我的代码中为NullPointerException怎么处理

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您会看到一个NullPointerException原因，因为main()您从一开始就尝试访问该loginApplication()方法，这需要in的活动实例，WebDriver即drivertofindElement(By.name('username'));＆findElement(By.name('password'));andperform sendKeys()方法HTML DOM。

解决方案是先访问该launchApplication()方法，以便您拥有driverand 的活动实例IEbrowser。接下来，您可以访问loginApplication()方法。

这是您的工作代码块：

package demo;import org.openqa.selenium.By;import org.openqa.selenium.WebDriver;import org.openqa.selenium.ie.InternetExplorerDriver;public class Q45474353_NPE { public WebDriver driver; public void launchApplication() {System.setProperty('webdriver.ie.driver', 'C:UtilitybrowserDriversIEDriverServer.exe');driver = new InternetExplorerDriver();driver.get('https://www.gcrit.com/build3/admin/'); } public void loginApplication(String Username, String Password) {driver.findElement(By.name('username')).sendKeys(Username);driver.findElement(By.name('password')).sendKeys(Password);driver.findElement(By.id('tbd1')).click(); } public void closebrowser() {driver.close(); } public static void main(String[] args) {Q45474353_NPE obj = new Q45474353_NPE();obj.launchApplication();obj.loginApplication('admin', 'admin@123');obj.closebrowser(); }}解决方法

我已经使用Selenium用Java编写了代码。当我运行代码时，它将引发NullPointerException。检查以下异常

Exception in thread 'main' java.lang.NullPointerException at AdminInterface.loginApplication(AdminInterface.java:17) at AdminInterface.main(AdminInterface.java:29)

我的代码如下：

import org.openqa.selenium.By;import org.openqa.selenium.WebDriver;import org.openqa.selenium.ie.InternetExplorerDriver;public class AdminInterface { public WebDriver driver; public void launchApplication() throws Exception {System.setProperty('webdriver.ie.driver','C:UsersrpremDownloadsIEDriverServer_x64_3.4.0IEDriverServer.exe');driver = new InternetExplorerDriver();driver.get('https://www.gcrit.com/build3/admin/'); } public void loginApplication(String Username,String Password) {driver.findElement(By.name('username')).sendKeys(Username);driver.findElement(By.name('password')).sendKeys(Password);driver.findElement(By.id('tbd1')).click(); } public void closeBrowser() {driver.close(); } public static void main(String[] args) {AdminInterface obj = new AdminInterface();obj.loginApplication('admin','admin@123'); } }