定义Student学生类, 有id学号, name姓名, score成绩等属性定义List集合存储Student学生对象 向 List集合中添加 50 个Student对象, 要求id自增, 姓名随机生成, 成绩随机生成 要求使用stream流进行以下操作 1) 把集合中不及格同学的姓名保存到List集合中 2) 对list集合中的学生对象根据成绩降序排序, 如果成绩一样再根据学号升序排序, 把结果保存到Set集合中 3) 计算所有同学的平均分 4) 查看最高分同学 5) 查看最低分同学

下面是Java代码实现：

import java.util.*;
import java.util.stream.Collectors;

public class Student {
    private int id;
    private String name;
    private int score;

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

    public int getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    public int getScore() {
        return score;
    }

    public static void main(String[] args) {
        List<Student> students = new ArrayList<>();

        // 添加50个学生对象
        for (int i = 1; i <= 50; i++) {
            String name = getRandomName();
            int score = (int) (Math.random() * 101);
            Student student = new Student(i, name, score);
            students.add(student);
        }

        // 1) 把集合中不及格同学的姓名保存到List集合中
        List<String> failStudents = students.stream()
                                            .filter(s -> s.getScore() < 60)
                                            .map(Student::getName)
                                            .collect(Collectors.toList());
        System.out.println("不及格的学生有：" + failStudents);

        // 2) 对list集合中的学生对象根据成绩降序排序, 如果成绩一样再根据学号升序排序, 把结果保存到Set集合中
        Set<Student> sortedStudents = students.stream()
                                               .sorted(Comparator.comparing(Student::getScore).reversed()
                                                                 .thenComparing(Student::getId))
                                               .collect(Collectors.toCollection(LinkedHashSet::new));
        System.out.println("按照成绩排序后的学生有：" + sortedStudents);

        // 3) 计算所有同学的平均分
        double averageScore = students.stream()
                                      .mapToInt(Student::getScore)
                                      .average()
                                      .orElse(0.0);
        System.out.println("所有同学的平均分为：" + averageScore);

        // 4) 查看最高分同学
        Optional<Student> highestScoreStudent = students.stream()
                                                         .max(Comparator.comparing(Student::getScore));
        if (highestScoreStudent.isPresent()) {
            System.out.println("最高分同学是：" + highestScoreStudent.get().getName() + "，分数为：" + highestScoreStudent.get().getScore());
        }

        // 5) 查看最低分同学
        Optional<Student> lowestScoreStudent = students.stream()
                                                        .min(Comparator.comparing(Student::getScore));
        if (lowestScoreStudent.isPresent()) {
            System.out.println("最低分同学是：" + lowestScoreStudent.get().getName() + "，分数为：" + lowestScoreStudent.get().getScore());
        }
    }

    private static String getRandomName() {
        String[] firstName = {"张", "王", "李", "赵", "刘", "陈", "杨", "黄", "吴", "周", "徐", "孙", "马", "朱", "胡", "林", "郭", "何", "高", "罗"};
        String[] lastName = {"明", "红", "华", "强", "丽", "超", "涛", "艳", "峰", "秀", "勇", "磊", "莉", "军", "婷", "鹏", "萍", "伟", "敏", "飞"};
        return firstName[(int) (Math.random() * firstName.length)] + lastName[(int) (Math.random() * lastName.length)];
    }
}