小弟我是菜鸟。谁帮助下。

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 + "}";    }}
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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);    }}
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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*/