详谈fastjson将对象格式化成json时的两个问题

class Base{
    private int id;

 public Long getId() {

 return id;
 }

 public void setId(Long id) {
 this.id = id;
 }
}

class User extends Base{
    private String name;

 public String getName() {
 return name;
 }

 public void setName(String name) {
 this.name = name;
 }
}

class UserVO{
    public User user;
}

class UserVO{
    public ArrayList<User> list;
}