package com.exception.project;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import java.util.Scanner;

public class BookUtil {

//实例化一个List对象

List<Book> bookList = new ArrayList<Book>();

//查询方法

public void fun() {

BookUtil bu = new BookUtil(); 

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

// List<Book> list = new ArrayList<Book>();

//输出

Scanner scan = new Scanner(System.in);

try {

//输入一个数

int a = scan.nextInt();

boolean flag = false;

//判断是否为1 ，如果为1就进入按名称查找，如果为2就进入按序号查找 ，两者都不是就输出查询不到结果

if(a == 1) {

System.out.println("输入图书名称：");

String name = scan.next();

for (Book book : bookList) {

if(name.equals(book.getName())) {

System.out.println(book.toString());

flag = true;

break;

}

if(flag == false) {

System.out.println("图书名称："+name+"没存在！");

fun();

}

}

}else if(a == 2) {

System.out.println("输入图书序号：");

int id = scan.nextInt();

for (Book book : bookList) {

if(id == book.getId()) {

System.out.println(book.toString());

flag = true;

break;

}

if(flag == false) {

System.out.println("图书名称："+id+"没存在！");

fun();

}

}

}else {

System.out.println("输入数据不合格！");

fun();

}

}catch(Exception e) {

//设置异常提示信息

System.err.println("命令输入错误！请根据提示输入命令");

//如果出现异常就回调

fun();

}

}

//添加方法

public List<Book> addIdName() {

//创建一个book对象，并把book对象添加到list集合中

Book book1 = new Book(1,"高数");;

bookList.add(book1);

//创建一个book对象，并把book对象添加到list集合中

Book book2 = new Book(2,"java程序设计");

bookList.add(book2);

//创建一个book对象，并把book对象添加到list集合中

Book book3 = new Book(3,"数据库结构");

bookList.add(book3);

//创建一个book对象，并把book对象添加到list集合中

Book book4 = new Book(4,"软件工程");

bookList.add(book4);

//返回 list

return bookList;

}

}

package com.exception.project;

import java.util.Objects;

public class Book {

private int id;

private String name;

public Book() {

}

public Book(int id, String name) {

this.id = id;

this.name = name;

}

public int getId() {

return id;

}

public void setId(int id) {

this.id = id;

}

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

@Override

public String toString() {

return "Book : name=" + name + "";

}

@Override

    public boolean equals(Object o) {

        if (this == o) return true;

        if (o == null || getClass() != o.getClass()) return false;

        Book book = (Book) o;

        return Objects.equals(name, book.name) &&

                Objects.equals(id, book.id);

    }

}

package com.exception.project;

import java.util.ArrayList;

import java.util.List;

public class test {

public static void main(String[] args) {

//实例化 BookUtil

BookUtil bu = new BookUtil();

bu.addIdName();

bu.fun();

}

}