定義了三個類
ErrorCodeException.java
public class ErrorCodeException extends Exception {
public ErrorCodeException(){
}
public ErrorCodeException(String message){
super(message);
}
}
NoExitBookException.java
public class NoExitBookException extends Exception {
public NoExitBookException() {
}
public NoExitBookException(String message) {
super(message);
}
}
BorrowBookSystem.java
public class BorrowBookSystem {
String[] library = {"Java", "Python", "javascript", "Android", "iOS", "Linux", "Unix", "C", "C++", "C#", "Ruby", "Django", "Flask"};
public static void main(String[] args) {
BorrowBookSystem system = new BorrowBookSystem();
system.borrow();
}
public void borrow() {
while (true) {
int command = 0;
try {
command = command();
} catch (ErrorCodeException e) {
System.out.println(e.getMessage());
}
if (command == 1) {
try {
queryBookName();
} catch (NoExitBookException e) {
System.out.println(e.getMessage());
}
} else if (command == 2) {
try {
queryBookCode();
} catch (ErrorCodeException e) {
System.out.println(e.getMessage());
} catch (NoExitBookException e) {
System.out.println(e.getMessage());
}
}
}
}
public int command() throws ErrorCodeException {
int result;
System.out.println("輸入查詢指令：1-按照圖書名稱查詢，2-按照圖書序列号查詢。");
Scanner scanner = new Scanner(System.in);
String command = scanner.next().trim();
if (command.equals("1")) {
result = 1;
} else if (command.equals("2")) {
result = 2;
} else {
throw new ErrorCodeException("指令輸入錯誤！請根據提示輸入數字指令！");
}
return result;
}
private void queryBookCode() throws ErrorCodeException, NoExitBookException {
System.out.println("輸入圖書序列号：");
Scanner scanner = new Scanner(System.in);
String next = scanner.next().trim();
int number;
try {
number = Integer.parseInt(next);
} catch (Exception e) {
throw new ErrorCodeException("指令輸入錯誤！請根據提示輸入數字指令！");
}
try {
String bookName = library[number];
System.out.println("book:" + bookName);
} catch (Exception e) {
throw new ErrorCodeException("圖書不存在!");
}
}
private void queryBookName() throws NoExitBookException {
System.out.println("輸入圖書名稱：");
Scanner scanner = new Scanner(System.in);
String next = scanner.next().trim();
boolean result = false;
for (int i = 0; i < library.length; i++) {
if (library[i].equals(next)) {
System.out.println("book:" + library[i]);
result = true;
break;
}
}
if (!result) {
throw new NoExitBookException("圖書不存在!");
}
}
}