這個系統主要涉及 #面向對象#錯誤測試。

1.創建圖書大類

public class Book { private String name; private int num;public Book(String name,int num){ this.name=name; this.num=num;}public String getName() {return name; }public void setName(String name) {this.name = name; }public int getNum() {return num; }public void setNum(int num) {this.num = num; }}

?2.自定義一個Exception

public class NoExistException extends Exception { public NoExistException(String message){super(message); } }

?3.主程序

import java.util.*; public class Test {Book[] book = {new Book("語文",1),new Book("數學",2),new Book("外語",3), new Book("Java編程",4)}; public List<Book> listbooks;public Test() { this.listbooks = new ArrayList<Book>(); } public void listBooksAdd() { listbooks.addAll(Arrays.asList(book)); } public void printBooks() { System.out.println("---------- 歡迎使用借書系統 ----------"); System.out.println("圖書列表展示如下："); System.out.println("序號" + "\t" + "書名");for (Book bk : listbooks) { System.out.println(bk.getNum() + "\t" + bk.getName()); } }private Scanner input = new Scanner(System.in);public static void main(String[] args) {// TODO Auto-generated method stubTest fb=new Test();fb.listBooksAdd();fb.printBooks(); System.out.println();while(true){System.out.println("請輸入您的命令：1.按名稱查找\t2.按序號查找");switch(fb.wr()){case 2:try{System.out.println("book:"+fb.fbid());break;}catch(Exception e){System.out.println(e.getMessage());continue;}case 1:try{System.out.println("book:"+fb.fbbn());break;}catch(Exception e){System.out.println(e.getMessage());continue;}default:System.out.println("錯誤，請重新輸入");continue;}}} public String fbid()throws NoExistException{System.out.println("請輸入書 的序號");int in=input.nextInt();for(Book bk : listbooks){if(in==bk.getNum()){return book[in-1].getName();}}throw new NoExistException("序號越界，此書籍不存在！！！"); }public String fbbn()throws NoExistException{System.out.println("請輸入書的名稱");String bname=input.next();for(Book bk:listbooks){if(bname.equals(bk.getName())){return bk.getName(); }}throw new NoExistException("名稱錯誤，此書籍不存在！！！"); } public int wr(){try{int in=input.nextInt();return in;}catch(Exception e){return -1; } } }

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