package exception_demo;

import java.util.Scanner;

public class Book {

public static void main(String[] args) {

// TODO Auto-generated method stub

Book bookObj = new Book();

bookObj.init();

}

public void init() {

String[] books = {"java","php","python","go"};

int type;

String BookName;

try {

type = searchType();

if(type == 1) {

BookName = searchBookName(books);

}else {

BookName = searchBookNum(books);

}

System.out.println("book:"+BookName);

}catch(BookException e) {

System.out.println(e.getMessage());

init();

}catch(Exception e) {

System.out.println(e.getMessage());

init();

}

}

//通过哪种类型选择图书

public int searchType() throws BookException {

Scanner input = new Scanner(System.in);//创建scanner对象

System.out.print("请输入命令：1-按照名称查找图书；2-按照序号查找图书");

int type = input.nextInt();

if(type == 1 || type == 2) {

return type;

}else{

throw new BookException("命令输入错误！请根据提示输入数字命令！");

}

}

//通过名称查找

public String searchBookName(String[] books) throws Exception {

Scanner input = new Scanner(System.in);//创建scanner对象

System.out.println("请输入图书名称:");

String BookName = input.next();

for(String book :  books) {

if(book.equals(BookName)) {

return BookName;

}

}

throw new Exception("图书不存在!");

}

//通过序号查找

public String searchBookNum(String[] books) throws Exception {

Scanner input = new Scanner(System.in);//创建scanner对象

System.out.println("请输入图书序号:");

int BookNum = input.nextInt();

if(BookNum < books.length && BookNum >= 0) {

return books[BookNum-1];

}

throw new Exception("图书不存在!");

}

}

package exception_demo;

public class BookException extends Exception{

public BookException(String message) {

super(message);

}

}