困擾了一晚上的Scanner，還是不知道在哪里close？
package com.imooc;
import java.util.Scanner;
public class LibraryTest {
private static String[] books = new String[] {"語文", "數學", "英文", "政治", "歷史", "物理", "化學"};
public static void main(String[] args) {
LibraryTest lt = new LibraryTest();
while(lt.searchBook() != 0)? // 進入查找圖書系統
System.out.println("圖書不存在！");
}
public int searchBook() {
int ret = -1;
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");
try {
Scanner input = new Scanner(System.in);
int cmd = input.nextInt();
switch (cmd) {
case 1:
ret = searchBookByName();
break;
case 2:
ret = searchBookByIndex();
break;
default:
System.out.println("命令輸入錯誤！請根據提示輸入數據命令");
break;
}
} catch(Exception e) {
System.out.println("命令輸入錯誤！請根據提示輸入數據命令");
}
return ret;
}
private int searchBookByName() {
System.out.println("輸入圖書名稱：");
Scanner input = new Scanner(System.in);
String name = input.nextLine();
for (String book : books) {
if (book.equals(name)) {
System.out.println("book: " + name);
return 0;
}
}
return -1;
}
private int searchBookByIndex() {
System.out.println("輸入圖書序號：");
Scanner input = new Scanner(System.in);
int index = input.nextInt();
if (index >= 0 && index < books.length) {
System.out.println("book: " + books[index]);
return 0;
}
return -1;
}
}
2020-10-08
你每次成功執行返回的是0，然后你循環的條件是！=0，所以會退出。
樓上整理i了
2020-07-23
我看著頭大 幫忙整理一下 希望能夠幫助解答者
package?com.imooc;?? import?java.util.Scanner;?? ?? public?class?LibraryTest?{?? ?? ????private?static?String[]?books?=?new?String[]?{?"語文",?"數學",?"英文",?"政治",?? ????????????"歷史",?"物理",?"化學"?};?? ?? ????public?static?void?main(String[]?args)?{?? ????????????LibraryTest?lt?=?new?LibraryTest();?? ????????????while?(lt.searchBook()?!=?0)?? ????????????//?進入查找圖書系統?? ????????????System.out.println("圖書不存在！");?? ????}?? ?? ????public?int?searchBook()?{?? ????????int?ret?=?-1;?? ????????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");?? ????????try?{?? ????????????Scanner?input?=?new?Scanner(System.in);?? ????????????int?cmd?=?input.nextInt();?? ????????????switch?(cmd)?{?? ????????????case?1:?? ????????????????ret?=?searchBookByName();?? ????????????????break;?? ????????????case?2:?? ????????????????ret?=?searchBookByIndex();?? ????????????????break;?? ????????????default:?? ????????????????System.out.println("命令輸入錯誤！請根據提示輸入數據命令");?? ????????????????break;?? ????????????}?? ????????}?catch?(Exception?e)?{?? ????????????System.out.println("命令輸入錯誤！請根據提示輸入數據命令");?? ????????}?? ????????return?ret;?? ????}?? ?????? ????private?int?searchBookByName()?{?? ????????System.out.println("輸入圖書名稱：");?? ????????Scanner?input?=?new?Scanner(System.in);?? ????????String?name?=?input.nextLine();?? ????????for?(String?book?:?books)?{?? ????????????if?(book.equals(name))?{?? ????????????????System.out.println("book:?"?+?name);?? ????????????????return?0;?? ????????????}?? ????????}?? ????????return?-1;?? ????}?? ?????? ????private?int?searchBookByIndex()?{?? ????????System.out.println("輸入圖書序號：");?? ????????Scanner?input?=?new?Scanner(System.in);?? ????????int?index?=?input.nextInt();?? ????????if?(index?>=?0?&&?index?<?books.length)?{?? ????????????System.out.println("book:?"?+?books[index]);?? ????????????return?0;?? ????????}?? ????????return?-1;?? ????}?? ?????? }