无法在要素文件中运行多个方案

基类：

package env;

import java.util.concurrent.TimeUnit;

import org.openqa.selenium.WebDriver;
import org.openqa.selenium.chrome.ChromeDriver;
import org.openqa.selenium.firefox.FirefoxDriver;
import org.openqa.selenium.firefox.FirefoxProfile;
import org.openqa.selenium.firefox.internal.ProfilesIni;
import org.openqa.selenium.ie.InternetExplorerDriver;
import org.openqa.selenium.safari.SafariDriver;
import cucumber.api.Scenario;
import managers.FileReaderManager;

public class Env 
{
    static WebDriver driver = null;
    Scenario s;


    static String browserName = null;

    public static String getBrowserName()
    {
        browserName = System.getProperty("browser"); 

        if(browserName == null)
            browserName = "ch";
        return browserName;
    }

    public static WebDriver CreateWebDriver(String browser)
    {
        System.out.println("Browser: " + browser);

        switch (browser.toLowerCase()) {
            case "ff":
            case "firefox":
                System.out.println("Firefox is selected");
                System.setProperty("webdriver.gecko.driver", 
                                   "E:\\eclipse\\geckodriver.exe");
                driver=new FirefoxDriver();
                break;

            case "ch":
            case "chrome":
                System.out.println("Google chrome is selected");
                System.setProperty("webdriver.chrome.driver", 
                FileReaderManager.getInstance().getConfigReader().getDriverPath());
                driver = new ChromeDriver();
                break;

            case "ie" :
            case "internetexplorer":
                System.out.println("Internet Explorer is selected");
                driver = new InternetExplorerDriver();
                break;

            case "safari":
                System.out.println("Safari is selected");
                driver = new SafariDriver();
                break;

             default:
                 System.out.println("Invalid browser name "+browser);
                 System.exit(0);
                    break;  
        }//switch

        driver.manage().deleteAllCookies();
        driver.manage().window().maximize();
        driver.manage().timeouts().pageLoadTimeout(60, TimeUnit.SECONDS);
        driver.manage().timeouts().setScriptTimeout(60, TimeUnit.SECONDS);
        driver.manage().timeouts().implicitlyWait(20, TimeUnit.SECONDS);

        return driver;
    }

    public static WebDriver getDriver() {
        return driver;
    }

    public static void setDriver(WebDriver driver) {
        Env.driver = driver;
    }

}

钩类：

import org.openqa.selenium.OutputType;
import org.openqa.selenium.TakesScreenshot;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebDriverException;
import org.openqa.selenium.chrome.ChromeDriver;

import cucumber.api.Scenario;

public class Hooks extends Env
{

    //public static WebDriver driver;
    Logger log = Logger.getLogger(Hooks.class);
    Scenario scenario = null;

    @Before
    public void before(Scenario scenario) {
        this.scenario = scenario;

        Env.CreateWebDriver(getBrowserName());

    }

    @After
    /**
     * Embed a screenshot in test report if test is marked as failed
     */
    public void afterMethodt(Scenario scenario) {

        getDriver().quit();

    }
}

当我运行跑步者类时，我得到了这个错误 .

[31morg.openqa.selenium.remote.SessionNotFoundException：会话ID为空 . 调用quit（）后使用WebDriver？构建信息：版本：'2.45.0'，修订版：'5017cb8e7ca8e37638dc3091b2440b90a1d8686f'，时间：'2015-02-27 09:10:26'系统信息：主机：'DESKTOP-235EN1N'，ip：'192.168.0.105'， os.name：'Windows 10'，os.arch：'amd64'，os.version：'10 .0'，java.version：'1.8.0_131'驱动程序信息：driver.version：RemoteWebDriver