import java.util.TreeSet;//TreeSet的通用方法
public class TreeSetTest {public static void main(String[] args) {TreeSet nums = new TreeSet();//看似是放入了基本类型的元素，但实际上这里有一个自动装箱的过程//在集合中实际的元素是Integernums.add(1);nums.add(5);nums.add(3);nums.add(2);nums.add(6);//输出元素System.out.println(nums);    //已完成排序//输出集合第一个元素
        System.out.println(nums.first());//输出集合的最后一个元素
        System.out.println(nums.last());//返回小于4的子集System.out.println(nums.headSet(4));//返回大于5的子集System.out.println(nums.tailSet(5));//返回大于等于3小于5的子集System.out.println(nums.subSet(3, 5));}
}

//需要放入TreeSet中，所以应该实现Comparable接口
public class Student implements Comparable{private String name;private int age;public Student(){}public Student(String name,int age){this.name = name;this.age = age;}public String getName() {return name;}public void setName(String name) {this.name = name;}public int getAge() {return age;}public void setAge(int age) {this.age = age;}//实现Comparable接口必须实现compareTo()方法
    @Overridepublic int compareTo(Object o) {// TODO Auto-generated method stubStudent stu = (Student) o;//return 0 this=stu//return>0 this>stu//return<0 this<stureturn this.age - stu.age;}//重写toString方法
    @Overridepublic String toString() {// TODO Auto-generated method stubreturn "["+this.name+"]";}
}

import java.util.TreeSet;public class CompareToTest {public static void main(String[] args) {TreeSet set = new TreeSet();Student a = new Student("A",18);Student b = new Student("B",13);Student c = new Student("C",15);Student d = new Student("D",11);//添加元素
        set.add(a);set.add(b);set.add(c);set.add(d);System.out.println(set);}
}

import java.util.Comparator;
import java.util.TreeSet;public class ComparatorTest {public static void main(String[] args) {//使用定制排序//需要使用Comparator接口//并与TreeSet建立关联TreeSet set = new TreeSet(new Comparator(){@Overridepublic int compare(Object o1, Object o2) {// TODO Auto-generated method stubStudent stu1 = (Student)o1;Student stu2 = (Student)o2;return stu1.getAge()>stu2.getAge()?-1:stu1.getAge()<stu2.getAge()?1:0;}});}
}

import java.util.EnumSet;enum Season{SPRING,SUMMER,FALL,WINTER
}
public class EnumSetTest1 {public static void main(String[] args) {//创建一个EnumSet，集合元素是Enum类Season的全部枚举值EnumSet es1 = EnumSet.allOf(Season.class);System.out.println(es1);//创建一个EnumSet空集合，指定集合元素为Season类的枚举值EnumSet es2 = EnumSet.noneOf(Season.class);System.out.println(es2);//为es2添加元素//集合中的顺序为枚举值的顺序
        es2.add(Season.FALL);es2.add(Season.SUMMER);System.out.println(es2);//以指定枚举值创建EnumSet集合EnumSet es3 = EnumSet.of(Season.FALL,Season.SUMMER);System.out.println(es3);}
}

import java.util.Collection;
import java.util.EnumSet;
import java.util.HashSet;
enum Season2{SPRING,SUMMER,FALL,WINTER
}
public class EnumSetTest2 {public static void main(String[] args) {Collection set = new HashSet();set.clear();set.add(Season2.FALL);set.add(Season2.SPRING);set.add(Season2.WINTER);System.out.println(set);//复制Collection中的所有元素来创建EnumSet集合EnumSet es = EnumSet.copyOf(set);System.out.println(es);}
}