用java定义类Student，包含三个属性：学号number(int)，年级state(int).成绩score(int)。创建20个学生对象，学号为1到20，年级和成绩都由随机数确定。问题一：打印出3年级（state值为3）的学生信息。 问题二：使用冒泡排序按学生成绩排序，并遍历所有学生信息

好的，我会为您解答这两个问题。

问题一：打印出3年级（state值为3）的学生信息。

import java.util.Random;

public class Student {
    private int number;
    private int state;
    private int score;
    
    public Student(int number, int state, int score) {
        this.number = number;
        this.state = state;
        this.score = score;
    }
    
    public int getNumber() {
        return number;
    }
    
    public int getState() {
        return state;
    }
    
    public int getScore() {
        return score;
    }
    
    public static void main(String[] args) {
        // 创建20个学生对象
        Student[] students = new Student[20];
        Random random = new Random();
        for (int i = 0; i < 20; i++) {
            students[i] = new Student(i + 1, random.nextInt(6) + 1, random.nextInt(101));
        }
        
        // 打印出3年级的学生信息
        System.out.println("3年级的学生信息如下：");
        for (int i = 0; i < 20; i++) {
            if (students[i].getState() == 3) {
                System.out.println("学号：" + students[i].getNumber() + "，年级：" + students[i].getState() + "，成绩：" + students[i].getScore());
            }
        }
    }
}

问题二：使用冒泡排序按学生成绩排序，并遍历所有学生信息

import java.util.Random;

public class Student {
    private int number;
    private int state;
    private int score;
    
    public Student(int number, int state, int score) {
        this.number = number;
        this.state = state;
        this.score = score;
    }
    
    public int getNumber() {
        return number;
    }
    
    public int getState() {
        return state;
    }
    
    public int getScore() {
        return score;
    }
    
    public static void main(String[] args) {
        // 创建20个学生对象
        Student[] students = new Student[20];
        Random random = new Random();
        for (int i = 0; i < 20; i++) {
            students[i] = new Student(i + 1, random.nextInt(6) + 1, random.nextInt(101));
        }
        
        // 使用冒泡排序按学生成绩排序
        for (int i = 0; i < 19; i++) {
            for (int j = 0; j < 19 - i; j++) {
                if (students[j].getScore() > students[j + 1].getScore()) {
                    Student temp = students[j];
                    students[j] = students[j + 1];
                    students[j + 1] = temp;
                }
            }
        }
        
        // 遍历所有学生信息
        System.out.println("所有学生信息如下：");
        for (int i = 0; i < 20; i++) {
            System.out.println("学号：" + students[i].getNumber() + "，年级：" + students[i].getState() + "，成绩：" + students[i].getScore());
        }
    }
}