Java中Comparator進行對象排序

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Java在8後引入了lambda運算式和流，使得排序方法有了變化

class User {    int id;    String name;    public User(int id, String name) {        this.id = id;        this.name = name;    }    public int getId() {        return id;    }    public String getName() {        return name;    }    @Override    public String toString() {        return "User{" + "id=" + id + ", name=‘" + name + ‘\‘‘ + ‘}‘;    }}List<String> words = Arrays.asList("566ggg", "ce", "ddd", "dc", "cds", "cece");        //使用list的sort方法        words.sort(Comparator.comparingInt(String::length).thenComparing((String.CASE_INSENSITIVE_ORDER)));        System.out.println(words);        //使用Collections工具類 三種方法等價        Collections.sort(words, (s1, s2) -> Integer.compare(s1.length(), s2.length()));        Collections.sort(words, Comparator.comparing(word -> word.length()));        Collections.sort(words, new Comparator<String>() {            public int compare(String s1, String s2) {                return Integer.compare(s1.length(), s2.length());            }        });        System.out.println(words);        List<User> userList = new ArrayList<>();        userList.add(new User(45, "lili"));        userList.add(new User(45, "abcd"));        userList.add(new User(41, "bbde"));        userList.add(new User(43, "cdef"));        userList.sort(Comparator.comparing(User::getId).thenComparing(User::getName));        System.out.println(userList);

輸出結果：

[ce, dc, cds, ddd, cece, 566ggg][ce, dc, cds, ddd, cece, 566ggg][User{id=41, name=‘bbde‘}, User{id=43, name=‘cdef‘}, User{id=45, name=‘abcd‘}, User{id=45, name=‘lili‘}]

Java中Comparator進行對象排序