TA貢獻1772條經驗 獲得超5個贊
for(int i=0;i<list.size();i++){
List l = list.get(i);
for(Object o:l){
if(o instanceof User){
User?user = (User) o;
System.out.println(user);
}
if(o instanceof Department){
Department dep?= (Department) o;
System.out.println(dep);
}
}
}
TA貢獻1854條經驗 獲得超8個贊
1 public class MyTests 2 { 3 public static void main(String[] args) 4 { 5 List<List<Reportable>> reportables = new ArrayList<List<Reportable>>(); 6 7 List<Reportable> users = new ArrayList<Reportable>(); 8 users.add(new User()); 9 users.add(new User()); 10 users.add(new User()); 11 12 List<Reportable> departments = new ArrayList<Reportable>(); 13 departments.add(new Department()); 14 departments.add(new Department()); 15 departments.add(new Department()); 16 17 reportables.add(users); 18 reportables.add(departments); 19 20 for (List<Reportable> reports : reportables) 21 { 22 for (Reportable element : reports) 23 { 24 element.printMe(); 25 } 26 } 27 } 28 } 29 30 interface Reportable 31 { 32 public void printMe(); 33 } 34 35 class User implements Reportable 36 { 37 @Override 38 public void printMe() 39 { 40 System.out.println("I am a user."); 41 } 42 } 43 44 class Department implements Reportable 45 { 46 @Override 47 public void printMe() 48 { 49 System.out.println("I am a department"); 50 } 51 }
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