Spring @SessionAttribute如何在同一控制器中检索会话对象 [英] Spring @SessionAttribute how to retrieve the session object in same controller

问题描述

我正在使用Spring 3.2.0 MVC.在这种情况下，我必须将一个对象存储到会话. 目前，我正在使用HttpSession的set和get属性来存储和检索值.

I am using Spring 3.2.0 MVC. In that I have to store one object to session. Currently I am using HttpSession set and get attribute to store and retrieve the value.

它仅返回String而不是Object.我想在尝试将@SessionAttribute设置为会话中的对象时使用@SessionAttribute，但是我无法检索会话对象

It returns only the String not Object. I want to use @SessionAttribute when I tried it sets the object in session but I could not retrieve the session object

 @RequestMapping(value = "/sample-login", method = RequestMethod.POST)
    public String getLoginClient(HttpServletRequest request,ModelMap modelMap) {
        String userName = request.getParameter("userName");
        String password = request.getParameter("password");
        User user = sample.createClient(userName, password);
        modelMap.addAttribute("userObject", user);
        return "user";
    }


     @RequestMapping(value = "/user-byName", method = RequestMethod.GET)
    public
    @ResponseBody
    String getUserByName(HttpServletRequest request,@ModelAttribute User user) {

        String fas= user.toString();
        return fas;
    }

这两种方法都在同一控制器中.我将如何使用它来检索对象?

Both methods are in same controller. How would I use this to retrieve the object?

推荐答案

@SessionAttributes注释在类级别用于:

1. 标记模型属性应在执行处理程序方法后持久保存到HttpSession
2. 在执行处理程序方法之前，使用HttpSession中先前保存的对象填充模型-如果确实存在

1. Mark a model attribute should be persisted to HttpSession after handler methods are executed
2. Populate your model with previously saved object from HttpSession before handler methods are executed -- if one do exists

因此，您可以将其与@ModelAttribute注释一起使用，例如以下示例:

So you can use it alongside your @ModelAttribute annotation like in this example:

@Controller
@RequestMapping("/counter")
@SessionAttributes("mycounter")
public class CounterController {

  // Checks if there's a model attribute 'mycounter', if not create a new one.
  // Since 'mycounter' is labelled as session attribute it will be persisted to
  // HttpSession
  @RequestMapping(method = GET)
  public String get(Model model) {
    if(!model.containsAttribute("mycounter")) {
      model.addAttribute("mycounter", new MyCounter(0));
    }
    return "counter";
  }

  // Obtain 'mycounter' object for this user's session and increment it
  @RequestMapping(method = POST)
  public String post(@ModelAttribute("mycounter") MyCounter myCounter) {
    myCounter.increment();
    return "redirect:/counter";
  }
}

也不要忘记常见的noobie陷阱:请确保将会话对象设置为可序列化.

Also don't forget common noobie pitfall: make sure you make your session objects Serializable.

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