public class MyServer {
  private static ExecutorService executorService = Executors.newCachedThreadPool();  //创建一个线程池
  private static class HandleMsg implements Runnable{   //一旦有新的客户端请求，创建这个线程进行处理
  Socket client;   //创建一个客户端
  public HandleMsg(Socket client){  //构造传参绑定
   this.client = client;
  }
  @Override
  public void run() {
   BufferedReader bufferedReader = null;  //创建字符缓存输入流
   PrintWriter printWriter = null;   //创建字符写入流
   try {
    bufferedReader = new BufferedReader(new InputStreamReader(client.getInputStream()));  //获取客户端的输入流
    printWriter = new PrintWriter(client.getOutputStream(),true);   //获取客户端的输出流，true是随时刷新
    String inputLine = null;
    long a = System.currentTimeMillis();
    while ((inputLine = bufferedReader.readLine())!=null){
     printWriter.println(inputLine);
    }
    long b = System.currentTimeMillis();
    System.out.println("此线程花费了："+(b-a)+"秒！");
   } catch (IOException e) {
    e.printStackTrace();
   }finally {
    try {
     bufferedReader.close();
     printWriter.close();
     client.close();
    } catch (IOException e) {
     e.printStackTrace();
    }
   }
  }
 }
 public static void main(String[] args) throws IOException {   //服务端的主线程是用来循环监听客户端请求
  ServerSocket server = new ServerSocket(8686);  //创建一个服务端且端口为8686
  Socket client = null;
  while (true){   //循环监听
   client = server.accept();  //服务端监听到一个客户端请求
   System.out.println(client.getRemoteSocketAddress()+"地址的客户端连接成功!");
   executorService.submit(new HandleMsg(client));  //将该客户端请求通过线程池放入HandlMsg线程中进行处理
  }
 }
}

public class MyClient {
 public static void main(String[] args) throws IOException {
  Socket client = null;
  PrintWriter printWriter = null;
  BufferedReader bufferedReader = null;
  try {
   client = new Socket();
   client.connect(new InetSocketAddress("localhost",8686));
   printWriter = new PrintWriter(client.getOutputStream(),true);
   printWriter.println("hello");
   printWriter.flush();
   bufferedReader = new BufferedReader(new InputStreamReader(client.getInputStream()));   //读取服务器返回的信息并进行输出
   System.out.println("来自服务器的信息是："+bufferedReader.readLine());
  } catch (IOException e) {
   e.printStackTrace();
  }finally {
   printWriter.close();
   bufferedReader.close();
   client.close();
  }
 }
}

ByteBuffer byteBuffer = ByteBuffer.allocate(1024);

1).数据从Channel到Buffer：channel.read(byteBuffer);
2).数据从Client到Buffer：byteBuffer.put(...);

1).数据从Buffer到Channel：channel.write(byteBuffer);
2).数据从Buffer到Server：byteBuffer.get(...);

ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();

serverSocketChannel.close();

while(true){
 SocketChannel socketChannel = serverSocketChannel.accept();
 clientChannel.configureBlocking(false);
}

SocketChannel clientChannel = SocketChannel.open();
clientChannel.configureBlocking(false);
clientChannel.connect(new InetSocketAddress(port));
clientChannel.register(selector, SelectionKey.OP_CONNECT);

selectionKey.isAcceptable();
selectionKey.isConnectable();
selectionKey.isReadable();
selectionKey.isWritable();

Channel channel = selectionKey.channel();
Selector selector = selectionKey.selector();

clientChannel.register(key.selector(), SelectionKey.OP_READ,ByteBuffer.allocateDirect(1024));

selectionKey.attach(Object);
Object anthorObj = selectionKey.attachment();

package cn.blog.test.NioTest;
import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.*;
import java.nio.charset.Charset;
import java.util.Iterator;
import java.util.Set;
public class MyNioServer {
 private Selector selector;   //创建一个选择器
 private final static int port = 8686;
 private final static int BUF_SIZE = 10240;
 private void initServer() throws IOException {
  //创建通道管理器对象selector
  this.selector=Selector.open();
  //创建一个通道对象channel
  ServerSocketChannel channel = ServerSocketChannel.open();
  channel.configureBlocking(false);  //将通道设置为非阻塞
  channel.socket().bind(new InetSocketAddress(port));  //将通道绑定在8686端口
  //将上述的通道管理器和通道绑定，并为该通道注册OP_ACCEPT事件
  //注册事件后，当该事件到达时，selector.select()会返回（一个key），如果该事件没到达selector.select()会一直阻塞
  SelectionKey selectionKey = channel.register(selector,SelectionKey.OP_ACCEPT);
  while (true){  //轮询
   selector.select();   //这是一个阻塞方法，一直等待直到有数据可读，返回值是key的数量（可以有多个）
   Set keys = selector.selectedKeys();   //如果channel有数据了，将生成的key访入keys集合中
   Iterator iterator = keys.iterator();  //得到这个keys集合的迭代器
   while (iterator.hasNext()){    //使用迭代器遍历集合
    SelectionKey key = (SelectionKey) iterator.next();  //得到集合中的一个key实例
    iterator.remove();   //拿到当前key实例之后记得在迭代器中将这个元素删除，非常重要，否则会出错
    if (key.isAcceptable()){   //判断当前key所代表的channel是否在Acceptable状态，如果是就进行接收
     doAccept(key);
    }else if (key.isReadable()){
     doRead(key);
    }else if (key.isWritable() && key.isValid()){
     doWrite(key);
    }else if (key.isConnectable()){
     System.out.println("连接成功！");
    }
   }
  }
 }
 public void doAccept(SelectionKey key) throws IOException {
  ServerSocketChannel serverChannel = (ServerSocketChannel) key.channel();
  System.out.println("ServerSocketChannel正在循环监听");
  SocketChannel clientChannel = serverChannel.accept();
  clientChannel.configureBlocking(false);
  clientChannel.register(key.selector(),SelectionKey.OP_READ);
 }
 public void doRead(SelectionKey key) throws IOException {
  SocketChannel clientChannel = (SocketChannel) key.channel();
  ByteBuffer byteBuffer = ByteBuffer.allocate(BUF_SIZE);
  long bytesRead = clientChannel.read(byteBuffer);
  while (bytesRead>0){
   byteBuffer.flip();
   byte[] data = byteBuffer.array();
   String info = new String(data).trim();
   System.out.println("从客户端发送过来的消息是："+info);
   byteBuffer.clear();
   bytesRead = clientChannel.read(byteBuffer);
  }
  if (bytesRead==-1){
   clientChannel.close();
  }
 }
 public void doWrite(SelectionKey key) throws IOException {
  ByteBuffer byteBuffer = ByteBuffer.allocate(BUF_SIZE);
  byteBuffer.flip();
  SocketChannel clientChannel = (SocketChannel) key.channel();
  while (byteBuffer.hasRemaining()){
   clientChannel.write(byteBuffer);
  }
  byteBuffer.compact();
 }
 public static void main(String[] args) throws IOException {
  MyNioServer myNioServer = new MyNioServer();
  myNioServer.initServer();
 }
}

package cn.blog.test.NioTest;
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.SocketChannel;
import java.util.Iterator;
public class MyNioClient {
 private Selector selector;   //创建一个选择器
 private final static int port = 8686;
 private final static int BUF_SIZE = 10240;
 private static ByteBuffer byteBuffer = ByteBuffer.allocate(BUF_SIZE);
 private void initClient() throws IOException {
  this.selector = Selector.open();
  SocketChannel clientChannel = SocketChannel.open();
  clientChannel.configureBlocking(false);
  clientChannel.connect(new InetSocketAddress(port));
  clientChannel.register(selector, SelectionKey.OP_CONNECT);
  while (true){
   selector.select();
   Iterator<SelectionKey> iterator = selector.selectedKeys().iterator();
   while (iterator.hasNext()){
    SelectionKey key = iterator.next();
    iterator.remove();
    if (key.isConnectable()){
     doConnect(key);
    }else if (key.isReadable()){
     doRead(key);
    }
   }
  }
 }
 public void doConnect(SelectionKey key) throws IOException {
  SocketChannel clientChannel = (SocketChannel) key.channel();
  if (clientChannel.isConnectionPending()){
   clientChannel.finishConnect();
  }
  clientChannel.configureBlocking(false);
  String info = "服务端你好!!";
  byteBuffer.clear();
  byteBuffer.put(info.getBytes("UTF-8"));
  byteBuffer.flip();
  clientChannel.write(byteBuffer);
  //clientChannel.register(key.selector(),SelectionKey.OP_READ);
  clientChannel.close();
 }
 public void doRead(SelectionKey key) throws IOException {
  SocketChannel clientChannel = (SocketChannel) key.channel();
  clientChannel.read(byteBuffer);
  byte[] data = byteBuffer.array();
  String msg = new String(data).trim();
  System.out.println("服务端发送消息："+msg);
  clientChannel.close();
  key.selector().close();
 }
 public static void main(String[] args) throws IOException {
  MyNioClient myNioClient = new MyNioClient();
  myNioClient.initClient();
 }
}