class Student {
    private Integer stuId;// 學號
    private String name;// 姓名
    private Boolean gender;// 性別
    private String address;// 地址
    private String gradeNo;// 級
    private String classNo;// 班

    // 無參構造函數
    public Student() {
    }

    // 全參構造函數
    public Student(Integer stuId, String name, Boolean gender, String address, String gradeNo, String classNo) {
        this.stuId = stuId;
        this.name = name;
        this.gender = gender;
        this.address = address;
        this.gradeNo = gradeNo;
        this.classNo = classNo;
    }

    public Integer getStuId() {
        return stuId;
    }

    public void setStuId(Integer stuId) {
        this.stuId = stuId;
    }

    public String getName() {
        return name;
    }

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

    public Boolean getGender() {
        return gender;
    }

    public void setGender(Boolean gender) {
        this.gender = gender;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    public String getGradeNo() {
        return gradeNo;
    }

    public void setGradeNo(String gradeNo) {
        this.gradeNo = gradeNo;
    }

    public String getClassNo() {
        return classNo;
    }

    public void setClassNo(String classNo) {
        this.classNo = classNo;
    }

    @Override
    public String toString() {
        return "{stuId:" + this.stuId + ",name:" + this.name + "}";
    }
}

------解决方案--------------------

Java code

public class Student {

    private int studentNumber;//学号
    private int studentClass;//班级
    private char sex;//性别
    private int age;//年龄

    public int getAge() {//该方法获取年龄
        return age;
    }

    public void setAge(int age) {//该方法设置年龄
        this.age = age;
    }

    public char getSex() {//该方法获取性别
        return sex;
    }

    public void setSex(char sex) {//该方法设置性别
        this.sex = sex;
    }

    public int getStudentClass() {//该方法获取班级
        return studentClass;
    }

    public void setStudentClass(int studentClass) {//该方法设置班级
        this.studentClass = studentClass;
    }

    public int getStudentNumber() {//该方法获取学号
        return studentNumber;
    }

    public void setStudentNumber(int studentNumber) {//该方法设置学号
        this.studentNumber = studentNumber;
    }

    public Student() {
    }

    public Student(int studentNumber, int studentClass, char sex, int age) {
        this.studentNumber = studentNumber;
        this.studentClass = studentClass;
        this.sex = sex;
        this.age = age;
    }

    @Override
    public String toString() {
        return "学号：" + studentNumber + "，班级：" + studentClass + "，性别：" + sex + "，年龄" + age;
    }

    public static void main(String[] args) {
        Student s1 = new Student(1, 3, '男', 21);
        System.out.println(s1);
        s1.setAge(22);
        System.out.println(s1);
    }
}

------解决方案--------------------
保存到文件吧 再从文件中读取数据 并输出

Java code

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.ArrayList;

public class Student implements Serializable{
    private int studentNumber;//学号
    private int studentClass;//班级
    private char sex;//性别
    private int age;//年龄

    public int getAge() {//该方法获取年龄
    return age;
    }

    public void setAge(int age) {//该方法设置年龄
    this.age = age;
    }

    public char getSex() {//该方法获取性别
    return sex;
    }

    public void setSex(char sex) {//该方法设置性别
    this.sex = sex;
    }

    public int getStudentClass() {//该方法获取班级
    return studentClass;
    }

    public void setStudentClass(int studentClass) {//该方法设置班级
    this.studentClass = studentClass;
    }

    public int getStudentNumber() {//该方法获取学号
    return studentNumber;
    }

    public void setStudentNumber(int studentNumber) {//该方法设置学号
    this.studentNumber = studentNumber;
    }

    public Student() {
    }

    public Student(int studentNumber, int studentClass, char sex, int age) {
    this.studentNumber = studentNumber;
    this.studentClass = studentClass;
    this.sex = sex;
    this.age = age;
    }

    @Override
    public String toString() {
    return "学号：" + studentNumber + "，班级：" + studentClass + "，性别：" + sex
        + "，年龄" + age;
    }

    public static void main(String[] args) throws Exception{

    ArrayList<Student> students = new ArrayList<Student>();
    students.add(new Student(1, 1, '男', 21));
    students.add(new Student(2, 1, '男', 21));
    students.add(new Student(3, 1, '男', 21));
    students.add(new Student(4, 1, '男', 21));
    students.add(new Student(5, 1, '男', 21));
    students.add(new Student(6, 1, '女', 21));

    ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(
        "c:/student.txt"));
    oos.writeObject(students);
    oos.close();
    ObjectInputStream ois = new ObjectInputStream(new FileInputStream(
        "c:/student.txt"));

    students = (ArrayList<Student>) ois.readObject();
    for (int i = 0; i < students.size(); i++) {
        System.out.println("*********************第" + i
            + "个学生**************************");
        System.out.println(students.get(i));
    }
    }
}
/*
 *********************第0个学生**************************
学号：1，班级：1，性别：男，年龄21
*********************第1个学生**************************
学号：2，班级：1，性别：男，年龄21
*********************第2个学生**************************
学号：3，班级：1，性别：男，年龄21
*********************第3个学生**************************
学号：4，班级：1，性别：男，年龄21
*********************第4个学生**************************
学号：5，班级：1，性别：男，年龄21
*********************第5个学生**************************
学号：6，班级：1，性别：女，年龄21
*/