Java 如何检查使用@SessionAttributes创建的会话是否存在（Spring MVC）

请看下面的代码：

@Controller
@RequestMapping
@SessionAttributes("address")
public class HomeController {

    @RequestMapping("/home")
    public String welcome(Model model) {        
            Address address = new Address();            
            model.addAttribute("address", address);         
            return "welcome";           
    }   

}

每次我到达url“/home”时，就会调用欢迎（）方法，创建一个新对象地址，将其添加到模型中，并将其保存在名为地址的会话中

@RequestMapping
public String welcome(Model model, HttpServletRequest httpServletRequest) {
   Address vecchioAddress = (Address)httpServletRequest.getSession().getAttribute("address");
   if(vecchioAddress == null) {
            Address address = new Address();                
            model.addAttribute("address", address);
   }    

检查会话“地址”是否已经存在以避免执行这行代码的最佳方法是什么

  Address address = new Address();          
  model.addAttribute("address", address);

我使用这种方法，但我认为有一种更好、更具体的方法可以使用Spring特性来实现

@RequestMapping
public String welcome(Model model, HttpServletRequest httpServletRequest) {
   Address vecchioAddress = (Address)httpServletRequest.getSession().getAttribute("address");
   if(vecchioAddress == null) {
            Address address = new Address();                
            model.addAttribute("address", address);
   }    

}

谢谢

尝试使用注释从会话检索现有属性

@RequestMapping
public String welcome(@SessionAttribute("address") Address address) {
  // something....
}

---

您可以使用

@SessionAttribute

public String welcome(Model model, @SessionAttribute("address") Address addres) { 
       if(address == null){
            Address address = new Address();            
            model.addAttribute("address", address); 

        }
        return "welcome";
} 

---

如果那个会话还不存在呢？有没有办法防止该方法返回错误：HTTP状态400–错误请求？我想您应该检查一下。如果（！model.containsAttribute（“address”）{…}这个会话还不存在怎么办？有没有办法防止该方法返回错误：HTTP状态400–错误请求？