1.新建一个Callback抽象类
public interface Callback {
Map<String, Object> a() ;
}
2. b继承Callback
public class b implements Callback{
@Override
public Map<String, Object> a() {
Map<String,Object> map=new HashMap<>();
map.put("china","中国");
return map;
}
}
3.
public static void main(String[] args){
Callback callback= new b();
System.out.println(callback.a());
}
打印输出 {china=中国}
