马克·阿德勒（Mark Adler）提出了这种方法，这一点值得称赞，这比我最初的回答要好得多。
package stack;import java.io.*;import java.nio.ByteBuffer;import java.nio.channels.FileChannel;import java.util.zip.CRC32;import java.util.zip.Deflater;public class BufferDeflate2 { private static final byte[] GZIP_HEADER = new byte[] { 0x1f, (byte) 0x8b, Deflater.DEFLATED, 0, 0, 0, 0, 0, 0, 0 }; private final CRC32 crc = new CRC32(); private final Deflater deflater = new Deflater(Deflater.BEST_COMPRESSION, true); private final ByteArrayOutputStream buffer = new ByteArrayOutputStream(); private final byte[] transfer = new byte[1000]; private final int flushMode; public BufferDeflate2(boolean syncFlush) { flushMode = syncFlush ? Deflater.SYNC_FLUSH : Deflater.NO_FLUSH; buffer.write(GZIP_HEADER, 0, GZIP_HEADER.length); } public ByteBuffer deflate(ByteBuffer in) { // convert buffer to bytes byte[] inBytes; int off = in.position(); int len = in.remaining(); if( in.hasArray() ) { inBytes = in.array(); } else { off = 0; inBytes = new byte[len]; in.get(inBytes); } // update CRC and deflater crc.update(inBytes, off, len); deflater.setInput(inBytes, off, len); while( !deflater.needsInput() ) { int r = deflater.deflate(transfer, 0, transfer.length, flushMode); buffer.write(transfer, 0, r); } byte[] outBytes = buffer.toByteArray(); buffer.reset(); return ByteBuffer.wrap(outBytes); } public ByteBuffer doFinal() { // finish deflating deflater.finish(); // write all remaining data int r; do { r = deflater.deflate(transfer, 0, transfer.length, Deflater.FULL_FLUSH); buffer.write(transfer, 0, r); } while( r == transfer.length ); // write GZIP trailer writeInt((int) crc.getValue()); writeInt((int) deflater.getBytesRead()); // reset deflater deflater.reset(); // final output byte[] outBytes = buffer.toByteArray(); buffer.reset(); return ByteBuffer.wrap(outBytes); } private void writeInt(int v) { System.out.println("v="+v); buffer.write(v & 0xff); buffer.write((v >> 8) & 0xff); buffer.write((v >> 16) & 0xff); buffer.write((v >> 24) & 0xff); } public static void main(String[] args) throws IOException { File inFile = new File(args[0]); File outFile = new File(args[0]+".test.gz"); FileChannel inChan = (new FileInputStream(inFile)).getChannel(); FileChannel outChan = (new FileOutputStream(outFile)).getChannel(); BufferDeflate2 def = new BufferDeflate2(false); ByteBuffer buf = ByteBuffer.allocate(500); while( true ) { buf.clear(); int r = inChan.read(buf); if( r==-1 ) break; buf.flip(); ByteBuffer compBuf = def.deflate(buf); outChan.write(compBuf); } ByteBuffer compBuf = def.doFinal(); outChan.write(compBuf); inChan.close(); outChan.close(); }}
