1，创建dao，models，service，ui等软件包

2，在各软件包下创建scala类

软件包dao里的代码

package org.app
package dao

import models.BookModel

import scala.collection.mutable.ListBuffer

//图书，数据操作
class BookDAO {
  //加载图书，从文件中读入
  def loadBooks(): ListBuffer[BookModel] = {
    val books = new ListBuffer[BookModel]()
    val source =scala.io.Source.fromFile("books.txt")
    for (line <- source.getLines()){
      val Array(id, name, author,available) = line.split(",")
      //
       books += BookModel(id.toInt, name, author, available.toBoolean)
    }
    //关闭连接
    source.close()
    books
  }
}

软件包models里的代码

package org.app
package models

//图书类
//id,书名，作者，available:是否外借
case class BookModel(id:Int,name:String,author:String,available:Boolean) {


}

软件包service代码

package org.app
package service

import org.app.dao.BookDAO
import org.app.models.BookModel

import scala.collection.mutable.ListBuffer



//图书业务逻辑层
class BookService {
    private val bookDAO = new BookDAO()
  //查询所有图书
//  def searchBooks(query: String): List[Book对象] = {
def searchBooks(query: String): ListBuffer[BookModel] = {
  //从文本文件中读取书本信息，并保存列表中，返回
    bookDAO.loadBooks()

}
}

ui软件包里的代码

package org.app
package UI

import org.app.service.BookService

import scala.io.StdIn

class Library {
  private val BookService = new BookService()


  def showMenu(): Unit = {
    showVisitorMenu()
  }

  def showVisitorMenu(): Unit = {
    var running = true
    while (running) {
      println("欢迎来到我的图书馆系统，请选择")
      println("1.查看所有图书")
      println("2.查询图书")
      println("3.登录")
      println("4.离开")

      //获取用户的操作
      val choice = StdIn.readLine().trim
      choice match {
        case "1" =>
          println("查看所有图书")
          //TODO 查看所有图书
         val results = BookService.searchBooks("")
          if (results.nonEmpty){
            results.foreach(println)
          }else{
            println("没有找到图书")
          }
        case "2" => println("查询图书")
        case "3" => println("登录")
        case "4" =>
          running = false
          println("感谢你的使用,下次再见")
        case _ => println("无效的选择")
      }
    }
  }
}

src目录下的代码

package org.app

import org.app.UI.Library

import scala.io.StdIn

object Main {
  def main(args: Array[String]): Unit = {
    val m = new Library()
    m.showMenu()


  }

}

在项目下新建文件books.txt复制一些书籍作者，书籍名称，是否外借。

最后在软件包ui里的scala中调用代码。