java - 如何从不同的类中获取准确的对象？

Question

我创建一个对象:

public class Info {
    private ArrayList<Object> list;

    public Info(){
        this.list = new ArrayList<>();
    }
    public Info getInfo(){
        return this;
    }
    public void put(final byte[] macAddress, final String name) {
        HashMap<byte[], String> map = new HashMap<>();
        map.put(macAddress,name);

       list.add(map);
    }
    public ArrayList getList(){
        return list;
    }

}

我在类里面有了新信息

Info info = new Info();
info.put(mAddress1,mName1);
info.put(mAddress2,mName2);

但我想从另一个类获取这个对象。我怎样才能得到这个对象？(我只创建/新建一次)

Answer 1

<强>1。使Info类成为单例

    public class Info {
      public static Info info;
      private ArrayList<Object> list;

      public static Info getInstance(){
        if(info == null)
           info = new Info();
        return info;
      }    

      private Info(){
        this.list = new ArrayList<>();
      }

      public void put(final byte[] macAddress, final String name) {
        HashMap<byte[], String> map = new HashMap<>();
        map.put(macAddress,name);

        list.add(map);
      }

      public ArrayList getList(){
        return list;
      }
    }

<强>2。用法

Info info = Info.getInstance();
info.put(mAddress1,mName1);
info.put(mAddress2,mName2);