CODEWITHSUNDEEP
javaioinputstreamoutputstream
Larry Lu
Larry Lu

Reputation: 1661

How to connect a input stream to a output stream in Java?

Having a InputStream and a OutputStream.
I want to connect them.

What I want to do is reading data from InputStream.
And then output the same data by using OutputStream.
This is my code. 

byte[] b = new byte[8192];
while((len = in.read(b, 0, 8192)) > 0){
    out.write(b, 0, len);
}

Is there any method to connect them?
Or is there any way to input and output data without buffer?

Upvotes: 0

Views: 2779

Answers (3)

andrucz
andrucz

Reputation: 2021

Guava and Apache Commons have copy methods:

ByteStreams.copy(input, output);

IOUtils.copy(input ,output);

They don't "connect" them directly. To achieve what I am assuming you want, create an InputStream decorator class that writes to an OutputStream everything that is read.

Upvotes: 1

lance-java
lance-java

Reputation: 27958

You could use a NIO channel/buffer

try (FileChannel in = new FileInputStream(inFile).getChannel();
     FileChannel out = new FileOutputStream(outFile).getChannel()) 
{
    ByteBuffer buff = ByteBuffer.allocate(8192);

    int len;
    while ((len = in.read(buff)) > 0) { 
        buff.flip();
        out.write(buff);
        buff.clear();
    }
}

Upvotes: -1

Peter Lawrey
Peter Lawrey

Reputation: 533432

Both input and output streams are a passive objects, so there is no way to connect them without creating a Thread to copy the data from one to another.

Note: NIO has a transferTo method though it does much the same, just more efficiently.

You don't have to use a buffer but it likely to be very slow without one.

Upvotes: 1

Related Questions