Java作业 -- 借书系统（亲测，已通过！）

/**
 * Created by yuyong on 2017/2/15.
 */
public class Book {
    public String bookName;
    public int bookNum;

    public Book(int bookNum, String bookName) {
        this.bookNum = bookNum;
        this.bookName = bookName;
    }
}

/**
 * Created by yuyong on 2017/2/15.
 */
public class NoExistException extends Exception {

    public NoExistException(String message) {
        super(message);
    }
}

import java.util.*;

/**
 * Created by yuyong on 2017/2/15.
 */
public class FindBooks {
    Book[] book = {new Book(1, "语文"), new Book(2, "数学"), new Book(3, "外语"), new Book(4, "Java编程")};

    public List<Book> listbooks;

    public FindBooks() {
        this.listbooks = new ArrayList<Book>();
    }

    public void listBooksAdd() {
        listbooks.addAll(Arrays.asList(book));
    }

    public void printBooks() {
        System.out.println("---------- 欢迎使用借书系统 ----------");
        System.out.println("图书列表展示如下：");
        System.out.println("序号" + "\t" + "书名");

        for (Book bk : listbooks) {
            System.out.println(bk.bookNum + "\t" + bk.bookName);
        }
    }

    private Scanner input = new Scanner(System.in);

    public static void main(String[] args) {
        FindBooks fb = new FindBooks();
        fb.listBooksAdd();
        fb.printBooks();

        System.out.println();
        while (true) {
            System.out.println("请您输入命令：1.按名称查找书籍\t2.按序号查找书籍");
            switch (fb.scanf()) {
                case 1:
                    try {
                        System.out.println("书籍：" + fb.findByName());
                        break;
                    } catch (Exception e) {
                        System.out.println(e.getMessage());
                        continue;
                    }
                case 2:
                    try {
                        System.out.println("书籍：" + fb.findById());
                        break;
                    } catch (Exception e) {
                        System.out.println(e.getMessage());
                        continue;
                    }
                default:
                    System.out.println("错误的命令，请按提示输入，重新输入");
                    continue;
            }
            break;
        }
        fb.input.close();
    }

    public String findById() throws NoExistException {
        System.out.println("请输入书籍的序号：");
        int in = input.nextInt();
        for (int i = 0; i < book.length; i++) {
            if (in == (i + 1))
                return book[i].bookName;
        }
        throw new NoExistException("序号越界，此书籍不存在！！！");
    }

    public String findByName() throws NoExistException {
        System.out.println("请输入书籍的名称：");
        String name = input.next();
        for (Book bk : listbooks) {
            if (name.equals(bk.bookName)) {
                return bk.bookName;
            }
        }
        throw new NoExistException("名称错误，此书籍不存在！！！");
    }

    public int scanf() {
        try {
            int in = input.nextInt();
            return in;
        } catch (Exception e) {
            input = new Scanner(System.in);
            return -1;
        }
    }
}

---------- 欢迎使用借书系统 ----------
图书列表展示如下：
序号 书名
1 语文
2 数学
3 外语
4 Java编程

请您输入命令：1.按名称查找书籍 2.按序号查找书籍
2
请输入书籍的序号：
5
序号越界，此书籍不存在！！！
请您输入命令：1.按名称查找书籍 2.按序号查找书籍
2
请输入书籍的序号：
4
书籍：Java编程