Java Socket编程（非阻塞多线程，NIO）
服务端：
服务器Server类
public class Server implements Runnable {
private int port;
private volatile boolean stop;
private Selector selector;
private ServerSocketChannel serverSocketChannel;
public Server(int port){
this.port = port;
}
public void init(){
try {
//打开一个选择器
selector = Selector.open();
//打开一个Server-Socket监听通道
serverSocketChannel = ServerSocketChannel.open();
//设置该通道为非阻塞模式
serverSocketChannel.configureBlocking(false);
//绑定端口
serverSocketChannel.socket().bind(new InetSocketAddress(port));
//将通道注册在选择器上面，并将准备连接状态作为通道订阅时间
serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);
stop = false;
System.out.println("服务器已经启动，端口号：" + port);
}catch (IOException e){
e.printStackTrace();
}
}
public void run() {
init();
while (!stop){
try {
//无论是否有读写事件发生，selector每隔1s被唤醒一次
selector.select(1000);
Set selectionKeys = selector.selectedKeys();
Iterator iterator = selectionKeys.iterator();
while (iterator.hasNext()){
SelectionKey selectionKey = iterator.next();
//判断是否准备好接收新进入的连接
if(selectionKey.isAcceptable()){
ServerSocketChannel serverSocketChannel = (ServerSocketChannel) selectionKey.channel();
//通过ServerSocketChannel的accept()创建SocketChannel实例
//完成该操作意味着完成TCP三次握手，TCP物理链路正式建立
SocketChannel socketChannel = serverSocketChannel.accept();
//设置为非阻塞
socketChannel.configureBlocking(false);
//在选择器注册，并订阅读事件
socketChannel.register(selector,SelectionKey.OP_READ);
}
if(selectionKey.isReadable()){
SocketChannel socketChannel = (SocketChannel) selectionKey.channel();
//创建byteBuffer，并开辟一个1M的缓冲区
ByteBuffer byteBuffer = ByteBuffer.allocate(1024);
//读取请求码流，返回读取到的字节数
int readBytes = socketChannel.read(byteBuffer);
//判断客户端是否断开
if(readBytes < 0){
selectionKey.cancel();
socketChannel.close();
return;
}
//读取到字节，对字节进行编解码
if(readBytes>0){
//将缓冲区从写模式切换到读模式
byteBuffer.flip();
//根据缓冲区可读字节数创建字节数组
byte[] bytes = new byte[byteBuffer.remaining()];
//向缓冲区读数据到字节数组
byteBuffer.get(bytes);
String expression = new String(bytes,"UTF-8");
System.out.println("服务器收到消息："+expression);
}
}
iterator.remove();
}
selectionKeys.clear();
}catch (IOException e){
e.printStackTrace();
}
}
//selector关闭后会自动释放里面管理的资源
if(selector != null){
try {
selector.close();
}catch (IOException e){
e.printStackTrace();
}
}
}
} 客户端：
客户端Client类
public class Client implements Runnable {
private String host;
private int port;
private Selector selector;
private SocketChannel socketChannel;
private volatile boolean stop;
private String name;
public Client(int port,String name){
this("localhost",port,name);
}
public Client(String host,int port,String name){
this.host = host;
this.port = port;
this.name = name;
}
public void init(){
try {
//打开一个选择器
selector = Selector.open();
//打开一个Socket监听通道
socketChannel = SocketChannel.open();
//设置该通道为非阻塞模式
socketChannel.configureBlocking(false);
//在非阻塞模式下，该方法在建立连接之前就会返回结果了，后续为了确认连接是否建立成功，可以调用finishConnect()
socketChannel.connect(new InetSocketAddress(host,port));
//订阅连接事件
socketChannel.register(selector, SelectionKey.OP_CONNECT);
stop = false;
}catch (IOException e){
e.printStackTrace();
}
}
public void run() {
init();
int i = 0;
while (!stop){
try {
//无论是否有读写事件发生，selector每隔1s被唤醒一次
selector.select(1000);
Set selectionKeys = selector.selectedKeys();
Iterator iterator = selectionKeys.iterator();
while (iterator.hasNext()){
SelectionKey selectionKey = iterator.next();
//判断是否连接到服务器
if(selectionKey.isConnectable()){
//判断连接是否建立成功
if(socketChannel.finishConnect()){
sendMsg(name+" Connect Success!");
socketChannel.register(selector,SelectionKey.OP_WRITE);
}
}
if(selectionKey.isWritable()){
sendMsg(name+" is saying \"Hello World\"!"+i++);
Thread.sleep(1000);
}
iterator.remove();
}
selectionKeys.clear();
}catch (ConnectException e){
System.out.println("连接失败!");
return;
}catch (IOException e){
e.printStackTrace();
}catch (InterruptedException e){
e.printStackTrace();
}
}
}
public void sendMsg(String expression) throws IOException{
byte[] bytes = expression.getBytes();
ByteBuffer byteBuffer = ByteBuffer.allocate(bytes.length);
byteBuffer.put(bytes);
//翻转缓冲区，执行的操作：
//1.将limit的位置设为position之后的一个位置
//2.将position的位置重置为0
byteBuffer.flip();
socketChannel.write(byteBuffer);
//清空缓冲区
byteBuffer.clear();
}
} 测试过程：
测试类TestNio
public class TestNio {
public static void main(String[] args) {
Thread server = new Thread(new Server(10086));
Thread client1 = new Thread(new Client(10086,"ONE"));
Thread client2 = new Thread(new Client(10086,"TWO"));
server.start();
client1.start();
client2.start();
}
}测试结果：
服务器已经启动，端口号：10086
服务器收到消息：TWO Connect Success!
服务器收到消息：ONE Connect Success!
服务器收到消息：ONE is saying "Hello World"!0
服务器收到消息：TWO is saying "Hello World"!0
服务器收到消息：ONE is saying "Hello World"!1
服务器收到消息：TWO is saying "Hello World"!1
服务器收到消息：ONE is saying "Hello World"!2
服务器收到消息：TWO is saying "Hello World"!2
服务器收到消息：ONE is saying "Hello World"!3
服务器收到消息：TWO is saying "Hello World"!3
服务器收到消息：ONE is saying "Hello World"!4
服务器收到消息：TWO is saying "Hello World"!4
服务器收到消息：ONE is saying "Hello World"!5
服务器收到消息：TWO is saying "Hello World"!5
服务器收到消息：ONE is saying "Hello World"!6
服务器收到消息：TWO is saying "Hello World"!6
服务器收到消息：ONE is saying "Hello World"!7
服务器收到消息：TWO is saying "Hello World"!7
服务器收到消息：ONE is saying "Hello World"!8
服务器收到消息：TWO is saying "Hello World"!8
服务器收到消息：ONE is saying "Hello World"!9
服务器收到消息：TWO is saying "Hello World"!9
服务器收到消息：ONE is saying "Hello World"!10
服务器收到消息：TWO is saying "Hello World"!10