如何在Selenium中重新初始化/覆盖Firefox下载首选项

Question

这是我写的代码：

    public static void main(String args[]){

            FirefoxProfile ffProfile = new FirefoxProfile();
            FirefoxBinary ffBinary = new FirefoxBinary();
            ffBinary.setTimeout(TimeUnit.SECONDS.toMillis(60));
            ffProfile.setPreference("browser.download.dir","C:\\ComonFiles");
            ffProfile.setPreference("browser.download.folderList", 2);
            ffProfile.setPreference("browser.helperApps.neverAsk.saveToDisk","application/vnd.openxmlformats-officedocument.spreadsheetml.sheet;" 
                                    + "application/pdf;"
                                    + "application/xml;"
                                    + "text/xml;"
                                    + "application/zip;"
                                    + "application/vnd.openxmlformats-officedocument.wordprocessingml.document;" + "text/plain;"
                                    + "text/csv");
System.setProperty("webdriver.gecko.driver","D:\\geckodriver.exe");
WebDriver driver = new FirefoxDriver(ffBinary, ffProfile);


//Some other operations

downloadFile1();
downloadFile2();


    }

public static void downloadFile1()
{

//Click on download button

} 

public static void downloadFile2()
{
           ffProfile.setPreference("browser.download.dir","C:\\WorkingFiles"); 
           //Click on download button

}

我想将 File2 下载到名为C:\\WorkingFiles的单独文件夹中，但即使我在downloadFile2()中再次调用设置首选项，它也不会覆盖下载设置。它总是将所有文件下载到C:\\ComonFiles。它仍然使用主要功能的首选项进行下载。