NIO-01

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.net.InetSocketAddress;
import java.net.ServerSocket;
import java.nio.ByteBuffer;
import java.nio.IntBuffer;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;
import java.nio.channels.FileChannel.MapMode;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.nio.file.OpenOption;
import java.nio.file.Path;
import java.nio.file.StandardOpenOption;
import java.util.Arrays;

public class Demo01 {

    public static void main(String[] args) {

        testServerSOcketChannel();
    }

    public static void testServerSOcketChannel() {

        try {
            // 1. eg: 创建 ServerSocketChannel 实例
            ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();
            // System.out.println(serverSocketChannel.getClass());//sun.nio.ch.ServerSocketChannelImpl
            // 2. eg: 要绑定ip和端口
            InetSocketAddress address = new InetSocketAddress(7777);
            // 3. eg: 通过 ServerSocketChannel 创建 ServerSocket
            ServerSocket serverSocket = serverSocketChannel.socket();
            // 4. eg: 绑定 ServerSocket到指定的ip和端口
            serverSocket.bind(address);

            // 5. eg: 创建 ByteBuffer 数组
            ByteBuffer[] bufs = { ByteBuffer.allocate(5), ByteBuffer.allocate(3) };

            // 6. eg: 创建 SocketChannel 实例
            SocketChannel socketChannel = serverSocketChannel.accept();

            int messageLength = 8;

            while (true) {
                int byteRead = 0;
                while (byteRead < messageLength) {
                    // socketChannel 可以将数据读入到 ByteBuffer 数组里面
                    long read = socketChannel.read(bufs);
                    byteRead += read;
                    System.out.println("byteRead:" + byteRead);

                    // 1. 遍历输出 ByteBuffer 数组
                    Arrays.asList(bufs).stream().map(buf -> "position:" + buf.position() + ",limit:" + buf.limit())
                            .forEach(System.out::println);

                }
                // 2. 将所有的ByteBuffer 元素 flip
                Arrays.asList(bufs).forEach(ByteBuffer::flip);
                System.out.println("flip............");

                //3. 读出ByteBuffer的数据
                int byteWrite = 0;
                while (byteWrite < messageLength) {

                    long write = socketChannel.write(bufs);
                    byteWrite += write;
                    System.out.println("byteWrite:" + byteWrite);
                }

                // 4. 将所有的 ByteBuffer 元素 复位
                Arrays.asList(bufs).forEach(ByteBuffer::clear);
                Arrays.asList(bufs).stream().map(buf -> "position:" + buf.position() + ",limit:" + buf.limit())
                        .forEach(System.out::println);
                Arrays.asList(bufs).stream().map(buf -> new String(buf.array(),0,buf.limit()))
                .forEach(System.out::println);
            }

        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }

    /**
     * 1. 测试内存映射
     */
    public static void testMapByteBuffer() {

        try {
            RandomAccessFile randomAccessFile = new RandomAccessFile("1.txt", "rw");
            FileChannel channel = randomAccessFile.getChannel();
            MappedByteBuffer mappedByteBuffer = channel.map(FileChannel.MapMode.READ_WRITE, 0, 5);

            mappedByteBuffer.put(0, (byte) 'a');
            mappedByteBuffer.put(1, (byte) 'b');
            mappedByteBuffer.put(2, (byte) 'c');

            randomAccessFile.close();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }

    /**
     * 1. 测试只读ByteBuffer
     */
    public static void testReadOnlyBuffer() {

        ByteBuffer buffer = ByteBuffer.allocate(5);
        System.out.println(buffer.getClass());// HeapByteBuffer
        ByteBuffer readOnlyBuffer = buffer.asReadOnlyBuffer();// 
        System.out.println(buffer.getClass());
        System.out.println(readOnlyBuffer.getClass());// HeapByteBufferR
        readOnlyBuffer.put((byte) 1);// ReadOnlyBufferException
    }

    public static void testCopyFile02() {
        try {
            FileInputStream fis = new FileInputStream("1.avi");
            FileChannel channel01 = fis.getChannel();

            FileOutputStream fos = new FileOutputStream("2.avi");
            FileChannel channel02 = fos.getChannel();

            // channel01.transferFrom(src, position, count);
            channel02.transferFrom(channel01, 0, channel01.size());

            fis.close();
            fos.close();

        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    public static void testCopyFile01() {
        try {
            FileInputStream fis = new FileInputStream("a.txt");
            FileChannel channel01 = fis.getChannel();

            FileOutputStream fos = new FileOutputStream("2.txt");
            FileChannel channel02 = fos.getChannel();

            ByteBuffer buffer = ByteBuffer.allocate(5);

            while (true) {

                // buffer 复位
                buffer.clear();

                int read = channel01.read(buffer);
                if (read == -1) {
                    break;
                }

                buffer.flip();
                channel02.write(buffer);

                // (read = channel01.read(buffer)) != -1
            }

            fis.close();
            fos.close();

        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    public static void testChannelRead() {

        try {
            FileInputStream fis = new FileInputStream("a.txt");
            FileChannel channel = fis.getChannel();

            ByteBuffer dst = ByteBuffer.allocate(1024);
            int read = channel.read(dst);

            System.out.println(new String(dst.array(), 0, dst.position()));

            fis.close();

        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }

    public static void testChannelWrite() {

        try {
            FileOutputStream fos = new FileOutputStream("a.txt");
            FileChannel channel = fos.getChannel();
            ByteBuffer buffer = ByteBuffer.allocate("aaabbbccc".getBytes().length);
            buffer.put("aaabbbccc".getBytes());
            buffer.flip();
            channel.write(buffer);

            fos.close();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    /**
     * 01.
     */
    public static void testBuffer() {
        /**
         * 1. IntBuffer: 
         * 
         */
        IntBuffer buffer = IntBuffer.allocate(5);

        buffer.put(1);
        buffer.put(2);
        buffer.put(3);
        // buffer.put(4);
        // buffer.put(5);
        System.out.println("1: position:" + buffer.position());// 3
        System.out.println("1: limit:" + buffer.limit());// 5

        buffer.flip();
        System.out.println("1: position:" + buffer.position());// 0
        System.out.println("1: limit:" + buffer.limit());// 3

        while (buffer.hasRemaining()) {
            int i = buffer.get();
            System.out.println(i);
        }
    }
}