读取文件
// 第一步是获取通道。我们从 FileInputStream 获取通道
FileInputStream fin = new FileInputStream( "readandshow.txt" );
FileChannel fc = fin.getChannel();
// 下一步是创建缓冲区
ByteBuffer buffer = ByteBuffer.allocate( 1024 );
// 最后，将数据从通道读到缓冲区中
fc.read( buffer );
写入文件
// 首先从 FileOutputStream 获取一个通道
FileOutputStream fout = new FileOutputStream( "writesomebytes.txt" );
FileChannel fc = fout.getChannel();
// 创建一个缓冲区并在其中放入一些数据 - 在这里，数据将从一个名为 message 的数组中取出
ByteBuffer buffer = ByteBuffer.allocate( 1024 );
for (int i=0; i<message.length; ++i) {
buffer.put( message[i] );
}
buffer.flip();
// 最后一步是写入缓冲区中
fc.write( buffer );
服务端
import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.Iterator;
import java.util.Set;
public class EpollServer {
public static void main(String[] args) {
try {
ServerSocketChannel ssc = ServerSocketChannel.open();
ssc.socket().bind(new InetSocketAddress("127.0.0.1", 8000));
ssc.configureBlocking(false);
Selector selector = Selector.open();
// 注册 channel，并且指定感兴趣的事件是 Accept
ssc.register(selector, SelectionKey.OP_ACCEPT);
ByteBuffer readBuff = ByteBuffer.allocate(1024);
ByteBuffer writeBuff = ByteBuffer.allocate(128);
writeBuff.put("received".getBytes());
writeBuff.flip();
while (true) {
int nReady = selector.select();
Set<SelectionKey> keys = selector.selectedKeys();
Iterator<SelectionKey> it = keys.iterator();
while (it.hasNext()) {
SelectionKey key = it.next();
it.remove();
if (key.isAcceptable()) {
// 创建新的连接，并且把连接注册到selector上，而且，
// 声明这个channel只对读操作感兴趣。
SocketChannel socketChannel = ssc.accept();
socketChannel.configureBlocking(false);
socketChannel.register(selector, SelectionKey.OP_READ);
}
else if (key.isReadable()) {
SocketChannel socketChannel = (SocketChannel) key.channel();
readBuff.clear();
socketChannel.read(readBuff);
readBuff.flip();
System.out.println("received : " + new String(readBuff.array()));
key.interestOps(SelectionKey.OP_WRITE);
}
else if (key.isWritable()) {
writeBuff.rewind();
SocketChannel socketChannel = (SocketChannel) key.channel();
socketChannel.write(writeBuff);
key.interestOps(SelectionKey.OP_READ);
}
}
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
Reference