参考: selenium - Access to file download dialog in Firefox - Stack Overflow
参考: http://blog.codecentric.de/en/2010/07/file-downloads-with-selenium-mission-impossible/
第一步是要确认自动保存文件的类型。
要确定你想要自动下载的内容类型，你可使用 curl:
curl -I URL | grep "Content-Type"
找到内容类型的另一种方法是使用 `requests <http://python-requests.org>`模块， 你可以像这样使用:
import requests
content_type = requests.head('http://www.python.org').headers['content-type']
print(content_type)
一旦内容类型被确认，你可以用它来设置firefox配置文件的偏好: browser.helperApps.neverAsk.saveToDisk 下面是一个例子:
import os
from selenium import webdriver
fp = webdriver.FirefoxProfile()
fp.set_preference("browser.download.folderList",2)
fp.set_preference("browser.download.manager.showWhenStarting",False)
fp.set_preference("browser.download.dir", os.getcwd())
fp.set_preference("browser.helperApps.neverAsk.saveToDisk", "application/octet-stream")
browser = webdriver.Firefox(firefox_profile=fp)
browser.get("http://pypi.python.org/pypi/selenium")
browser.find_element_by_partial_link_text("selenium-2").click()
在上面的例子中，application/octet-stream 被当作内容类型。
该 browser.download.dir 选项指定了你要下载文件的目录。
FirefoxProfile profile = new FirefoxProfile();
String path = "C:\\Test\\";
profile.setPreference("browser.download.folderList", 2);
profile.setPreference("browser.download.dir", path);
profile.setPreference("browser.download.manager.alertOnEXEOpen", false);
profile.setPreference("browser.helperApps.neverAsk.saveToDisk", "application/msword, application/csv, application/ris, text/csv, image/png, application/pdf, text/html, text/plain, application/zip, application/x-zip, application/x-zip-compressed, application/download, application/octet-stream");
profile.setPreference("browser.download.manager.showWhenStarting", false);
profile.setPreference("browser.download.manager.focusWhenStarting", false);
profile.setPreference("browser.download.useDownloadDir", true);
profile.setPreference("browser.helperApps.alwaysAsk.force", false);
profile.setPreference("browser.download.manager.alertOnEXEOpen", false);
profile.setPreference("browser.download.manager.closeWhenDone", true);
profile.setPreference("browser.download.manager.showAlertOnComplete", false);
profile.setPreference("browser.download.manager.useWindow", false);
profile.setPreference("services.sync.prefs.sync.browser.download.manager.showWhenStarting", false);
profile.setPreference("pdfjs.disabled", true);
driver = new FirefoxDriver(profile);
