Java File Read via ByteBuffer readFull(Reader in)

Description

read Full

License

Apache License

Declaration

public static StringBuilder readFull(Reader in) throws IOException 

Method Source Code

//package com.java2s;
//License from project: Apache License 

import java.io.File;

import java.io.IOException;

import java.io.RandomAccessFile;
import java.io.Reader;

import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;

public class Main {
    public static StringBuilder readFull(Reader in) throws IOException {
        char buf[] = new char[4 * 1024];
        StringBuilder sb = new StringBuilder();

        for (;;) {
            int read = in.read(buf);

            if (read == -1) {
                break;
            }/*  w  w  w.  java 2  s.  c  o m*/

            sb.append(buf, 0, read);
        }

        return sb;
    }

    public static ByteBuffer read(File file, long offset, int length) throws IOException {
        FileChannel chan = channel(file, false);

        ByteBuffer buf = ByteBuffer.allocate(length);
        chan.position(offset);

        while (buf.remaining() > 0) {
            if (chan.read(buf) <= 0) {
                throw new IOException("Failed to read from channel.");
            }
        }

        buf.rewind();
        chan.close();

        return buf;
    }

    public static FileChannel channel(File file, boolean writeable) throws IOException {
        String opts = writeable ? "rw" : "r";
        RandomAccessFile fd = new RandomAccessFile(file, opts);
        FileChannel chan = fd.getChannel();

        return chan;
    }
}

Related

1. ReadFloat(InputStream is)
2. readFromBuffer(byte[] buffer, int start, int end)
3. readFromFile(Path path)
4. readFromFile(String fileName)
5. readFromSocket(SocketChannel channel)
6. readFully(final Reader input, final char[] buffer, final int offset, final int length)
7. readFully(InputStream in)
8. readFullyAndClose(InputStream input)
9. readHeaderArea(InputStream in)