SpringMvc dynamic form List submission

//================User=======================

public class User implements Serializable{
    private String name;
    private int age;
    ....
}

//============== userDTO==================
public class UserDTO implements Serializable{
    private List<User> users;
    ...
}
//============== controller==================
@RequestMapping(value = "/test", method = RequestMethod.POST)
    public String test(@ModelAttribute UserDTO userDTO) {
        System.out.println(JSON.toJSONString(userDTO));
        return JSON.toJSONString(userDTO);
    }

test