2-scala file operation--automatically closes open resources, reads properties file

Brief introduction

Automatically close open resources using Scala's loan pattern

Read the Properties file

Dependent jar

When you use the Scala_arm library to automatically close resource files, you need to introduce the following dependencies:

<dependency><groupid>com.jsuereth</groupid><artifactid>scala-arm_${ Scala.binary.version}</artifactid><version>1.4</version></dependency>

Sample code

import java.io.inputstreamimport java.util.propertiesimport  Scala.collection.javaconversions.propertiesasscalamapimport resource.managedimport test. Control._object control {  def using[a <: { def close ():  UNIT&NBSP;},&NBSP;B] (resource: a) (f: a => b):  b =    try  {      f (Resource)     } finally {       if  (resource != null)          resource.close ()     }}object FileOperator extends App {   val prop = new properties ()   //read the configuration file under Classpath   // Read the properties file   //use Scala_arm to automatically close open File Resources   for  (    source  <- managed (FileOperator.getClass.getClassLoader.getResourceAsStream ("Db.prOperties "))   )  {    printprop (source)   }  // Use the using to automatically close Open file resource   using (FileOperator.getClass.getClassLoader.getResourceAsStream ("Db.properties"))  { source =>    {      printprop (source)     }  }  //using an absolute path to read files   val res =  ReadTextFile ("D:/scalawork/scala-learn/src/main/resources/db.properties")   res match {     case some (lines)  => lines.foreach (println)      Case none        => println ("Couldn ' t read file ")   }  //handles the exception and returns Option  def readtextfile (filename: string):  Option[list[string]] = {    try {      val  lines = using (IO. Source.fromfile(filename))  { source =>         (for  (line <-  Source.getlines)  yield line) .tolist      }       some (lines)     } catch {      case  e: exception => none    }  }  // Load properties and convert to HashMap, read its contents   def printprop (Source: inputstream)  = {     prop.load (source)     println (Prop.getproperty ("Jdbc.idlemaxage"))      prop.foreach (Ele => {      println (S "${ele._1}  => ${ele._2} ")     })   }}

2-scala file operation--automatically closes open resources, reads properties file