1.编写一个Java程序，定义一个表示学生的类，类名Student，其成员变量有：学号、班级姓名、性别、年龄； 成员方法：(1)获得班号(2)获得姓名(3)获得年龄(4)修改年龄；创建一个Student的对象，修改该对象的年龄，并输出该对象的年龄。

public class Student {
    private String stuId;
    private String className;
    private String gender;
    private int age;
    
    public Student(String stuId, String className, String gender, int age) {
        this.stuId = stuId;
        this.className = className;
        this.gender = gender;
        this.age = age;
    }
    
    public String getClassName() {
        return className;
    }
    
    public String getStuName() {
        return stuId;
    }
    
    public int getAge() {
        return age;
    }
    
    public void setAge(int age) {
        this.age = age;
    }
    
    public static void main(String[] args) {
        Student student = new Student("001", "ClassA", "Male", 20);
        student.setAge(21);
        System.out.println(student.getAge());
    }
}