Question

对于tcp绑定服务器套接字，我们按如下方式读取它：

   val BufSize = (Math.pow(2, 20) - 1).toInt  // Far more than necessary
    val is = new BufferedInputStream(socket.getInputStream)
    val os = new BufferedOutputStream(socket.getOutputStream)
    val buf = new Array[Byte](BufSize)
    val nread = is.read(buf)
    println(s"Nread=$nread")

我们看到nread的值低于2K，即使对于长度达100K的缓冲区也是如此。当发送的实际数据是＆lt;大约2K然后传输成功：但是自然对于任何更大的我们都有EOF：

[WARNING]
java.io.EOFException
    at java.io.ObjectInputStream$BlockDataInputStream.readFully(ObjectInputStream.java:3063)
    at java.io.ObjectInputStream.readArray(ObjectInputStream.java:1914)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1529)
    at java.io.ObjectInputStream.readObject(ObjectInputStream.java:422)
    at org.openchai.tcp.util.TcpCommon$.deserializeObject(TcpCommon.scala:43)
    at org.openchai.tcp.util.TcpCommon$.deserializeStream(TcpCommon.scala:32)
    at org.openchai.tcp.util.TcpCommon$.unpack(TcpCommon.scala:54)
    at org.openchai.tcp.rpc.TcpServer$$anon$2.run(TcpServer.scala:112)

鉴于BufSize是1兆字节为什么我们最终会遇到问题？

注意：如果将read放入循环中，那么在第二次迭代时它就会挂起。这是尝试过的代码：

   var nread = -1
    var totalRead = 0
    var off = 0
    do {
      if (!msgPrinted) {
        debug("Listening for messages.."); msgPrinted = true
      }
      do {
        println("about to read..")
        nread = is.read(buf,off, buf.length-off)
        totalRead += nread
        println(s"read $nread bytes (totalRead=$totalRead)")
      } while (nread > 0)
      println(s"Final off=$off bytes=$totalRead")

为什么这个套接字读取器代码最终会出现缓冲区截断？

0 个答案: