定义一个存放在包com.xhu下的包含学生学号、姓名和成绩的类Student，类中覆盖了toString()方法，toString()方法将学生信息以字符串的方式返回。然后再编写一个存放于com.test的测试类，类中对n个学生(n个Student类对象)的成绩进行升序排列并输出排序后的结果。

以下是定义类Student和测试类的完整代码：

Student类：

package com.xhu;

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

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

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public float getScore() {
        return score;
    }

    public void setScore(float score) {
        this.score = score;
    }

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

测试类：

package com.test;

import com.xhu.Student;

import java.util.Arrays;

public class Test {
    public static void main(String[] args) {
        // 创建n个学生
        int n = 5;
        Student[] students = new Student[n];
        students[0] = new Student("1001", "张三", 85);
        students[1] = new Student("1002", "李四", 90);
        students[2] = new Student("1003", "王五", 70);
        students[3] = new Student("1004", "赵六", 80);
        students[4] = new Student("1005", "陈七", 95);

        // 对学生的成绩进行升序排序
        Arrays.sort(students, (o1, o2) -> Float.compare(o1.getScore(), o2.getScore()));

        // 输出排序后的结果
        System.out.println("排序后的结果：");
        for (Student student : students) {
            System.out.println(student);
        }
    }
}

执行该测试类的main方法会输出如下结果：

排序后的结果：
Student{id='1003', name='王五', score=70.0}
Student{id='1004', name='赵六', score=80.0}
Student{id='1001', name='张三', score=85.0}
Student{id='1002', name='李四', score=90.0}
Student{id='1005', name='陈七', score=95.0}