我的任务是打印朋友的朋友，这不是我的朋友

Question

public void notMyFriend(Student student1) {
        System.out.println("Friends who are not my friends:");
        int i;
        for (i = 0; i < student1.friendList.size();i++) {
            for (int j = 0; j < friendList.size(); j++) {
                if (student1.friendList.get(i) == friendList.get(j)) continue;
                else {
                    System.out.println(student1.friendList.get(i).getName());
                }
            }

        }
    }

那个代码片段确实打印了我的朋友和我朋友的朋友，这些朋友和朋友不是互相帮助的。我不明白为什么？有人可以帮助我吗？

学生：

public class Student { 
    private int Number; 
    private String Name; 
    private String Gender; 
    private List<Student> friendList = new ArrayList<Student>();
    }

Answer 1

如果您的学生班级具有equals()的合适实施，您可以使用removeAll()

hisFriends.removeAll(yourFriends);
System.out.println(hisFriends); // not your friends

Answer 2

在不使用设定操作的情况下打印不相互的朋友：

 public void notMyFriend(Student student1) {
    System.out.println("Friends who are not my friends:");
    int i;
    for (i = 0; i < student1.friendList.size();i++) {
        for (int j = 0; j < friendList.size(); j++) 
            if (student1.friendList.get(i) == friendList.get(j)) break;

            if(j==friendList.size())
             System.out.println(student1.friendList.get(i).getName());

         }
}