package?library;
import?java.util.InputMismatchException;
import?java.util.Scanner;
public?class?tushu?{
?public?static?String[]?books?=?{?"高數",?"代數",?"英語",?"語文"?};
?public?static?String?byBookName(String?filterName)?{
??for?(String?book?:?books)?{
???if?(book.contains(filterName))?{
????return?book;
???}
??}
??return?"不存在";
?}
?public?static?String?byBookID(int?bookID)?{
??return?books[bookID?-?1];
?}
?public?static?void?main(String[]?args)?{
??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?scanner?=?new?Scanner(System.in);
??//?當輸入的值為非1和非2的時候，?提示重新輸入!
??int?filterType?=?0;
??int?i?=?0;
??do?{
???if?(i?!=?0)?{
????System.out.println("命令輸入錯誤！?請根據提示輸入數字命令！");
???}
???i++;
???try?{
????filterType?=?scanner.nextInt();
???}?catch?(InputMismatchException?e)?{
????scanner?=?new?Scanner(System.in);
???}
??}?while?(filterType?!=?1?&&?filterType?!=?2);
??
??//進入查找圖書的流程
??if?(filterType?==?1)?{
???System.out.println("輸入圖書名稱：");
???String?bookName?=?byBookName(scanner.next());
???if?(bookName.equals("不存在"))?{
????System.out.println("圖書不存在！");
???}?else?{
????System.out.println("book:"?+?bookName);
???}
??}?else?{
???System.out.println("輸入圖書序號：");
???try?{
????String?bookName?=?byBookID(scanner.nextInt());
????System.out.println("book:"?+?bookName);
???}?catch?(InputMismatchException?e)?{
????System.out.println("輸入類型錯誤，?拋出錯誤命令異常，?提示重新輸入");
???}?catch?(ArrayIndexOutOfBoundsException?e)?{
????System.out.println("圖書不存在！");
???}
???scanner.close();
??}
?}
}

?

老師的代碼

while?(true)?{
???System.out.println("輸入圖書序號：");
???try?{
????//獲取輸入的圖書序號（數組下標）
????int?index?=?inputCommand();
????//若返回值為-1
????if(index?==?-1){
?????System.out.println("命令輸入錯誤！請根據提示輸入數字命令！");
?????continue;
????}
????//若不出現”數組下標越界異常“，則返回相應位置的圖書
????String?book?=?books[index];
????return?book;
???}?catch?(ArrayIndexOutOfBoundsException?e)?{
????//輸入的序號不存在（引發”數組下標越界異常“），則拋出”圖書不存在異常“
????Exception?bookNotExists?=?new?Exception("圖書不存在！");
????bookNotExists.initCause(e);
????throw?bookNotExists;
???}
??}