Java8 利用Lambda處理List集合

List<User> list = new ArrayList<User>();
        User user1 = new User("第一位","用戶1");
        list.add(user1);
        User user2 = new User("第二位","用戶2");
        list.add(user2);
        User user3 = new User("第三位","用戶3");
        list.add(user3);
        List<String> tableNames=list.stream().map(User::getMessage).collect(Collectors.toList());
        System.out.println("輸出第一個："+tableNames);
        List<String> orders=list.stream().map(User::getOrder).collect(Collectors.toList());
        System.out.println(orders)