public class TestTreeSet
{
public static void main(String[] args)
{
java.util.TreeSet treeSet = new java.util.TreeSet();
treeSet.add("3");
treeSet.add("1");
treeSet.add("5");
System.out.println(treeSet);
java.util.ArrayList arrayList = new java.util.ArrayList(treeSet);
System.out.println(arrayList);
}
}
{
public static void main(String[] args)
{
java.util.TreeSet treeSet = new java.util.TreeSet();
treeSet.add("3");
treeSet.add("1");
treeSet.add("5");
System.out.println(treeSet);
java.util.ArrayList arrayList = new java.util.ArrayList(treeSet);
System.out.println(arrayList);
}
}
2.由TreeSet到ArrayList很简单。只要在构造方法内传入TreeSet对象即可。因为他们都通过Collection接口来操作。
[1, 3, 5]
[1, 3, 5]
请问TreeSet中的元素改变后不能重新排序呀?
怎么办呢?
您好!
我现在需要从大到小排列该怎么做呢?
谢谢!
{
class MyComparator implements java.util.Comparator
{
public int compare(Object o1,Object o2)
{
Integer i1 = (Integer)o1;
Integer i2 = (Integer)o2;
return - i1.compareTo(i2);
}
public boolean equals(Object obj)
{
return true;
}
}
public static void main(String[] args)
{
java.util.TreeSet treeSet = new java.util.TreeSet(new TestTreeSet().new MyComparator());
treeSet.add(new Integer(3));
treeSet.add(new Integer(1));
treeSet.add(new Integer(5));
System.out.println(treeSet);
java.util.ArrayList arrayList = new java.util.ArrayList(treeSet);
System.out.println(arrayList);
}
}