Java中List.sort()自定义排序规则几种方式

List<String> list = Arrays.asList("banana", "apple", "pear", "orange");
list.sort(new Comparator<String>() {
    @Override
    public int compare(String s1, String s2) {
        return s1.length() - s2.length(); // 按字符串长度排序
    }
});

List<String> list = Arrays.asList("banana", "apple", "pear", "orange");
list.sort((s1, s2) -> s1.length() - s2.length()); // 按字符串长度排序

List<String> list = Arrays.asList("banana", "apple", "pear", "orange");

// 按字符串长度排序
list.sort(Comparator.comparingInt(String::length));

// 先按长度，再按字母顺序
list.sort(Comparator.comparingInt(String::length).thenComparing(Comparator.naturalOrder()));

class Person {
    String name;
    int age;
    
    // 构造方法、getter/setter省略
}

List<Person> people = Arrays.asList(
    new Person("Alice", 25),
    new Person("Bob", 20),
    new Person("Charlie", 30)
);

// 按年龄排序
people.sort(Comparator.comparingInt(Person::getAge));

// 按年龄降序
people.sort(Comparator.comparingInt(Person::getAge).reversed());

// 多条件排序：先按姓名，再按年龄
people.sort(Comparator.comparing(Person::getName).thenComparingInt(Person::getAge));

class Person implements Comparable<Person> {
    String name;
    int age;
    
    @Override
    public int compareTo(Person other) {
        return this.age - other.age; // 按年龄排序
    }
}

List<Person> people = new ArrayList<>();
// 添加元素...
people.sort(null); // 使用自然排序