Scala 输入输出

• 从屏幕（控制台）中获取输入

object ScalaIn {
    def main(args: Array[String]): Unit = {
        // 标准化屏幕输入
        val age : Int = scala.io.StdIn.readInt()
        println(age)
}
}

• 从文件中获取输入

object ScalaIn {
def main(args: Array[String]): Unit = {
    // 请注意文件路径的位置
        scala.io.Source.fromFile("input/user.json").foreach(
            line => {
                print(line)
            }
        )
scala.io.Source.fromFile("input/user.json").getLines()
}
}

Scala进行文件写操作，用的都是 java中的I/O类

object ScalaOut {
    def main(args: Array[String]): Unit = {
	      val writer = new PrintWriter(new File("output/test.txt" ))
	      writer.write("Hello Scala")
	      writer.close()
	}
}

Scala进行网络数据交互时，采用的也依然是 java中的I/O类

object TestServer {
    def main(args: Array[String]): Unit = {
        val server = new ServerSocket(9999)
        while ( true ) {
            val socket: Socket = server.accept()
            val reader = new BufferedReader(
                new InputStreamReader(
                    socket.getInputStream,
                    "UTF-8"
                )
            )
            var s : String = ""
            var flg = true
            while ( flg  ) {
                s = reader.readLine()
                if ( s != null ) {
                    println(s)
                } else {
                    flg = false
                }
            }
        }
    }
}

...

object TestClient {
    def main(args: Array[String]): Unit = {
        val client = new Socket("localhost", 9999)
        val out = new PrintWriter(
            new OutputStreamWriter(
                client.getOutputStream,
                "UTF-8"
            )
        )
        out.print("hello Scala")
        out.flush()
        out.close()
        client.close()
    }
}