Scala图书管理系统

项目创建并实现基础UI

package org.app

import scala.io.StdIn

object Main {
  def main(args: Array[String]): Unit = {

    var running = true
    while (running) {
      println("欢迎来到我的图书管理系统，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
        case "2" => println("查询图书")
        case "3" => println("登录")
        //TODO 登录之后，应该要展示不同的UI
        case "4" =>
          running = false
          println("感谢您的使用，下次再见")
        case _ => println("无效的选择")
      }
    }
  }
}

经典的三层结构

改造代码实现UI层

LibrarayPresentation

package org.app
package ui

import org.app.service.BookService

import scala.io.StdIn

class LibrarayPresentation {
 //显示游客的菜单
  private val BookService=new BookService()
  def showVisitorMenu(): Unit = {
    var running = true
    while (running) {
      println("欢迎来到我的图书管理系统，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
        //调用业务逻辑层的方法
        val results=BookService.searchBook("")
        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")
        //TODO 登录之后，应该要展示不同的UI
        case "4" =>
          running = false
          println("感谢您的使用，下次再见")
        case _ => println("无效的选择")
      }
    }
  }

  //显示管理员的菜单
  //显示登录用户的菜单
  def showMenu(): Unit = {
    showVisitorMenu()
  }
}

BookService

package org.app
package service

import models.BookModel

import org.app.dao.BookDAO
import scala.collection.mutable.ListBuffer
class BookService {
  private val bookDAO = new BookDAO()
  //查询所有的图书
//  def searchBook(query:String):图书列表List=(book对象)
  def searchBook(query:String):ListBuffer[BookModel]={
  //从文本文件中读取基本信息，并保存在列表
 bookDAO.loadBooks()
  }

}

BookDAO

package org.app
package dao

import models.BookModel
import scala.collection.mutable.ListBuffer

//图书，数据操作层
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()) {
        println(line)
        val Array(id, name, author, available) = line.split(",")
        books += BookModel(id.toInt, name, author, available.toBoolean)
      }
    //关闭连接
    source.close()
    books
  }
}

BookModel

package org.app
package models

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


}

Main 

package org.app

import org.app.ui.LibrarayPresentation

import scala.io.StdIn

object Main {
  def main(args: Array[String]): Unit = {

    val m = new LibrarayPresentation()
    m.showMenu()
  }
}