可以正常输入，，但是每次重新返回菜单查询的时候又是null值了，，
我感觉是 showMemu()方法里面的创建对象，，
如果我执行了添加数据，，按1，又进入了主菜单，，又会重新创建对象数组，所以又是null了，，
请问该怎么该？
让记录会正常保存
- Java code
import java.util.*;public class Main { void input(Student s[],int n) { Scanner scan = new Scanner(System.in); System.out.println("请输入姓名："); s[n].name = scan.next(); System.out.println("请输入学号："); s[n].num = scan.nextInt(); System.out.println("请输入英语成绩："); s[n].english = scan.nextInt(); System.out.println("请输入程序设计程序："); s[n].programme = scan.nextInt(); System.out.println("请输入数学成绩："); s[n].math = scan.nextInt(); System.out.println("按1返回主菜单，按0退出"); int b = scan.nextInt(); if( b == 1) showMemu(); else System.exit(0); } void avgScore(Student s[],int n) { double average = (s[n].english + s[n].math + s[n].programme) / 3.0; System.out.println(average); Scanner scan = new Scanner(System.in); System.out.println("按1返回主菜单，按0退出"); int b = scan.nextInt(); if( b == 1) showMemu(); else System.exit(0); } void searchst(Student s[],int n) { for(int i = 0;i<s.length;i++) { if(s[i].num == n) { System.out.println("姓名：" + s[i].name); System.out.println("学号：" + s[i].num); System.out.println("英语：" + s[i].english); System.out.println("数学：" + s[i].math); System.out.println("程序设计：" + s[i].programme); break; } } Scanner scan = new Scanner(System.in); System.out.println("按1返回主菜单，按0退出"); int b = scan.nextInt(); if( b == 1) showMemu(); else System.exit(0); } void sort(Student s[]) { Arrays.sort(s); Scanner scan = new Scanner(System.in); System.out.println("按1返回主菜单，按0退出"); int b = scan.nextInt(); if( b == 1) showMemu(); else System.exit(0); } void display(Student s[]) { for(int i = 0; i < s.length;i++) { System.out.println("姓名" + s[i].name + "\t" + "学号" + s[i].num + "\t" + "英语成绩：" + s[i].english + "\t" + "程序设计成绩：" + s[i].programme + "\t" + "数学成绩：" + s[i].math); } Scanner scan = new Scanner(System.in); System.out.println("按1返回主菜单，按0退出"); int b = scan.nextInt(); if( b == 1) showMemu(); else System.exit(0); } public void showMemu() { //==================== // 显示主菜单 //==================== System.out.println("==========学籍管理系统==========\n\t" + "1.输入学生信息\n\t" + "2.求每门课平均成绩\n\t" + "3.按学号姓名查找学生\n\t" + "4.从高分到低分显示学生信息\n\t" + "5.显示学生信息" + "\n\t6.退出"); //创建对象数组 Student[] info = new Student[5]; for(int i = 0; i < info.length; i++) { info[i] = new Student(); } //创建记录号 int n = 0; //接收一个数作为选择 Scanner scan = new Scanner(System.in); int choose = scan.nextInt(); switch (choose) { case 1: input(info, n); n++; case 2: System.out.println("请输入你要求平均分的学生：（0为第一条记录）"); int num = scan.nextInt(); avgScore(info, num); case 3: System.out.println("请输入您查询的学号："); int num1 = scan.nextInt(); searchst(info, num1); case 4: sort(info); case 5: display(info); case 6: System.exit(0); } } public static void main(String[] args) { Main m = new Main(); Student[] info = new Student[5]; for(int i = 0; i < info.length; i++) { info[i] = new Student(); } m.showMemu(); }}