---------------------------------------------------------------------

//自定义的异常

public class ErrorMinException extends Exception{

public ErrorMinException() {

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

}

}

--------------------------------------------------------------------

//自定义的异常

public class BookDoesNotExistException extends Exception{

public BookDoesNotExistException() {

System.out.println("图书不存在！");

}

}

------------------------------------------------------------------------

//主要的东西

import java.util.Scanner;

public class BookTest {

//主方法里就定义了一个数组，然后是选择怎样找书的方法

public static void main(String[] args) {

// TODO Auto-generated method stub

String[] Books = {"c","c++","java","python","js"};

select(Books);

}

//决定怎样找书的方法

public static void select(String[] Books) {

Scanner scan = new Scanner(System.in);

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");

try {

int a = scan.nextInt();//如果输入的为字母，则catch

if(a == 1) {

findByName(Books);//调用名字查找方法

}else if(a == 2) {

findByNum(Books);//调用序号查找方法

}else {

System.out.println("命令输入错误！请按提示输入数字命令！");//如果输入的为不符合要求的数字

select(Books);//则跳转回来

}

}catch(Exception e) {

new ErrorMinException();//定义的异常

select(Books);//跳转回来

}

scan.close();

}

//名字查找的方法

public static void findByName(String[] Books) {

System.out.println("请输入图书名称：");

Scanner scan = new Scanner(System.in);

String name = scan.next();

int flag = 0;//判断是否存在

for(String book : Books) {

if(book.equals(name)) {

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

flag = 1;//如果存在，则flag = 1；

}

}

if(flag == 0) {

System.out.println("图书不存在！");//如果flag 任然等于0则不存在

select(Books);//跳转

}

scan.close();

}

public static void findByNum(String[] Books) {

System.out.println("请输入图书序号：");

Scanner scan = new Scanner(System.in);

try {

int num = scan.nextInt();//如果输入的不是int型，则catch

System.out.println("book:" + Books[num]);//如果数组越界，则catch

}catch(Exception e) {

new BookDoesNotExistException();

select(Books);//跳转

}

scan.close();

}

}