compress byte array - Java File Path IO

Java examples for File Path IO:Byte Array

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Description

compress byte array

Demo Code

/**//  w w  w.  jav  a  2 s  . c  o m
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
//package com.java2s;

import java.util.zip.Deflater;

import java.io.*;

public class Main {
    public static void main(String[] argv) throws Exception {
        byte[] input = new byte[] { 34, 35, 36, 37, 37, 37, 67, 68, 69 };
        System.out.println(java.util.Arrays.toString(compress(input)));
    }

    public static byte[] compress(byte[] input) throws IOException {
        // Create an expandable byte array to hold the compressed data.
        // You cannot use an array that's the same size as the orginal because
        // there is no guarantee that the compressed data will be smaller than
        // the uncompressed data.
        ByteArrayOutputStream bos = new ByteArrayOutputStream(input.length);
        compressToStream(input, bos);
        bos.close();

        // Get the compressed data
        return bos.toByteArray();
    }

    public static void compressToStream(byte[] input,
            ByteArrayOutputStream bos) throws IOException {
        // Create the compressor with highest level of compression
        Deflater compressor = new Deflater();
        compressor.setLevel(Deflater.BEST_COMPRESSION);

        // Give the compressor the data to compress
        compressor.setInput(input);
        compressor.finish();

        // Write the compressed data to the stream
        byte[] buf = new byte[1024];
        while (!compressor.finished()) {
            int count = compressor.deflate(buf);
            bos.write(buf, 0, count);
        }
    }

    public static byte[] toByteArray(int i) {
        byte[] bytes = new byte[4];
        bytes[0] = (byte) ((i >>> 24) & 0xFF);
        bytes[1] = (byte) ((i >>> 16) & 0xFF);
        bytes[2] = (byte) ((i >>> 8) & 0xFF);
        bytes[3] = (byte) (i & 0xFF);
        return bytes;
    }
}

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