TreeSet<String> al4 = new TreeSet<String>();
al4.add("abcdeef");
// al1.addAll(al4);//错误,类型不匹配。
// al1.addAll(al2);
// al1.addAll(al3);
// System.out.println(al1.size());
Iterator<Student> it = al2.iterator();
while(it.hasNext()){
System.out.println(it.next());
}
}
}
/*
* class TreeSet<Worker>
* {
* Tree(Comparator<? super Worker> comp);
* }
*
* 什么时候用下限呢?通常对集合中的元素进行取出操作时,可以是用下限。
*
*/
class CompByName implements Comparator<Person>{
@Override
public int compare(Person o1, Person o2) {
int temp = o1.getName().compareTo(o2.getName());
return temp==0? o1.getAge()-o2.getAge():temp;
}
}
class CompByStuName implements Comparator<Student>{
@Override
public int compare(Student o1, Student o2) {
int temp = o1.getName().compareTo(o2.getName());
return temp==0? o1.getAge()-o2.getAge():temp;
}
}
class CompByWorkerName
implements Comparator<Worker>{
@Override
public int compare(Worker o1, Worker o2) {
int temp = o1.getName().compareTo(o2.getName());