spring mvc use model.addAttribute（nav）无法使用$ {nav.id}获取jsp中父类的属性

Question

i am new Spring learner.

1. i'm really confused about model.addAttribute

2. how can i get all attributes(include parent)

   in below there are my code,see this code,please:

---

Controller: 
@RequestMapping("/nav/addOrEdit")
public String navAdd(Nav nav,ModelMap model){
    if(nav.getId()!=null&&nav.getId()!=0) {
        nav=siteService.getNav(nav.getId());
        model.addAttribute(nav);
        System.out.println("nav.id:"+nav.getId());
    }
    return "CJ/nav/addOrEdit";
}

Nav:
public class Nav extends PO{
    private static final long serialVersionUID = -13569672251584L;

    protected String code;
    @NotEmpty
    protected String name;

    public String getCode() { return code; }
    public void setCode(String code) { this.code = code; }
    public String getName() { return name; }
    public void setName(String name) { this.name = name; }
}

PO:
public class PO implements Serializable {

    private static final long serialVersionUID = 4572077184754045588L;
    protected Long Id;

    public Long getId() {return Id;}
    public void setId(Long id) {Id = id;}
}

jsp:
console.log("${nav}"); -->Nav{code=1, name=test},

no id，how can i get the parent class's attributes?

Answer 1

In your case you are adding your parent class object in Map . So you can not directly access that object instead of putting object directly into Map add that object with some key and directly access it on JSP. ie

model.addAttribute("nav",nav);

More details check Spring Documention of Model interface

Now you can access your value directly.