeMethod
  public void launchURL()
  {  
      wLib.homePage();
      //loginPage.loginToAPP();
      System.out.println("Navigated to the URL");
  }      
}

public class LakesAndMountainsHomePageTest extends BaseTest{

LakesAndMountainsHomePage lm = new LakesAndMountainsHomePage(this.driver);

 //TC TC131409 [New Lakes & Mountains Tab] : Verify New Lakes & Mountains 
Tab is displayed in header. 
 @Test(priority=0)
  public void lakesAndMountainsHeader()
  {
boolean a= lm.LandMHeader().isDisplayed(); //getting exception here
if(a==true)
{
System.out.println("Lakes And Mountains tab is present in the HomePage");
}
else
{
System.out.println("Lakes And Mountains tab is not present in the 
HomePage");
}
      lm.LandMHeader().click(); 
      System.out.println("It has clicked the tab");
  }
}

下面是异常堆栈跟踪：-

import org.openqa.selenium.WebElement;
import org.openqa.selenium.support.FindBy;
import org.openqa.selenium.support.PageFactory;
import com.actitime.genericlib.WebDriverCommonLib;

public class LakesAndMountainsHomePage extends WebDriverCommonLib{

WebDriver driver;

public LakesAndMountainsHomePage(WebDriver driver)
{
this.driver = driver;
PageFactory.initElements(driver, this);
}


@FindBy(xpath= "//*[@id='the-main-menu']//*[contains(text() , 'LAKES & 
MOUNTAINS')]")
WebElement LandM;

public WebElement LandMHeader()
{
System.out.println("came inside the method");
//LandM.isDisplayed();
return LandM;
}

}

public abstract class BaseTest {

    ExcelLib eLib;
    WebDriverCommonLib wLib;
    WebDriver driver;
    HomePage homepage;

  @BeforeClass
  public void baseBeforeClass() 
  {
    eLib = new ExcelLib();
    wLib = new WebDriverCommonLib();
    driver=Driver.getBrowser();
    driver.manage().window().maximize();
    System.out.println("Browser is launched");
  }

  @BeforeMethod
  public void launchURL()
  {  
      wLib.homePage();
      //loginPage.loginToAPP();
      System.out.println("Navigated to the URL");
  }      
}

public class LakesAndMountainsHomePageTest extends BaseTest{

LakesAndMountainsHomePage lm = new LakesAndMountainsHomePage(this.driver);

 //TC TC131409 [New Lakes & Mountains Tab] : Verify New Lakes & Mountains 
Tab is displayed in header. 
 @Test(priority=0)
  public void lakesAndMountainsHeader()
  {
boolean a= lm.LandMHeader().isDisplayed(); //getting exception here
if(a==true)
{
System.out.println("Lakes And Mountains tab is present in the HomePage");
}
else
{
System.out.println("Lakes And Mountains tab is not present in the 
HomePage");
}
      lm.LandMHeader().click(); 
      System.out.println("It has clicked the tab");
  }
}

以下是异常堆栈跟踪：-

java.lang.NullPointerException 位于org.openqa.selenium.support.pagefactory.DefaultElementLocator.findElement（DefaultElementLocator.java:69） 位于org.openqa.selenium.support.pagefactory.internal.LocatingElementHandler.invoke（LocatingElementHandler.java:38） 在com.sun.proxy.$Proxy9.isDisplayed上显示（未知源） 位于com.acttime.usertest.lakesandsmountainshomepagetest.lakesandsmountainsheader（lakesandsmountainshomepagetest.java:27） 在sun.reflect.NativeMethodAccessorImpl.invoke0（本机方法）处 位于sun.reflect.NativeMethodAccessorImpl.invoke（未知源） 在sun.reflect.DelegatingMethodAccessorImpl.invoke处（未知源） 位于java.lang.reflect.Method.invoke（未知源） 位于org.testng.internal.MethodInvocationHelper.invokeMethod（MethodInvocationHelper.java:108） 位于org.testng.internal.Invoker.invokeMethod（Invoker.java:669） 位于org.testng.internal.Invoker.invokeTestMethod（Invoker.java:877） 位于org.testng.internal.Invoker.invokeTestMethods（Invoker.java:1201） 位于org.testng.internal.TestMethodWorker.invokeTestMethods（TestMethodWorker.java:125） 位于org.testng.internal.TestMethodWorker.run（TestMethodWorker.java:109） 位于org.testng.TestRunner.privateRun（TestRunner.java:776） 位于org.testng.TestRunner.run（TestRunner.java:634） 位于org.testng.SuiteRunner.runTest（SuiteRunner.java:425） 在org.testng.SuiteRunner.runsequential上（SuiteRunner.java:420） 位于org.testng.SuiteRunner.privateRun（SuiteRunner.java:385） 运行（SuiteRunner.java:334） 位于org.testng.SuiteRunnerWorker.runSuite（SuiteRunnerWorker.java:52） 位于org.testng.SuiteRunnerWorker.run（SuiteRunnerWorker.java:86） 在org.testng.testng.runSuitesSequentially上（testng.java:1318） 位于org.testng.testng.runSuitesLocally（testng.java:1243） 位于org.testng.testng.runSuites（testng.java:1161） 位于org.testng.testng.run（testng.java:1129） 位于org.testng.remote.AbstractRemoteTestNG.run（AbstractRemoteTestNG.java:114） 位于org.testng.remote.RemoteTestNG.initAndRun（RemoteTestNG.java:251） 位于org.testng.remote.RemoteTestNG.main（RemoteTestNG.java:77）

---

在执行下面的testng测试脚本之后，我得到了NullPointerException。当URL进入测试脚本方法时，启动URL后，它将抛出异常。你能帮我一下吗。

这个实例化是非法的

LakesAndMountainsHomePage lm = new LakesAndMountainsHomePage(this.driver);

这是空指针异常的根本原因

---

将此语句移动到BaseTest类中，创建一个类字段并在@BeforeClass方法中实例化。另外，删除此操作符

我无法看到指定驱动程序类型（firefox、chrome、IE）的驱动程序类的实现被初始化。

另一个查询的可能副本有不同的问题，因为在我的代码中，我可以在浏览器中启动URL，但当我使用page factory从对象存储库执行某些操作时，我得到了NullPointerException。附加异常stacktrace@shashanksinha是一个很好的做法！非常感谢@Manmohan_singh。代码正在执行。如果我保留lakesandsmountainshomepage lm=new lakesandsmountainshomepage（this.driver），您能解释一下问题是什么吗；我的测试脚本类中的语句？测试脚本类继承了BastTest中带TestNG注释的方法，因为没有定义构造函数，所以JVM永远不会获取LakesAndMountainsHomePage的实例化。要将其引入执行流，必须将实例化移动到@BeforeClass方法中。或者，您也可以使用在不同的驱动程序java类中初始化的类构造函数。