Java File Read via ByteBuffer readFile(String filename)

Description

read File

License

Open Source License

Declaration

public static String readFile(String filename) throws IOException 

Method Source Code

//package com.java2s;
/*/* www .j a va  2  s  . c  om*/
 * ============================================================================
 * GNU General Public License
 * ============================================================================
 *
 * Copyright (C) 2015 Infinite Automation Software. All rights reserved.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * When signing a commercial license with Infinite Automation Software,
 * the following extension to GPL is made. A special exception to the GPL is
 * included to allow you to distribute a combined work that includes BAcnet4J
 * without being obliged to provide the source code for any proprietary components.
 *
 * See www.infiniteautomation.com for commercial license options.
 * 
 * @author Matthew Lohbihler
 */

import java.io.ByteArrayOutputStream;
import java.io.CharArrayWriter;
import java.io.File;
import java.io.FileReader;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.Reader;
import java.io.StringWriter;
import java.io.Writer;
import java.nio.ByteBuffer;
import java.nio.channels.SocketChannel;

public class Main {
    public static String readFile(String filename) throws IOException {
        return readFile(new File(filename));
    }

    public static String readFile(File file) throws IOException {
        FileReader in = null;
        try {
            in = new FileReader(file);
            StringWriter out = new StringWriter();
            transfer(in, out);
            return out.toString();
        } finally {
            if (in != null)
                in.close();
        }
    }

    public static void transfer(InputStream in, OutputStream out)
            throws IOException {
        transfer(in, out, -1);
    }

    public static void transfer(InputStream in, OutputStream out, long limit)
            throws IOException {
        byte[] buf = new byte[1024];
        int readcount;
        long total = 0;
        while ((readcount = in.read(buf)) != -1) {
            if (limit != -1) {
                if (total + readcount > limit)
                    readcount = (int) (limit - total);
            }

            if (readcount > 0)
                out.write(buf, 0, readcount);

            total += readcount;
            if (limit != -1 && total >= limit)
                break;
        }
        out.flush();
    }

    public static void transfer(InputStream in, SocketChannel out)
            throws IOException {
        byte[] buf = new byte[1024];
        ByteBuffer bbuf = ByteBuffer.allocate(1024);
        int len;
        while ((len = in.read(buf)) != -1) {
            bbuf.put(buf, 0, len);
            bbuf.flip();
            while (bbuf.remaining() > 0)
                out.write(bbuf);
            bbuf.clear();
        }
    }

    public static void transfer(Reader reader, Writer writer)
            throws IOException {
        transfer(reader, writer, -1);
    }

    public static void transfer(Reader reader, Writer writer, long limit)
            throws IOException {
        char[] buf = new char[1024];
        int readcount;
        long total = 0;
        while ((readcount = reader.read(buf)) != -1) {
            if (limit != -1) {
                if (total + readcount > limit)
                    readcount = (int) (limit - total);
            }

            if (readcount > 0)
                writer.write(buf, 0, readcount);

            total += readcount;
            if (limit != -1 && total >= limit)
                break;
        }
        writer.flush();
    }

    public static byte[] read(InputStream in) throws IOException {
        ByteArrayOutputStream out = new ByteArrayOutputStream(
                in.available());
        transfer(in, out);
        return out.toByteArray();
    }

    public static char[] read(Reader reader) throws IOException {
        CharArrayWriter writer = new CharArrayWriter();
        transfer(reader, writer);
        return writer.toCharArray();
    }
}

Related

1. readFile(File file)
2. readFile(File file)
3. readFile(File file)
4. readFile(java.io.File file)
5. readFile(String filename)
6. readFile(String fileName)
7. readFile(String filename)
8. readFile(String filePath)
9. readFile(String name)