／／主函数
package test;

import java.util.Scanner;

public class main {

    private static int order;
    private static Scanner input;

    public static void main (String[] args) {
        input = new Scanner(System.in);
        String[] books = { "数据结构", "高数", "大学英语", "离散数学" };
        boolean flag = true;
        while (flag) {

            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");

            order = input.nextInt();

            try {
                if (order == 1) {
                    System.out.println("输入图书名称：");
                    String name = input.next();
                    flag=bookSearch.nameSearch(books, name);
                }

                else if (order == 2) {
                    System.out.println("输入图书序号：");
                    int id = input.nextInt();
                    bookSearch.idSearch(books, id);
                }

                else {
                    System.out.println("命令错误输入！请根据提示输入数字命令！");
                }
            }

            catch (Exception e) {
                System.out.println(e.getMessage());
            }

        }
    }
}

／／功能实现
package test;

public class bookSearch extends Exception {

    public class java {

    }

    public static boolean idSearch(String[] books, int id) throws Exception {
        boolean flag = true;
        if (id > books.length || id < 0)
            throw new Exception("图书不存在");

        else {
            System.out.println("book:" + books[id - 1]);
            flag = false;
        }
        return flag;
    }

    public static boolean nameSearch(String[] books, String name) throws Exception {
        boolean flag = true;
        for (int i = 0; i < books.length; i++) {
            if (name.equals(books[i])) {
                System.out.println("book:" + name);
                flag = false;
                break;
            }
        }
        if (flag)
            throw new Exception("图书不存在");
        return flag;
    }

}