Java I/O-重用InputStream对象 [英] Java I/O - Reuse InputStream Object

问题描述

是否有通过更改其内容重用inputStream的方法? (没有新的声明).

例如，我能够达到非常接近我的要求的水平，但还不够

在下面的代码中，我使用SequenceInputStream，每次我向该序列添加一个新的InputStream.

但是我想通过使用相同的inputStream来做同样的事情(我不在乎InputStream的哪种实现).

我考虑过mark()/reset() API，但是我仍然需要更改要读取的内容.

Is there anyway to reuse an inputStream by changing its content? (Without new statement).

For instance, I was able to something very close to my requirement, but not enough

In the following code I am using a SequenceInputStream, and everytime I am adding a new InputStream to that sequence.

But I would like to do the same thing by using the same inputStream (I don't care which implementation of InputStream).

I thought about mark()/reset() APIs, but i still need to change the content to be read.

避免新创建InputStream的想法是由于性能问题

The idea to avoid new InputStream creations is because of performance issues

     //Input Streams
    List<InputStream> inputStreams = new ArrayList<InputStream>();
    try{
        //First InputStream
        byte[] input = new byte[]{24,8,102,97};
        inputStreams.add(new ByteArrayInputStream(input));

        Enumeration<InputStream> enu = Collections.enumeration(inputStreams);
        SequenceInputStream is = new SequenceInputStream(enu);

        byte [] out = new byte[input.length];
        is.read(out);

        for (byte b : out){
            System.out.println(b);//Will print 24,8,102,97
        }

        //Second InputStream
        input = new byte[]{ 4,66};
        inputStreams.add(new ByteArrayInputStream(input));
        out = new byte[input.length];
        is.read(out);

        for (byte b : out){
            System.out.println(b);//will print 4,66
        }
        is.close();
    }catch (Exception e){//
    }

推荐答案

否，由于输入流是单向的，即只能在单个方向上移动，因此无法重新读取输入的流.

No, You can't restart reading the input stream after it reaches to the end of the stream as it is uni-directional i.e. moves only in single direction.

但是请参考下面的链接，它们可能会有所帮助:

But Refer below links, they may help:

如何将InputStream缓存为多种用途

>使InputStream读取更多内容一次，无论markSupported()

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