屌炸天，JDK8的排序大法！！

public class Test {
    public static void main(String\[\] args) {
        List<User> list = initList();  
        // jdk8之前的排序
        Collections.sort(list, new Comparator<User>() {
            @Override
            public int compare(User o1, User o2) {
                return o1.getAge().compareTo(o2.getAge());
            }
        });
        // jdk8 lambda排序，带参数类型
        list = initList();
        list.sort((User u1, User u2) -> u1.getAge().compareTo(u2.getAge()));
        list.forEach(System.out::println);
        System.out.println();
        // jdk8 lambda排序，不带参数类型
        list = initList();
        list.sort((u1, u2) -> u1.getAge().compareTo(u2.getAge()));
        list.forEach(System.out::println);
        System.out.println();
        // jdk8 排序，User类静态方法引用
        list = initList();
        list.sort(User::compareAge);
        list.forEach(System.out::println);
        System.out.println();
        // jdk8 升序排序，Comparator提供的静态方法
        list = initList();
        Collections.sort(list, Comparator.comparing(User::getAge));
        list.forEach(System.out::println);
        System.out.println();
        // jdk8 降序排序，Comparator提供的静态方法
        list = initList();
        Collections.sort(list, Comparator.comparing(User::getAge).reversed());
        list.forEach(System.out::println);
        System.out.println();
        // jdk8 组合排序，Comparator提供的静态方法，先按年纪排序，年纪相同的按名称排序
        list = initList();
        Collections.sort(list, Comparator.comparing(User::getAge).thenComparing(User::getName));
        list.forEach(System.out::println);
    }
    private static List<User> initList() {
        List<User> list = new ArrayList<>();
        list.add(new User("lisa", 23));
        list.add(new User("tom", 11));
        list.add(new User("john", 16));
        list.add(new User("jennis", 26));
        list.add(new User("tin", 26));
        list.add(new User("army", 26));
        list.add(new User("mack", 19));
        list.add(new User("jobs", 65));
        return list;
    }
}