学生管理系统——2

package com.jsu.stu;

public class Student {
     private  String ID;
     private  String name;
     private  int age;

    public Student() {
    }

    public Student(String name, String ID, int age) {
        this.name = name;
        this.ID = ID;
        this.age = age;
    }

    public String getName() {
        return name;
    }

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

    public String getID() {
        return ID;
    }

    public void setID(String ID) {
        this.ID = ID;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }
}

package com.jsu.stu;

import java.util.ArrayList;
import java.util.Scanner;

public class StudentTest {
    public static void main(String[] args) {

        ArrayList<Student>list=new ArrayList<>();

        Choose:while (true) {
            System.out.println("----------------------欢迎来到学生管理系统-----------------------");
            System.out.println("1：添加学生");
            System.out.println("2：删除学生");
            System.out.println("3：查询学生");
            System.out.println("4：修改学生");
            System.out.println("5：退出");
            System.out.println("请输入你的选择：");

            Scanner scan = new Scanner(System.in);
            String number = scan.next();

            switch (number){
                case "1"-> Tianjia(list);
                case "2"-> shanchu(list);
                case "3"-> chaxun(list);
                case "4"-> xiugai(list);
                case "5"-> {
                    System.out.println("退出");
                    break Choose;
                }
                default -> System.out.println("退出此学生系统");
                }
            }
        }
        //添加学生——方法
        public static void Tianjia(ArrayList<Student>list){
          Student person=new Student();




          Scanner scan = new Scanner(System.in);


            while (true) {
                System.out.println("请填入学生的ID：");
                String ID= scan.next();
                person.setID(ID);
                boolean flag=panDuan(list,ID);
                if(flag){
                    System.out.println("这个ID已存在，请重新输入");
                }
                 else{
                     person.setID(ID);
                     break;
                }
            }


            System.out.println("请填入学生的姓名：");
            String name= scan.next();
            person.setName(name);

            System.out.println("请填入学生的年龄：");
            int age = scan.nextInt();
            person.setAge(age);

            list.add(person);

            System.out.println("学生添加成功");
        }

        //删除学生——方法
        public static void shanchu(ArrayList<Student>list){
            System.out.println("请输入要删除学生的ID：");
            Scanner scan = new Scanner(System.in);
            String id = scan.next();
            int Num=num(list,id);
            if(Num>0){
                list.remove(Num);
                System.out.println("删除成功");
            }
            else{
                System.out.println("id不存在，请重新输入");
            }
        }


        //查询学生——方法
        public static void chaxun(ArrayList<Student>list){

             if(list.size()==0){
                 System.out.println("当前无学生信息，请添加学生再查询");

             }

             else{
                 for (int i = 0; i < list.size(); i++) {
                     Student stu=list.get(i);

                     System.out.println(stu.getID()+"  "+stu.getName()+"  "+stu.getAge());
                 }
             }
        }

        //修改学生——方法
        public static void xiugai(ArrayList<Student>list){

        Scanner scan = new Scanner(System.in);
            System.out.println("请输入要修改学生的id：");
        String id=scan.next();
        int Num=num(list,id);
        if(Num==0){
            System.out.println("id不存在，请重新输入");
            return;
        }

            Student s=list.get(Num);
            System.out.println("请输入要修改的学生姓名");
            String newName= scan.next();
            s.setName(newName);
            System.out.println("要修改的学生年龄");
            int newAge= scan.nextInt();
            s.setAge(newAge);
            System.out.println("学生信息修改成功");

        }


        public static boolean panDuan(ArrayList<Student>list,String ID){
            for (int i = 0; i < list.size(); i++) {
                Student stu = list.get(i);
                String sid = stu.getID();
                if(sid.equals(ID)){
                    return true;
                }
            }
            return false;
        }

        public static int num(ArrayList<Student>list,String ID) {
            for (int i = 0; i < list.size(); i++) {
                Student stu = list.get(i);
                String studentID = stu.getID();
                if (studentID.equals(ID)) {
                    return i;
                }
            }
            return 0;
        }
    }