如何使用SeleniumWebDriver解决java中的空指针异常

我正在SeleniumWebDriver中运行下面显示的代码。我正在创建类

SalesForceApplicationMethod（）

的

m1

对象，然后访问

.validation（）

方法。代码在方法内部（

.validation（）

），但它给出了以下错误：

错误追溯：

package com.syntel.pratice;
import java.util.Scanner;
import java.util.concurrent.TimeUnit;
import org.openqa.selenium.By;
import org.openqa.selenium.JavascriptExecutor;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.chrome.ChromeDriver;
import org.openqa.selenium.chrome.ChromeOptions;
import org.openqa.selenium.support.ui.ExpectedConditions;
import org.openqa.selenium.support.ui.WebDriverWait;

public class SalesForceApplicationMethod
{
  WebDriver driver;
  public void validation()
  {

    // App launcher clicking
    WebDriverWait wait = new WebDriverWait(driver,25);
    WebElement ele = wait.until(ExpectedConditions.elementToBeClickable(By.xpath("//span[@class='label slds-truncate slds-text-link']")));
    ele.click();

    // New button
    WebElement newBtn1 = driver.findElement(By.xpath("//div[contains(text(),'New')]"));
    JavascriptExecutor executor = (JavascriptExecutor)driver;
    executor.executeScript("arguments[0].click();", newBtn1);

    // Account name - first account
    driver.findElement(By.xpath("//input[@class='input uiInput uiInputText 
    uiInput--default uiInput--input']")).sendKeys("srieedherks");

    // Click Save
    driver.findElement(By.xpath("//button[@class='slds-button slds-button--neutral uiButton--default uiButton--brand uiButton forceActionButton']")).click();

    // Clicking new contact button
    WebDriverWait wait1 = new WebDriverWait(driver, 20); 
    WebElement newbt = driver.findElement(By.xpath("//div[contains(text(),'New 
    Contact')]"));
    JavascriptExecutor exe = (JavascriptExecutor)driver;
    exe.executeScript("arguments[0].click();", newbt);
    WebElement ele1 = driver.findElement(By.linkText("--None--"));
    ele1.sendKeys("Mr.");
    System.out.println("Selecting ");

    // Entering first name
    driver.findElement(By.xpath("//input[@class='compoundBorderBottom form-
    element__row input']")).sendKeys("srieedher");

    // Entering last name
    driver.findElement(By.xpath("//input[@class='compoundBLRadius 
    compoundBRRadius form-element__row input']")).sendKeys("santhakumar");

    // Click Save
    driver.findElement(By.xpath("//button[@class='slds-button slds-button--
    brand cuf-publisherShareButton undefined uiButton']")).click();

    // Logout view profile
    driver.findElement(By.xpath("//img[@src='https://c.ap5.content.force.com/pro
    filephoto/005/T/1']")).click();
    JavascriptExecutor jse = (JavascriptExecutor)driver;
    jse.executeScript("arguments[0].click();", newbt);

    // Click log out   
    driver.findElement(By.xpath("//a[contains(@class, 'profile-link-label 
    logout uiOutputURL')]")).click();
  }

  public static void main(String[] args) 
  {
    // TODO Auto-generated method stub
    System.setProperty("webdriver.chrome.driver", "D:\\chromedriver.exe");
    ChromeOptions o = new ChromeOptions();
    o.addArguments("disable-extensions");
    o.addArguments("--start-maximized");

    WebDriver driver = new ChromeDriver(o);
    driver.manage().timeouts().implicitlyWait(20, TimeUnit.SECONDS);
    driver.get("https://login.salesforce.com/");
    driver.findElement(By.id("username")).sendKeys("srieedher@force.com");
    driver.findElement(By.id("password")).sendKeys("Sriee678$");
    driver.findElement(By.id("Login")).click();

    Scanner s = new Scanner(System.in);
    System.out.println("Enter your otp:");
    String i = s.next().toString();
    System.out.println("the OTP is : "+i);
    driver.findElement(By.id("smc")).sendKeys(i);
    driver.findElement(By.id("save")).click();
    driver.findElement(By.xpath("//div[@class='slds-icon-Waffle']")).click();

    SalesForceApplicationMethod m1 = new  SalesForceApplicationMethod();
    m1.validation();
  }
}

线程“main”java.lang.NullPointerException中的异常位于com.google.common.base.Premissions.checkNotNull（预编辑‌​org.openqa.selenium.support.ui.FluentWait.（FluentWait。‌​java:102），位于org.openqa.selenium.support.ui.WebDriverWait.（WebDrive‌​java:71），位于org.openqa.selenium.support.ui.WebDriverWait.（WebDrive‌​java:45），位于com.syntel.pratice.SalesForceApplicationMethod.validation（Sa‌​lesForceApplicationM‌​java:27），位于com.syntel.pratice.SalesForceApplicationMethod.main（SalesFor‌​应用方法。‌​爪哇：88）

我的代码：

package com.syntel.pratice;
import java.util.Scanner;
import java.util.concurrent.TimeUnit;
import org.openqa.selenium.By;
import org.openqa.selenium.JavascriptExecutor;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.chrome.ChromeDriver;
import org.openqa.selenium.chrome.ChromeOptions;
import org.openqa.selenium.support.ui.ExpectedConditions;
import org.openqa.selenium.support.ui.WebDriverWait;

public class SalesForceApplicationMethod
{
  WebDriver driver;
  public void validation()
  {

    // App launcher clicking
    WebDriverWait wait = new WebDriverWait(driver,25);
    WebElement ele = wait.until(ExpectedConditions.elementToBeClickable(By.xpath("//span[@class='label slds-truncate slds-text-link']")));
    ele.click();

    // New button
    WebElement newBtn1 = driver.findElement(By.xpath("//div[contains(text(),'New')]"));
    JavascriptExecutor executor = (JavascriptExecutor)driver;
    executor.executeScript("arguments[0].click();", newBtn1);

    // Account name - first account
    driver.findElement(By.xpath("//input[@class='input uiInput uiInputText 
    uiInput--default uiInput--input']")).sendKeys("srieedherks");

    // Click Save
    driver.findElement(By.xpath("//button[@class='slds-button slds-button--neutral uiButton--default uiButton--brand uiButton forceActionButton']")).click();

    // Clicking new contact button
    WebDriverWait wait1 = new WebDriverWait(driver, 20); 
    WebElement newbt = driver.findElement(By.xpath("//div[contains(text(),'New 
    Contact')]"));
    JavascriptExecutor exe = (JavascriptExecutor)driver;
    exe.executeScript("arguments[0].click();", newbt);
    WebElement ele1 = driver.findElement(By.linkText("--None--"));
    ele1.sendKeys("Mr.");
    System.out.println("Selecting ");

    // Entering first name
    driver.findElement(By.xpath("//input[@class='compoundBorderBottom form-
    element__row input']")).sendKeys("srieedher");

    // Entering last name
    driver.findElement(By.xpath("//input[@class='compoundBLRadius 
    compoundBRRadius form-element__row input']")).sendKeys("santhakumar");

    // Click Save
    driver.findElement(By.xpath("//button[@class='slds-button slds-button--
    brand cuf-publisherShareButton undefined uiButton']")).click();

    // Logout view profile
    driver.findElement(By.xpath("//img[@src='https://c.ap5.content.force.com/pro
    filephoto/005/T/1']")).click();
    JavascriptExecutor jse = (JavascriptExecutor)driver;
    jse.executeScript("arguments[0].click();", newbt);

    // Click log out   
    driver.findElement(By.xpath("//a[contains(@class, 'profile-link-label 
    logout uiOutputURL')]")).click();
  }

  public static void main(String[] args) 
  {
    // TODO Auto-generated method stub
    System.setProperty("webdriver.chrome.driver", "D:\\chromedriver.exe");
    ChromeOptions o = new ChromeOptions();
    o.addArguments("disable-extensions");
    o.addArguments("--start-maximized");

    WebDriver driver = new ChromeDriver(o);
    driver.manage().timeouts().implicitlyWait(20, TimeUnit.SECONDS);
    driver.get("https://login.salesforce.com/");
    driver.findElement(By.id("username")).sendKeys("srieedher@force.com");
    driver.findElement(By.id("password")).sendKeys("Sriee678$");
    driver.findElement(By.id("Login")).click();

    Scanner s = new Scanner(System.in);
    System.out.println("Enter your otp:");
    String i = s.next().toString();
    System.out.println("the OTP is : "+i);
    driver.findElement(By.id("smc")).sendKeys(i);
    driver.findElement(By.id("save")).click();
    driver.findElement(By.xpath("//div[@class='slds-icon-Waffle']")).click();

    SalesForceApplicationMethod m1 = new  SalesForceApplicationMethod();
    m1.validation();
  }
}

---

因为

SalesForceApplicationMethod

类中的驱动程序未初始化。在该类中添加以下构造函数

public SalesForceApplicationMethod(WebDriver ldriver)
{
    this.driver=ldriver;
}

在主类中创建此类实例时，传递

WebDriver

SalesForceApplicationMethod m1 = new  SalesForceApplicationMethod(driver);

---

希望这对你有帮助。谢谢。

您已经创建了一个全局变量 网络驱动程序； 然后在您编写的函数main（）中

WebDriver driver = new ChromeDriver(o);

它将是main（）函数块的局部变量。可以做的一件简单的事情是初始化全局变量，而不是创建一个同名的新局部变量。为此，只需将main（）块中的上述代码行替换为

   driver = new ChromeDriver(o);

---

这将初始化在类开头声明的全局变量。

您能添加完整的错误消息吗？就像@Asew指出的，没有完整的错误跟踪，调试您的问题非常困难<代码>代码进入方法内部（哪个方法？

），但它在方法的第一行给出了错误作为空指针异常

（哪个是第一行？）没有给我们任何信息@sriedhersanthakumar您没有为

m1

instance@Asew，错误是位于org.openqa.selenium.support.ui.FluentWait.（FluentWait.java:102）的com.google.common.base.premissions.checkNotNull（premissions.java:212）上的线程“main”java.lang.NullPointerException中的异常在org.openqa.selenium.support.ui.WebDriverWait.（WebDriverWait.java:71）在org.openqa.selenium.support.ui.WebDriverWait.（WebDriverWait.java:45）在com.syntel.pratice.SalesForceApplicationMethod.validation（SalesForceApplicationMethod.java:27）在com.syntel.pratice.SalesForceApplicationMethod.main（SalesForceApplicationMethod.java:88）上请帮帮我。@iamdanchhiv，在org.openqa.selenium.support.ui.FluentWait.（FluentWait.java:102）org.openqa.selenium.support.ui.WebDriverWait.（WebDriverWait.java:71）的com.google.common.base.premissions.checkNotNull（premissions.java:212）上的线程“main”java.lang.NullPointerException中的错误是异常org.openqa.selenium.support.ui.WebDriverWait.（WebDriverWait.java:45）com.syntel.pratice.SalesForceApplicationMethod.validation（SalesForceApplicationMethod.java:27）com.syntel.pratice.SalesForceApplicationMethod.main（SalesForceApplicationMethod.java:88）非常感谢。代码运行良好。我想要退出的代码。由于实际问题已经解决，您可以将其作为单独的问题发布吗？我将作为单独的问题发布。问题只需在90分钟内提出。我会在90分钟后提问。