问如何在Selenium Chrome功能中设置默认下载目录？

private static DesiredCapabilities getChromeCapabilities() throws Exception {

    String chromePath = BrowserUtil.class.getResource("/Browserdrivers/chromedriver.exe").getPath();
    System.setProperty("webdriver.chrome.driver", chromePath);
    String downloadFilepath = "C:\\TestDownloads";
    ChromeOptions options = new ChromeOptions();
    HashMap<String, Object> chromePrefs = new HashMap<String, Object>();
    chromePrefs.put("profile.default_content_settings.popups", 0);
    chromePrefs.put("download.default_directory", downloadFilepath);
    options.setExperimentalOption("prefs", chromePrefs);
    options.addArguments("--test-type");
    options.addArguments("start-maximized", "disable-popup-blocking");

    DesiredCapabilities chromeCapabilities = DesiredCapabilities.chrome();
    setProxy(chromeCapabilities);
    chromeCapabilities.setPlatform(Platform.WINDOWS);
    chromeCapabilities.setCapability("name", MDC.get("testname"));
    chromeCapabilities.setCapability(ChromeOptions.CAPABILITY, options);
    return chromeCapabilities;
}