面试题：Java中Stream sorted方法对自定义对象的排序

Question

假设有一个自定义类Student，包含属性name（字符串类型）和age（整型）。请使用Java Stream的sorted方法，先按age升序排序，如果age相同则按name的字典序升序排序，写出具体代码实现。

Answer 1

import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;

class Student {
    private String name;
    private int age;

    public Student(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public int getAge() {
        return age;
    }

    @Override
    public String toString() {
        return "Student{" +
                "name='" + name + '\'' +
                ", age=" + age +
                '}';
    }
}

public class Main {
    public static void main(String[] args) {
        List<Student> studentList = new ArrayList<>();
        studentList.add(new Student("Alice", 20));
        studentList.add(new Student("Bob", 18));
        studentList.add(new Student("Charlie", 20));

        List<Student> sortedList = studentList.stream()
               .sorted(Comparator.comparingInt(Student::getAge)
                       .thenComparing(Student::getName))
               .toList();

        sortedList.forEach(System.out::println);
    }
}