使用gzip压缩InputStream [英] Compress an InputStream with gzip

问题描述

我想使用Gzip压缩在java中压缩输入流。

I would like to compress an input stream in java using Gzip compression.

假设我们有一个未压缩的输入流（1GB数据..）。我想要一个来自源的压缩输入流：

Let's say we have an input stream (1GB of data..) not compressed. I want as a result a compressed inputstream from the source :

public InputStream getCompressedStream(InputStream unCompressedStream) {

    // Not working because it's uncompressing the stream, I want the opposite.
    return new GZIPInputStream(unCompressedStream); 

}

推荐答案

压缩数据需要 GZIPOutputStream 。但是，由于您需要像从InputStream那样读取数据，因此需要将OutputStream转换为InputStream。您可以使用getBytes（）来执行此操作：

To compress data you need the GZIPOutputStream. But since you need to read the data back as if from an InputStream you need to convert the OutputStream to an InputStream. You can use getBytes() to do so:

GZIPOutputStream gout = new GZIPOutputStream(out);
//... Code to read from your original uncompressed data and write to out.

//Convert to InputStream.
new ByteArrayInputStream(gout.getBytes());

但是这种方法有一个限制，你需要首先读入所有数据 - 这意味着你有有足够的内存来保存缓冲区。

But this method has the limitation that you need to read in all data first - and that means you have to have enough memory to hold that buffer.

此线程中提到了使用管道的替代方法 - 如何将OutputStream转换为InputStream？

Alternative approaches using Pipes are mentioned in this thread - How to convert OutputStream to InputStream?

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