1.迭代器:Iterator和ListIterator

package bilibili.chapter16;

import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.ListIterator;

public class Iiterator {
    public static void main(String []args){
        List<String>list = new LinkedList<>();
        list.add("yzq");
        list.add("yxc");
        list.add("yzz");
        ListIterator<String>iterator = list.listIterator();
        while(iterator.hasNext()){
            System.out.println(iterator.next());
        }

        while (iterator.hasPrevious()) {
            System.out.println(iterator.previous());
        }


    }

}

2.Collections集合类
(1)字符串逆序–使用compareTo

public class Iiterator {
    public static void main(String []args){
        List<String>list = new LinkedList<>();
        list.add("1yzq");
        list.add("2yxc");
        list.add("4yzz");


        Collections.sort(list, new Comparator<String>() {
            @Override
            public int compare(String o1, String o2) {
                return o2.compareTo(o1);
            }
        });
        System.out.println(list);
    }

}

(2)类排序

public class Iiterator {
    public static void main(String []args){
        List<String>list = new LinkedList<>();
        list.add("1yzq");
        list.add("2yxc");
        list.add("4yzz");


        Collections.sort(list, new Comparator<String>() {
            @Override
            public int compare(String o1, String o2) {
                return o2.compareTo(o1);
            }
        });
        System.out.println(list);
        List<Person>list2 = new ArrayList<>();
        list2.add(new Person(1,"yzq",22));
        list2.add(new Person(2,"yxc",25));
        list2.add(new Person(2,"abb",25));
        list2.add(new Person(3,"yzz",20));
        Collections.sort(list2, new Comparator<Person>() {
            @Override
            public int compare(Person o1, Person o2) {
                if(o1.getID()==o2.getID()){
                    return o1.getName().compareTo(o2.getName());
                }else{
                    return o1.getID()-o2.getID();
                }
            }
        });
        System.out.println(list2);
    }

}

3.斗地主案例

public class Homework {
    public static void main(String[] args) {
        ArrayList<String>colors = new ArrayList<>(Arrays.asList("♠","♥","♣","♦"));
        ArrayList<String>number = new ArrayList<>();
        ArrayList<String>pokes = new ArrayList<>();
        ArrayList<String>last = new ArrayList<>();
        ArrayList<String>person1 = new ArrayList<>();
        ArrayList<String>person2 = new ArrayList<>();
        ArrayList<String>person3 = new ArrayList<>();


        for(int i=2;i<=10;i++){
            number.add(i+" ");
        }

        number.addAll(Arrays.asList("J","Q","K","A"));


        for(String color:colors){
            for(String num:number) {
                pokes.add(color + num);

            }

        }
        //System.out.println(pokes);
        pokes.addAll(Arrays.asList("大王","小王"));
        Collections.shuffle(pokes);
        for (int i=0;i<pokes.size();i++){
            String s = pokes.get(i);
            if(i>pokes.size()-3){
                last.add(s);
            }else if(i%3==0){
                person1.add(s);
            }else if(i%3==1){
                person2.add(s);
            }else {
                person3.add(s);
            }
        }
        System.out.println("第一个人的牌：");
        System.out.println(person1);
        System.out.println("第二个人的牌：");
        System.out.println(person2);
        System.out.println("第三个人的牌：");
        System.out.println(person3);

    }
}