问题描述
@SessionAttributes在什么确切的情况下被清除？我试图在页面中使用两个模型时发现了一些混乱的行为。
Under what exact circumstances do @SessionAttributes get cleared? I've discovered some confusing behaviour when trying to use two models in a page.
当我使用此控制器执行GET后接POST时...
When I do a GET followed by a POST using this controller...
@Controller
@RequestMapping("/myPage*")
@SessionAttributes(value = {"object1", "object2"})
public class MyController {
@RequestMapping(method = RequestMethod.GET)
public String get(Model model) {
model.addAttribute("object1", new Object1());
model.addAttribute("object2", new Object2());
return "myPage";
}
@RequestMapping(method = RequestMethod.POST)
public String post(@ModelAttribute(value = "object1") Object1 object1) {
//do something with object1
return "myPage";
}
}
... object2从模型中清除。它不再作为@SessionAttribute存在，不能在我的视图页面上访问。
...object2 gets cleared from the Model. It no longer exists as a @SessionAttribute and cannot be accessed on my view page.
但是如果第二个方法的签名被修改为this ...
However if the signature of the second method is modified to this...
public String post(@ModelAttribute(value = "object1") Object1 object1,
@ModelAttribute(value = "object2") Object2 object2) {
...然后object2不会从模型中清除，
...then object2 does not get cleared from the model and is available on my view page.
@SessionAttributes的javadoc说：
The javadoc for @SessionAttributes says:
但我不
任何人都可以解释这个行为，或者是一个错误？
Can anyone explain this behaviour or is it a bug?
推荐答案
您表示通过调用
SessionStatus.setComplete
public void post(...., SessionStatus status) {
status.setComplete();
}
也就是说，我不明白为什么你应该放弃一个模型属性
That said, I don't see why you should be loosing one model attribute and not the other.
您尝试过以下操作：
@ModelAttribute("object1")
public Object object1() { return new Object(); }
@ModelAttribute("object2")
public Object object2() { return new Object(); }
看看如何比较手动将属性放在模型中。
And see how that compares to putting the attributes in the model by hand.
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