Scala项目(图书管理系统)

5、dao

BookDAO

package org.app
package dao

import org.app.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()){
      val Array(id,name,author,available) = line.split(",")
      // 实例化一本书，保存到List
      books += BookModel(id.toInt,name,author,available.toBoolean)
    }
    // 关闭连接
    source.close()
    books
  }

  // 保存图书。将图书写入文件
  def saveBooks(books: ListBuffer[BookModel]): Unit = {
    val writer = new java.io.PrintWriter(new java.io.File("books.txt"))
    for(book <- books){
      writer.println(book.id + "," + book.name + "," + book.author + "," + book.available)
    }
    writer.close()
  }
}

BorrowRecordDAO

package org.app
package dao

import org.app.models.BorrowRecordModel

import scala.collection.mutable.ListBuffer
import scala.io.Source

class BorrowRecordDAO {
  // 读出借阅记录
  def loadBorrowRecords(): ListBuffer[BorrowRecordModel] = {
    val borrowRecords = ListBuffer[BorrowRecordModel]()
    val lines = Source.fromFile("borrow_records.txt")
    for(line <- lines.getLines()){
      val Array(userName,bookID,bookName,borrowDate,returnDate) = line.split(",")
      borrowRecords += BorrowRecordModel(userName,bookID.toInt,bookName,borrowDate,Some(returnDate))
    }
    borrowRecords
  }

  // 写入借阅记录
  def saveBorrowRecords(records: ListBuffer[BorrowRecordModel]): Unit = {
    val writer = new java.io.PrintWriter("borrow_records.txt")
    for(record <- records){
      writer.println(record.userName+","+record.bookID+","+record.bookName+","+record.borrowDate+","+record.returnDate.getOrElse(""))
    }
    writer.close()
  }
}

UserDAO

package org.app
package dao

import org.app.models.UserModel

import scala.collection.mutable.ListBuffer

class UserDAO {
  // 加载所有的用户
  def loadUsers(): ListBuffer[UserModel] = {
    val users = new ListBuffer[UserModel]()
    val source = scala.io.Source.fromFile("users.txt")
    for(line <- source.getLines()){
      val Array(username, password, role) = line.split(",")
      // 实例化一个用户，保存到List
      users += UserModel(username, password, role)
    }
    // 关闭连接
    source.close()
    users
  }
}

原文地址：https://blog.csdn.net/2401_84653595/article/details/144656780

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