模擬借書系統簡易版（慕課網java入門第三季異常）

package com.imooc.book;

import java.util.InputMismatchException;
import java.util.Scanner;

public class Book {
    String bName;
    int bNum;
    public static   Book[]bookList = new Book[5];

    public Book(){

    }
    public Book(String name,int num){
        bName = name;
        bNum = num;

    }
    public void FindByName(String name){
        for(int i=0;i<bookList.length;i++){
            if(bookList[i].bName.equals(name)){
            System.out.println("book:"+name);
            return;
        }
        }
        System.out.println("圖書不存在");

    }
    public void FindByNum(int num){
        for(int i=0;i<bookList.length;i++){
            if(bookList[i].bNum==num){
                System.out.println("book"+bookList[i].bName);
                return;

            }
        }
        System.out.println("圖書不存在");
    }

    public static void main(String[]args){
        Book book = new Book();
        Book.bookList[0]=new Book("高數",1);
        Book.bookList[1]=new Book("大物",2);
        Book.bookList[2]= new Book("線代",3);
        Book.bookList[3]=new Book("英語",4);
        Book.bookList[4]=new Book("化學",5);

        while(true){
            System.out.println("輸入命令：1-按照名稱查找圖書；2-按照序號查找圖書");
            Scanner scan = new Scanner(System.in);
            try{
                int cmd = scan.nextInt();
                scan.nextLine();
                switch(cmd){
                    case 1:
                            System.out.println("輸入圖書名稱：");
                            String name = scan.nextLine();
                            book.FindByName(name);
                            scan.close();
                            break;

                    case 2:
                        System.out.println("輸入圖書序號：");
                        int num = scan.nextInt();
                        scan.nextLine();
                        book.FindByNum(num);
                        scan.close();
                        break;

                    default:
                        System.out.println("命令輸入錯誤！請根據提示輸入數字命令！");

                }   
            }catch(InputMismatchException e){
            //e.printStackTrace();
            System.out.println("命令輸入錯誤！請根據提示輸入數字命令！");
            }
        }
    }
}

注意Scanner類的nextInt函數，只會取走數字，不會取走‘\r’導致下一次next()函數得到的是‘\r’，而不是要取的內容。