为集合详解提供的代码（自然排序、比较器排序的实例、Map集合的两种遍历、斗地主案例）

这篇博客展示了Java集合框架中TreeSet的使用，包括通过实现Comparable接口进行自然排序和使用Comparator接口进行定制排序。此外，还演示了Map集合的两种遍历方式，并提供了一个斗地主案例，说明如何使用HashMap和TreeSet实现扑克牌的洗牌和发牌逻辑。

自然排序Comparable：

比较器排序Comparator：

Map集合的遍历（方式一）：

Map集合的遍历（方式二）：

斗地主案例：

自然排序Comparable：

//学生类
public class Student implements Comparable<Student> {
    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;
    }

    @Override
    public int compareTo(Student s) {
       //按照年龄从小到大排序
       int num = this.age - s.age;
       //年龄相同时，按照姓名的字母顺序排序
       int num2 = num==0?this.name.compareTo(s.name):num;
       return num2;
    }
}

//测试类
public class TreeSetDemo0 {
    public static void main(String[] args) {
        //创建集合对象
        TreeSet<Student> ts = new TreeSet<>();

        //创建学生对象
        Student s1 = new Student("xishi", 29);
        Student s2 = new Student("wangzhaojun", 28);
        Student s3 = new Student("diaochan", 30);
        Student s4 = new Student("yangyuhuan", 33);

        Student s5 = new Student("linqingxia",33);
        Student s6 = new Student("linqingxia",33);

        //把学生添加到集合
        ts.add(s1);
        ts.add(s2);
        ts.add(s3);
        ts.add(s4);
        ts.add(s5);
        ts.add(s6);

        //遍历集合
        for (Student s : ts) {
            System.out.println(s.getName() + "," + s.getAge());
        }
    }
}

比较器排序Comparator：

//学生类
public class Student {
    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;
    }
}

//测试类
public class TreeSetDemo {
    public static void main(String[] args) {
        //创建集合对象
        TreeSet<Student> ts = new TreeSet<Student>(new Comparator<Student>() {
            @Override
            public int compare(Student s1, Student s2) {
                int num = s1.getAge() - s2.getAge();
                int num2 = num == 0 ? s1.getName().compareTo(s2.getName()) : num;
                return num2;
            }
        });

        //创建学生对象
        Student s1 = new Student("xishi", 29);
        Student s2 = new Student("wangzhaojun", 28);
        Student s3 = new Student("diaochan", 30);
        Student s4 = new Student("yangyuhuan", 33);

        Student s5 = new Student("linqingxia",33);
        Student s6 = new Student("linqingxia",33);

        //把学生添加到集合
        ts.add(s1);
        ts.add(s2);
        ts.add(s3);
        ts.add(s4);
        ts.add(s5);
        ts.add(s6);

        //遍历集合
        for (Student s : ts) {
            System.out.println(s.getName() + "," + s.getAge());
        }
    }
}

Map集合的遍历（方式一）：

public class MapDemo {
    public static void main(String[] args) {
        //创建集合对象
        Map<String, String> map = new HashMap<>();

        //添加元素
        map.put("张无忌", "赵敏");
        map.put("郭靖", "黄蓉");
        map.put("杨过", "小龙女");

        //获取所有键的集合。用keySet()方法实现
        Set<String> keySet = map.keySet();
        //遍历键的集合，获取到每一个键。用增强for实现
        for (String key : keySet) {
            //根据键去找值。用get(Object key)方法实现
            String value = map.get(key);
            System.out.println(key + "," + value);
        }
    }
}

Map集合的遍历（方式二）：

public class MapDemo {
    public static void main(String[] args) {
        //创建集合对象
        Map<String, String> map = new HashMap<String, String>();

        //添加元素
        map.put("张无忌", "赵敏");
        map.put("郭靖", "黄蓉");
        map.put("杨过", "小龙女");

        //获取所有键值对对象的集合
        Set<Map.Entry<String, String>> entrySet = map.entrySet();
        //遍历键值对对象的集合，得到每一个键值对对象
        for (Map.Entry<String, String> me : entrySet) {
            //根据键值对对象获取键和值
            String key = me.getKey();
            String value = me.getValue();
            System.out.println(key + "," + value);
        }
    }
}

斗地主案例：

public class PokerDemo {
    public static void main(String[] args) {
        //创建HashMap，键是编号，值是牌
        HashMap<Integer, String> hm = new HashMap<Integer, String>();

        //创建ArrayList，存储编号
        ArrayList<Integer> array = new ArrayList<Integer>();

        //创建花色数组和点数数组
        String[] colors = {"♦", "♣", "♥", "♠"};
        String[] numbers = {"3", "4", "5", "6", "7", "8", "9", "10", "J", "Q", "K", "A", "2"};

        //从0开始往HashMap里面存储编号，并存储对应的牌。同时往ArrayList里面存储编号
        int index = 0;

        for (String number : numbers) {
            for (String color : colors) {
                hm.put(index, color + number);
                array.add(index);
                index++;
            }
        }
        hm.put(index, "小王");
        array.add(index);
        index++;
        hm.put(index, "大王");
        array.add(index);

        //洗牌(洗的是编号)，用Collections的shuffle()方法实现
        Collections.shuffle(array);

        //发牌(发的也是编号，为了保证编号是排序的，创建TreeSet集合接收)
        TreeSet<Integer> ts1 = new TreeSet<Integer>();
        TreeSet<Integer> ts2 = new TreeSet<Integer>();
        TreeSet<Integer> ts3 = new TreeSet<Integer>();
        TreeSet<Integer> dpSet = new TreeSet<Integer>();

        for (int i = 0; i < array.size(); i++) {
            int x = array.get(i);
            if (i >= array.size() - 3) {
                dpSet.add(x);
            } else if (i % 3 == 0) {
                ts1.add(x);
            } else if (i % 3 == 1) {
                ts2.add(x);
            } else if (i % 3 == 2) {
                ts3.add(x);
            }
        }

        //调用看牌方法
        lookPoker("ts1", ts1, hm);
        lookPoker("ts2", ts2, hm);
        lookPoker("ts3", ts3, hm);
        lookPoker("底牌", dpSet, hm);
    }

    //定义方法看牌(遍历TreeSet集合，获取编号，到HashMap集合找对应的牌)
    public static void lookPoker(String name, TreeSet<Integer> ts, HashMap<Integer, String> hm) {
        System.out.print(name + "的牌是：");
        for (Integer key : ts) {
            String poker = hm.get(key);
            System.out.print(poker + " ");
        }
        System.out.println();
    }
}