Java FileInputStream Read readFile(File file)

Description

read File

License

Apache License

Declaration

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

Method Source Code

//package com.java2s;
/*//from w w w  .ja  v a 2 s. c o m
 * Copyright [2016] [Mannheim University of Applied Sciences]
 * 
 * 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.EOFException;
import java.io.File;
import java.io.FileInputStream;

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

import java.util.Arrays;

public class Main {
    public static byte[] readFile(File file) throws IOException {
        return readStream(new FileInputStream(file));
    }

    public static byte[] readStream(InputStream input) throws IOException {
        return readStream(input, -1, true);
    }

    public static byte[] readStream(InputStream input, int length, boolean readAll) throws IOException {
        byte[] output = {};
        int position = 0;
        if (length == -1)
            length = Integer.MAX_VALUE;
        while (position < length) {
            int bytesToRead;
            if (position >= output.length) { // Only expand when there's no room
                bytesToRead = Math.min(length - position, output.length + 1024);
                if (output.length < position + bytesToRead)
                    output = Arrays.copyOf(output, position + bytesToRead);
            } else
                bytesToRead = output.length - position;
            int bytesRead = input.read(output, position, bytesToRead);
            if (bytesRead < 0) {
                if (!readAll || length == Integer.MAX_VALUE) {
                    if (output.length != position)
                        output = Arrays.copyOf(output, position);
                    break;
                } else
                    throw new EOFException("Detect premature EOF");
            }
            position += bytesRead;
        }
        return output;
    }
}

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