之所以选择“流”这个词，是因为它(在现实生活中)与我们使用它时想要传达的意思非常相似。

Start thinking about the analogy to a water stream. You receive a continuous flow of data, just like water continuously flows in a river. You don't necessarily know where the data is coming from, and most often you don't need to; be it from a file, a socket, or any other source, it doesn't (shouldn't) really matter. This is very similar to receiving a stream of water, whereby you don't need to know where it is coming from; be it from a lake, a fountain, or any other source, it doesn't (shouldn't) really matter. source

之所以选择“流”这个词，是因为它(在现实生活中)与我们使用它时想要传达的意思非常相似。

Let's forget about the backing store for a little, and start thinking about the analogy to a water stream. You receive a continuous flow of data, just like water continuously flows in a river. You don't necessarily know where the data is coming from, and most often you don't need to; be it from a file, a socket, or any other source, it doesn't (shouldn't) really matter. This is very similar to receiving a stream of water, whereby you don't need to know where it is coming from; be it from a lake, a fountain, or any other source, it doesn't (shouldn't) really matter.

也就是说，一旦您开始认为您只关心获得所需的数据，而不管数据来自何处，其他人谈论的抽象概念就会变得更加清晰。您开始认为可以包装流，并且您的方法仍然可以完美地工作。例如，你可以这样做:

int ReadInt(StreamReader reader) { return Int32.Parse(reader.ReadLine()); }

// in another method:
Stream fileStream = new FileStream("My Data.dat");
Stream zipStream = new ZipDecompressorStream(fileStream);
Stream decryptedStream = new DecryptionStream(zipStream);
StreamReader reader = new StreamReader(decryptedStream);

int x = ReadInt(reader);

如您所见，在不改变处理逻辑的情况下更改输入源变得非常容易。例如，要从网络套接字而不是文件读取数据:

Stream stream = new NetworkStream(mySocket);
StreamReader reader = new StreamReader(stream);
int x = ReadInt(reader);

尽可能的简单。而且美妙之处还在继续，因为您可以使用任何类型的输入源，只要您可以为它构建一个流“包装器”。你甚至可以这样做:

public class RandomNumbersStreamReader : StreamReader {
    private Random random = new Random();

    public String ReadLine() { return random.Next().ToString(); }
}

// and to call it:
int x = ReadInt(new RandomNumbersStreamReader());

看到了吗?只要您的方法不关心输入源是什么，您就可以以各种方式自定义源。抽象允许您以一种非常优雅的方式将输入与处理逻辑解耦。

请注意，我们自己创建的流没有备份存储，但它仍然完美地满足了我们的目的。

所以，总的来说，流只是一个输入源，隐藏(抽象)了另一个源。只要你不打破抽象，你的代码就会非常灵活。

我长话短说，我刚才漏掉了这个词:

流是通常存储在包含任何类型数据的缓冲区中的队列。

(现在，既然我们都知道队列是什么，就没有必要进一步解释了。)

除了上面提到的东西，还有一种不同类型的流——在函数式编程语言(如Scheme或Haskell)中定义的流——一种可能无限的数据结构，由一些函数按需生成。

A stream is a highly abstracted metaphor and a strict contract. It means that you can manipulate objects in sequence without concern about gaps. That is to say, a stream must have no vacuum or gaps. Objects in it are arranged in sequence one by one continuously. As a result, we don't have to worry about encountering a vacuum abruptly in the midst of processing a stream, or we can't leave a vacuum deliberately when producing a stream. In other words, we don't have to consider the case of a void in processing or producing a stream. There is no way we can come across it or produce it on purpose. If you are constructing a stream, you must not leave any gaps in the stream.

换句话说，如果有一个缺口，它一定不是一个流。当您将序列称为流时，要么您被保证其中没有空白，要么您必须信守您所生成的序列中没有空白的承诺。

回顾一下，想象一条水流。它最大的特点是什么?

连续!

溪流的抽象精神就是关于它的。

把流看作是抽象的数据源(字节、字符等)。它们抽象了具体数据源的实际读写机制，可以是网络套接字、磁盘上的文件或来自web服务器的响应。