如何在appium中使用字符串参数启动activity？

import io.appium.java_client.AppiumDriver;
import io.appium.java_client.android.AndroidDriver;
import io.appium.java_client.remote.MobileCapabilityType;
import org.openqa.selenium.remote.DesiredCapabilities;

public class AppiumExample {
    public static void main(String[] args) {
        // 设置DesiredCapabilities对象
        DesiredCapabilities capabilities = new DesiredCapabilities();
        capabilities.setCapability(MobileCapabilityType.PLATFORM_NAME, "Android");
        capabilities.setCapability(MobileCapabilityType.DEVICE_NAME, "deviceName");
        
        // 设置appPackage和appActivity参数
        String appPackage = "com.example.app";
        String appActivity = "com.example.app.MainActivity";
        capabilities.setCapability("appPackage", appPackage);
        capabilities.setCapability("appActivity", appActivity);
        
        // 创建AppiumDriver对象
        AppiumDriver driver = new AndroidDriver(new URL("http://127.0.0.1:4723/wd/hub"), capabilities);
        
        // 使用startActivity方法启动应用程序
        driver.startActivity(appPackage, appActivity);
        
        // 进行其他测试操作
        // ...
        
        // 关闭driver
        driver.quit();
    }
}