Java InputStream Copy copyLarge(InputStream input, OutputStream output)

Description

Copy bytes from a large (over 2GB) InputStream to an OutputStream.

License

Apache License

Parameter

Parameter	Description
input	the <code>InputStream</code> to read from
output	the <code>OutputStream</code> to write to

Exception

Parameter	Description
NullPointerException	if the input or output is null
IOException	if an I/O error occurs

Return

the number of bytes copied

Declaration

public static long copyLarge(InputStream input, OutputStream output)
        throws IOException 

Method Source Code

//package com.java2s;
/*//from   www. j a v 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.
 */

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

public class Main {
    private static final int EOF = -1;
    /**
     * The default buffer size ({@value}) to use for
     * {@link #copyLarge(InputStream, OutputStream)}
     * and
     * {@link #copyLarge(Reader, Writer)}
     */
    private static final int DEFAULT_BUFFER_SIZE = 1024 * 4;

    /**
     * Copy bytes from a large (over 2GB) <code>InputStream</code> to an
     * <code>OutputStream</code>.
     * <p>
     * This method buffers the input internally, so there is no need to use a
     * <code>BufferedInputStream</code>.
     * <p>
     * The buffer size is given by {@link #DEFAULT_BUFFER_SIZE}.
     *
     * @param input  the <code>InputStream</code> to read from
     * @param output  the <code>OutputStream</code> to write to
     * @return the number of bytes copied
     * @throws NullPointerException if the input or output is null
     * @throws IOException if an I/O error occurs
     * @since 1.3
     */
    public static long copyLarge(InputStream input, OutputStream output)
            throws IOException {

        byte[] buffer = new byte[DEFAULT_BUFFER_SIZE];
        long count = 0;
        int n = 0;
        while (EOF != (n = input.read(buffer))) {
            output.write(buffer, 0, n);
            count += n;
        }
        return count;
    }

    /**
     * Reads bytes from an input stream.
     * This implementation guarantees that it will read as many bytes
     * as possible before giving up; this may not always be the case for
     * subclasses of {@link InputStream}.
     *
     * @param input where to read input from
     * @param buffer destination
     * @param offset initial offset into buffer
     * @param length length to read, must be &gt;= 0
     * @return actual length read; may be less than requested if EOF was reached
     * @throws IOException if a read error occurs
     * @since 2.2
     */
    public static int read(final InputStream input, final byte[] buffer,
            final int offset, final int length) throws IOException {
        if (length < 0) {
            throw new IllegalArgumentException(
                    "Length must not be negative: " + length);
        }
        int remaining = length;
        while (remaining > 0) {
            final int location = length - remaining;
            final int count = input.read(buffer, offset + location,
                    remaining);
            if (EOF == count) { // EOF
                break;
            }
            remaining -= count;
        }
        return length - remaining;
    }
}

Related

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