Selenium WebDriver java.lang.NullPointerException

我过去曾使用过这种方法，但最近我对selenium做得不多。我正在尝试设置此测试，以使多个案例按顺序运行

这是我的密码

import org.junit.*;
import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.firefox.FirefoxDriver;
import org.openqa.selenium.interactions.Actions;
import org.openqa.selenium.support.ui.Select;
import java.time.Duration;

public class TotalAutomatation {

static WebDriver driver;

@BeforeClass public static void setup() throws InterruptedException {
    System.setProperty("webdriver.gecko.driver", "C:\\Users\\con15096\\snow_demo\\autotile\\drivers\\geckodriver.exe");
    WebDriver driver = new FirefoxDriver();
    driver.manage().window().maximize();
    driver.get("https://nk.okta.com/login/login.htmfromURI=%2Fapp%2Fservicenow_app2%2Fexkbcm77encfzK3a80x7%2Fsso%2Fsaml%3FSAMLRequest%3DnVJdb5swFP0ryO9gMGkhVojEEk2L1nWoyfqwl8mBS2vF2MzX0Ky%252FfsTJ1O5hVbVH2%252Beej3u8QNEp1vNycI%252F6Dn4OgC44dkojP78UZLCaG4ESuRYdIHc135ZfbjiLYt5b40xtFAlKRLBOGr0yGocO7BbsKGv4dndTkEfneuSUYi%252BtdEJaJTVgA2OEZ1SozVNUm45qMfbiAaLGkGA9eZFanEhfKPQhMgcnPFj0Pb0QTPM%252FpiOjcDzs6y7LQNft8%252BdU5PExo4iGnuKQ4KOxNfiwBWmFQiDBZl2Q7e2qnWe1SK%252FZ1fwaGtam6TxncTtvr6DJ9yzJJiBWAlGO8DKKOMBGoxPaFYTFSR7GecjSXRzz2YzPkihm6XcSVJc1fZC6kfrh7Z3uzyDkn3a7Kqy%252BbneeYJQN2NsJ%252Fb%252FrvAeLfpWTCFkufL3cJ7CvG3%252FbnPhTM1m%252B28WCvta6KPf8lGWzroyS9a%252BgVMo8rSwIN%252BVzdgBfVSfcv%252B0kUeJvZBO2HsqhE1KVTWMBkdDlRffvz738DQ%253D%253D%26RelayState%3Dhttps%253A%252F%252Fspiritairlinesdev.service-now.com%252Fsolveit%253Fid%253Dsolveit_dept_dev");
    Thread.sleep(1000);
    driver.findElement(By.id("okta-signin-username")).sendKeys("username");
    Thread.sleep(1500);
    driver.findElement(By.id("okta-signin-password")).sendKeys("password");
    Thread.sleep(1000);
    driver.findElement(By.id("okta-signin-submit")).click();
    Thread.sleep(1000);
    driver.get("https://spiritairlinesdev.service-now.com/solveit");
}

@Test public  void getFirstTile1() throws InterruptedException {
    Thread.sleep(5000);
    driver.findElement(By.xpath("//*[@id=\"xd150fd31cb10020000f8d856634c9ce6\"]/li[1]/a")).click();
    Thread.sleep(6000);
    Select dropList = new Select(driver.findElement(By.id("edit_tile_level")));
    dropList.selectByVisibleText("FlightOPS/ Inflight");
    Thread.sleep(1500);
    dropList.selectByVisibleText("Submit a New Request");
    Thread.sleep(1500);
    dropList.selectByVisibleText("System Access Request");
    Thread.sleep(2000);
    WebElement TemplateCard = driver.findElement(By.xpath("//*[@id=\"template_color\"]"));
    WebElement card1= driver.findElement(By.xpath("//*[@id=\"02844eecdb486700433c38ff9d961914_color\"]"));
    new Actions(driver)
            .moveToElement(card1)
            .pause(Duration.ofSeconds(1))
            .clickAndHold(card1)
            .pause(Duration.ofSeconds(1))
            .moveToElement(TemplateCard)
            .pause(Duration.ofSeconds(1))
            .release().perform();
    Thread.sleep(2000);
    System.out.println("I have the first tile");
    driver.findElement(By.id("previous_parent")).click();
    Thread.sleep(1500);
    driver.findElement(By.id("previous_parent")).click();
    Thread.sleep(1500);
    driver.findElement(By.id("previous_parent")).click();
    Thread.sleep(1500);
    dropList.selectByVisibleText("Airport Stations");
    Thread.sleep(1500);
    dropList.selectByVisibleText("Submit a New Request");
    Thread.sleep(2000);
    dropList.selectByVisibleText("System Access Request");
    Thread.sleep(2000);
    driver.findElement(By.id("save_new_tile")).click();

}

@AfterClass public static void closeWindow() throws InterruptedException {
    Thread.sleep(1500);
    driver.close();
}

}

它运行@BeforeTest用例，但在尝试进入第一个@Test时失败

我很难理解为什么在@BeforeClass之后它会中断。

 WebDriver driver = new FirefoxDriver();

您可以创建一个局部变量方法。所以静态字段永远不会被写入

---

只需删除

WebDriver

就可以真正访问静态字段。

哪一行抛出nullreferenceexception？全局、本地、运行时、编译时、初始化、声明都写得正确-1促使我写出非常有限的答案

public class TotalAutomatation {

// This is global variable
// this variable is declared but not initialized
static WebDriver driver;

   @BeforeClass 
     // I am happy at compile time and run time as I can 
     // access local variable which is declared and initialized both
   public static void setup() throws InterruptedException {

    // this is local variable with same name
    // this variable is declared and initialized also
    // I have overridden driver value for BeforeClass
    WebDriver driver = new FirefoxDriver();

} // scope ended here for local variable

@Test 
 // I am not happy at run time as I have access to global variable
 // which is only declared but not initialized
public void getFirstTile1() throws InterruptedException {
 // here at run time global variable will be accessed which 
 // is static variable which and it is null :(
 // My next statement will suffer NullPointerException :-(
driver.findElement();
}