我们如何在GWT应用程序中从服务器端处理Map对象？

Question

通常我们会在客户端（GWT应用程序）中将列表或设置对象作为 JsArray 处理。有没有这样的方法来处理Map对象？

例如：

早些时候我的服务器端DTO是

public class CustomDTO {

    private Users users;

    public CustomDTO(Users users) {
        this.users = users;
    }

    public Users getUsers() {
        return users;
    }

    public void setUsers(Users users) {
        this.users = users;
    }
}    

所以在GWT应用程序中，我有以下代码来获取它

public final class CustomDTO extends JavaScriptObject {
    protected CustomDTO() {
    }
    public native JsArray<UsersOverlay> getUsers() /*-{return this.users;}-*/;
    }

但现在我的服务器端DTO如下

public class CustomDTO {

    private Users users;

    private Map<Employee, List<Taskss>> tasksMap = Maps.newHashMap();

    public CustomDTO(Users users, Map<Employee, List<Taskss>> tasks) {
        this.users = users;
        this.tasks = tasks;
    }

    public Users getUsers() {
        return users;
    }

    public void setUsers(Users users) {
        this.users = users;
    }

    public List<Tasks> getTasks() {
        return tasks;
    }

    public void setTasks(List<Tasks> tasks) {
        this.tasks = tasks;
    }
}

所以我现在在客户端有以下代码，

public final class CustomDTO extends JavaScriptObject {
    protected CustomDTO() {
    }
    public native JsArray<UsersOverlay> getUsers() /*-{return this.users;}-*/;
    public native Map<Employees, JsArray<Tasks>> getTasks() /*-{return this.tasks;}-*/;
}

这是正确的还是有其他方法来处理Map对象？因为如果我这样处理我会得到ClassCastException吗？如果我这样做：

final List<Map<Employees, JsArray<Tasks>> list = new ArrayList(); 
for (int i = 0; i < List<CustomDTO>.length(); i++) { // where List<CustomDTO> is the response from the server 
  list.add(List<CustomDTO>.get(i).getTasks()); 
} 
//**Upto this line it works. I got the ClassCastException in the following line** 
for (Map<Employees, JsArray<Tasks>> map : list) { 
}

请参考以下图片：