前言：

每日一點點，先貼程式碼再說！

程式碼：

@Data@ToString@AllArgsConstructor@NoArgsConstructorstatic class User {    private Integer id;    private String name;}public static void main(String[] args) {    // 構造陣列    User[] userArray = {new User(1, "1"), new User(2, "2")};    System.out.println(Arrays.toString(userArray));    // 一般寫法    Arrays.sort(userArray, new Comparator<User>() {        public int compare(User u1, User u2) {            if (u1.id < u2.id) {                return 1;            } else if (u1.id > u2.id) {                return -1;            }            return 0;        }    });    System.out.println(Arrays.toString(userArray));    // 簡寫方式1    Arrays.sort(userArray, (User u1, User u2) -> {        return u1.name.compareTo(u2.name);    });    System.out.println(Arrays.toString(userArray));    // 簡寫方式2    Arrays.sort(userArray, (a, b) -> {        return b.name.compareTo(a.name);    });    System.out.println(Arrays.toString(userArray));}

@Data@ToString@AllArgsConstructor@NoArgsConstructorstatic class User {    private Integer id;    private String name;}public static void main(String[] args) {    // 構造List    List<User> userList = Arrays.asList(new User(1, "1"), new User(2, "2"));    System.out.println(userList);    // 一般寫法    Collections.sort(userList, new Comparator<User>() {        @Override        public int compare(User u1, User u2) {            if (u1.id < u2.id) {                return 1;            } else if (u1.id > u2.id) {                return -1;            }            return 0;        }    });    System.out.println(userList);    // 簡寫方式1    Collections.sort(userList,(User u1,User u2)->{        return u1.name.compareTo(u2.name);    });    System.out.println(userList);    // 簡寫方式2    Collections.sort(userList,(u1,u2)->{        return u2.name.compareTo(u1.name);    });    System.out.println(userList);}