Java File to Byte Array getBytesFromFile(File file)

Description

Reads all bytes from the given file and returns a byte array.

License

Apache License

Parameter

Parameter	Description
file	the file to read

Exception

Parameter	Description
IOException	if the file cannot be read

Return

the data read from the file

Declaration

public static byte[] getBytesFromFile(File file) throws IOException 

Method Source Code

//package com.java2s;
/*******************************************************************************
 * Copyright 2006 - 2012 Vienna University of Technology,
 * Department of Software Technology and Interactive Systems, IFS
 * /*w w w . j ava2s .com*/
 * Licensed 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.BufferedInputStream;

import java.io.File;
import java.io.FileInputStream;

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

public class Main {
    /**
     * Reads all bytes from the given file and returns a byte array.
     * 
     * @param file
     *            the file to read
     * @return the data read from the file
     * @throws IOException
     *             if the file cannot be read
     */
    public static byte[] getBytesFromFile(File file) throws IOException {
        if (file == null) {
            return null;
        }
        InputStream is = new BufferedInputStream(new FileInputStream(file));
        byte[] bytes;
        try {

            // Get the size of the file
            long length = file.length();

            if (length > Integer.MAX_VALUE) {
                throw new IOException("File is too large " + file.getName());
            }

            // Create the byte array to hold the data
            bytes = new byte[(int) length];

            // Read in the bytes
            int offset = 0;
            int numRead = 0;
            while (offset < bytes.length && (numRead = is.read(bytes, offset, bytes.length - offset)) >= 0) {
                offset += numRead;
            }

            // Ensure all the bytes have been read in
            if (offset < bytes.length) {
                throw new IOException("Could not completely read file " + file.getName());
            }

        } finally {
            // Close the input stream and return bytes
            is.close();
        }
        return bytes;
    }
}

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