Java FileInputStream Read readFile(File file)

Description

Reads the given file, translating IOException to a RuntimeException of some sort.

License

Apache License

Parameter

Parameter	Description
file	non-null; the file to read

Exception

Parameter	Description
IOException	an exception

Return

non-null; contents of the file

Declaration

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

Method Source Code

//package com.java2s;
/*//  ww  w.ja  va  2s .c o m
 * Copyright (C) 2007 The Android Open Source Project
 *
 * 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.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;

public class Main {
    /**
     * Reads the named file, translating {@link IOException} to a
     * {@link RuntimeException} of some sort.
     *
     * @param fileName {@code non-null;} name of the file to read
     * @return {@code non-null;} contents of the file
     */
    public static byte[] readFile(String fileName) throws IOException {
        File file = new File(fileName);
        return readFile(file);
    }

    /**
     * Reads the given file, translating {@link IOException} to a
     * {@link RuntimeException} of some sort.
     *
     * @param file {@code non-null;} the file to read
     * @return {@code non-null;} contents of the file
     * @throws IOException
     */
    public static byte[] readFile(File file) throws IOException {
        if (!file.exists()) {
            throw new RuntimeException(file + ": file not found");
        }

        if (!file.isFile()) {
            throw new RuntimeException(file + ": not a file");
        }

        if (!file.canRead()) {
            throw new RuntimeException(file + ": file not readable");
        }

        long longLength = file.length();
        int length = (int) longLength;
        if (length != longLength) {
            throw new RuntimeException(file + ": file too long");
        }

        ByteArrayOutputStream baos = new ByteArrayOutputStream(length);

        InputStream in = null;
        try {
            in = new BufferedInputStream(new FileInputStream(file));
            byte[] buffer = new byte[8192];
            int bytesRead = 0;
            while ((bytesRead = in.read(buffer)) > 0) {
                baos.write(buffer, 0, bytesRead);
            }
        } finally {
            if (in != null) {
                try {
                    in.close();
                } catch (Exception e) {
                    // ignored.
                }
            }
        }

        return baos.toByteArray();
    }
}

Related

1. readFile(File f, int iChunkSize)
2. readFile(File file)
3. readFile(File file)
4. readFile(File file)
5. readFile(File file)
6. readFile(File file)
7. readFile(File file)
8. readFile(File file)
9. readFile(File file)