Idiomatic way to convert an InputStream to a String in Scala

问题

I have a handy function that I've used in Java for converting an InputStream to a String. Here is a direct translation to Scala:

  def inputStreamToString(is: InputStream) = {
    val rd: BufferedReader = new BufferedReader(new InputStreamReader(is, "UTF-8")) 
    val builder = new StringBuilder()    
    try {
      var line = rd.readLine 
      while (line != null) { 
        builder.append(line + "\n")
        line = rd.readLine
      }
    } finally {
      rd.close
    }
    builder.toString
  }

Is there an idiomatic way to do this in scala?

回答1:

For Scala >= 2.11

scala.io.Source.fromInputStream(is).mkString

For Scala < 2.11:

scala.io.Source.fromInputStream(is).getLines().mkString("\n")

does pretty much the same thing. Not sure why you want to get lines and then glue them all back together, though. If you can assume the stream's nonblocking, you could just use .available, read the whole thing into a byte array, and create a string from that directly.

回答2:

Source.fromInputStream(is).mkString("") will also do the deed.....

回答3:

Faster way to do this:

    private def inputStreamToString(is: InputStream) = {
        val inputStreamReader = new InputStreamReader(is)
        val bufferedReader = new BufferedReader(inputStreamReader)
        Iterator continually bufferedReader.readLine takeWhile (_ != null) mkString
    }

来源：https://stackoverflow.com/questions/5221524/idiomatic-way-to-convert-an-inputstream-to-a-string-in-scala