Question

我有以下内容：

one or zero to many

第二部分是打印集合中的所有文档。但是，每次重新运行程序时，集合都不会清除。有谁知道为什么？

Answer 1

而不是这样做

  @Controller
 public class LoginController {
  @RequestMapping(value = "/login", method = RequestMethod.GET)
  public ModelAndView showLogin(HttpServletRequest request,     HttpServletResponse response) {
    ModelAndView mav = new ModelAndView("login");
    mav.addObject("login", new LoginBean());
    return mav;
  }

  @RequestMapping(value = "/loginProcess", method = RequestMethod.POST)
  public ModelAndView loginProcess(HttpServletRequest request, HttpServletResponse response,
  @ModelAttribute("login") LoginBean login) {
    ModelAndView mav = null;
    try {
        /*
         * Will add the logic for validate User later 
         */
        //User user = userService.validateUser(login);
        if (null != login) {
            mav = new ModelAndView("welcome");
            mav.addObject("<i>Happy to see you </i>",login.getXid());
            } else {
            mav = new ModelAndView("login");
            mav.addObject("message", "Please check.. Xid or Password may be wrong !!!");
            }
    }
    catch(Exception ex){
        ex.printStackTrace();
    }
    return mav;
  }

这样做

db.collection.remove({})

此外，您还不需要此行db.accounts.remove({})

如果需要动态集合名称，可以执行以下操作：

collection=db['accounts']

Answer 2

而不是

db.collection.remove({})

你可以试试这个

collection.delete_many({})

希望能解决你的问题。

Answer 3

只需这样做

db.accounts.drop()

从Pymongo的馆藏中删除文件？

3 个答案: