java - 无法访问 ArrayList 内容

Question

我一直在使用 Xsrteam 将 XML 解析为 ArrayList。它有效，但由于某种原因我无法访问数组的内容。

处理 ArrayList 数据的类:

@XStreamAlias("BOARDS")
public class Boards {
    @XStreamImplicit(itemFieldName = "id")
    public ArrayList ids = new ArrayList();

    //region GETTERS-SETTERS
    public void setIds(ArrayList temp){
        this.ids = temp;
    }
    public List getIds(){
        return ids;
    }
//    endregion
}

@XStreamAlias("id")
class Id {

    @XStreamAlias("board")
    private String board;

    @XStreamAlias("description")
    private String description;

    @XStreamAlias("price")
    private String price;

    @XStreamAlias("shape")
    private String shape;

    @XStreamAlias("riding_level")
    private String ridingLevel;

    @XStreamAlias("riding_style")
    private String ridingStyle;

    @XStreamAlias("camber_profile")
    private String camber;

    @XStreamAlias("stance")
    private String stance;

    @XStreamAlias("picture")
    private String picture;

    <<public getters - setters here>>
}

我如何尝试访问这些getter:

Boards boards = (Boards) xstream.fromXML(reader); // parse xml into array list
boards.getIds().get(0).getPrice(); //!!getPrice() cannot be resolved

first 是 Object first =boards.getIds().get(0);

这是使用调试器的样子:

Answer 1

Boards 具有原始类型，因此不清楚 ArrayList ids 内应包含哪些对象类型。因此，您应该显式转换 boards.getIds().get(0) 的结果:

((Id) boards.getIds().get(0)).getPrice()

或泛化Boards类:

public class Boards<E> {

    public List<E> ids = new ArrayList<E>();

    //region GETTERS-SETTERS
    public void setIds(ArrayList<E> temp){
        this.ids = temp;
    }
    public List<E> getIds(){
        return ids;
    }
//    endregion
}

您可以阅读有关泛型的信息 here