快递管理训练任务--通过集合存储数据

![在这里插入图片描述](https://img-blog.csdnimg.cn/20210209234531220.png#pic_center

我利用了map同时存储了公司名称，取件码和订单号
package com.java.text;

import java.util.*;

public class Demo1 {
static Scanner input = new Scanner(System.in);

public static void main(String[] args) {
    Express e = new Express();
    int over = 0;
    while (true) {
        System.out.println("请输入您的身份");
        System.out.println("1,快递员");
        System.out.println("2.用户");
        int c = input.nextInt();
        if (c == 1) {
            System.out.println("请选择您的功能");
            System.out.println("1.增加快递2.删除快递3.修改快递4.查看所有快递5.退出");
            int c1 = input.nextInt();
            switch (c1) {
                case 1:
                    e.serve();
                    break;
                case 2:
                    e.delete();
                    break;
                case 3:
                    e.correction();
                    break;
                case 4:
                    e.check();
                    break;
                case 5:
                    over = 1;
            }
            if (over == 1)
                break;
        } else {
            e.userget();
            break;
        }
    }
}

static class Express {
    static Scanner input = new Scanner(System.in);
    HashMap<Integer, Integer> number = new HashMap<>();
    HashMap<Integer, String> map = new HashMap<>();

    int serve() {
        int key;
        System.out.println("请输入快递号");
        try {
            Scanner input = new Scanner(System.in);
            key = input.nextInt();
        }catch (InputMismatchException e){
            System.out.println("输入的不是数字");
            return serve();
        }
        System.out.println("请输入快递公司");
        String company = input.next();
        String i = map.put(key, company);
        int numbers = (int) (Math.random() * (65535 + 1) * 10);
        number.put(key,numbers);
        if (i != null) {
            System.out.println("该快递号已经有快递了请重新输入");
            map.put(key, i);
            return serve();
        }
        return 0;
    }

    void delete() {
        System.out.println("请输入要删除的快递单号(若是修改快递删除已经有的快递)");
        int key = input.nextInt();
        String i = map.remove(key);
        number.remove(key);
        if (i == null) {
            System.out.println("此快递单号本就没快递sb（帅逼）");
        } else
            System.out.println("删除成功");
    }

    void correction() {
        System.out.println("请输入要修改的快递单号");
        delete();
        serve();
    }

    void check() {
        Set<Integer> set = map.keySet();
        for (Integer key : set) {
            System.out.println("订单号为"+key + "，公司为" + map.get(key) );
            System.out.println("取件码为"+number.get(key));
        }
    }

    int userget() {
        System.out.println("请输入取件码");
        int numbers;
        try{  Scanner input = new Scanner(System.in);
            numbers = input.nextInt();
        }
        catch (InputMismatchException e){
            System.out.println("输入的不是数字");
            return userget();
        }
        Set<Integer> set = map.keySet();
        for (Integer key : set) {
            if (numbers == number.get(key)) {
                System.out.println("订单号为" + key + "，公司为" + map.remove(key));
                return 0;
            }
        }
        System.out.println("输入错误请检查后重新输入");
        return userget();
    }
}

}

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