来交作业了

import java.util.Scanner;

public class Initial {

String  [] BookList=new String[] {"高数","Java","数据结构","C++","计算机网络"};

public static void main(String[] args) {

Initial init=new Initial();

init.start();

}

public void start() {

   int a=1;

ChooseMethod();

}

public void ChooseMethod() {

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

Scanner methodinput=new Scanner(System.in);

try {

int method=methodinput.nextInt();

if(method==1)

SearchByName();

if (method==2)

SearchByNumber();

} catch (NameException e) {

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

start();

}catch (NumberException e) {

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

start();

}catch (Exception e) {

System.out.println("命令输入错误！请按照提示输入数字命令！");

start();

}

}

public void SearchByNumber() throws NumberException{

System.out.println("输入图书序号：");

Scanner BookNumberInput=new Scanner(System.in);

int BookNumber = 0;

try {

BookNumber = BookNumberInput.nextInt();

} catch (Exception e) {

System.out.println("命令输入错误！请按照提示输入数字命令！");

SearchByNumber();

}

if(BookNumber<=BookList.length)

System.out.println("book:"+BookList[BookNumber-1]);

else

throw new NumberException();

}

public void SearchByName() throws NameException{

System.out.println("输入图书名称：");

Scanner BooknameInput=new Scanner(System.in);

String Bookname=BooknameInput.nextLine();

Boolean check=false;

for(int i=0;i<BookList.length;i++) {

if(BookList[i].equals(Bookname))

{

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

check=true;

}

}

if(check==false)

throw new NameException();

}

}

public class NameException extends Exception{

NameException(){

super("图书不存在！");

}

}

public class NumberException extends Exception{

public NumberException() {

super("图书不存在！");

}

}