【Java基础】Collections集合概述和使用、ArrayList集合存储学生并排序及斗地主案例

public class CollectionsDemo01 { 
    public static void main(String[] args) { 
        //创建集合对象 
        List<Integer> list = new ArrayList<Integer>(); 
        //添加元素 
        list.add(30); 
        list.add(20); 
        list.add(50); 
        list.add(10); 
        list.add(40); 
        //public static <T extends Comparable<? super T>> void sort•(List<T> list)：将指定的列表按升序排序
         Collections.sort(list); 
        //public static void reverse•(List<?> list)：反转指定列表中元素的顺序 
         Collections.reverse(list); 
        //public static void shuffle•(List<?> list)：使用默认的随机源随机排列指定的列表 
        Collections.shuffle(list); 
        System.out.println(list); 
    } 
}

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; 
    } 
}

public class CollectionsDemo02 { 
    public static void main(String[] args) { 
        //创建ArrayList集合对象 
        ArrayList<Student> array = new ArrayList<Student>(); 
        //创建学生对象 
        Student s1 = new Student("linqingxia", 30); 
        Student s2 = new Student("zhangmanyu", 35); 
        Student s3 = new Student("wangzuxian", 33); 
        Student s4 = new Student("liuyan", 33); 
        //把学生添加到集合 
        array.add(s1); 
        array.add(s2); 
        array.add(s3); 
        array.add(s4); 
        //使用Collections对ArrayList集合排序 
        //sort•(List<T> list, Comparator<? super T> c) 
        Collections.sort(array, new Comparator<Student>() { 
            @Override 
            public int compare(Student s1, Student s2) { 
                //按照年龄从小到大排序，年龄相同时，按照姓名的字母顺序排序 
                int num = s1.getAge() - s2.getAge(); 
                int num2 = num == 0 ? s1.getName().compareTo(s2.getName()) : num; 
                return num2; 
            } 
        }); 
        //遍历集合 
        for (Student s : array) { 
            System.out.println(s.getName() + "," + s.getAge()); 
        } 
    } 
}

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> lqxSet = new TreeSet<Integer>(); 
        TreeSet<Integer> lySet = new TreeSet<Integer>(); 
        TreeSet<Integer> fqySet = 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) { 
                lqxSet.add(x); 
            } else if (i % 3 == 1) { 
                lySet.add(x); 
            } else if (i % 3 == 2) { 
                fqySet.add(x); 
            } 
        }
        //调用看牌方法 
        lookPoker("林青霞", lqxSet, hm); 
        lookPoker("柳岩", lySet, hm); 
        lookPoker("风清扬", fqySet, 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(); 
    } 
}