Java review--NIO实例:实现服务端和客户端的简单通信

package nio;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.ServerSocket;
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 NIOServer {

private int flag =1;
private int blockSize=4096;
private ByteBuffer sendbuffer =ByteBuffer.allocate(blockSize);//发送数据缓冲区
private ByteBuffer receivebuffer =ByteBuffer.allocate(blockSize);//接收数据缓冲区
private Selector selector;//选择器

public NIOServer(int port) throws IOException{
ServerSocketChannel serverSocketChannel=ServerSocketChannel.open();
//设置是否组阻塞
serverSocketChannel.configureBlocking(false);
//创建客户端和服务端的socket.socket网络套接字，用来向网络发送请求，或者应答请求。
ServerSocket serverSocket=serverSocketChannel.socket();
//绑定socket地址，IP端口
serverSocket.bind(new InetSocketAddress(port));
//打开筛选器
selector=Selector.open();

// 将选择器绑定到监听信道,只有非阻塞信道才可以注册选择器.并在注册过程中指出该信道可以进行Accept操作，返回key
serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);
System.out.println("Server start ->"+port);
}

//NIOServer的监听事件
public void listen() throws IOException{
while(true){
selector.select();
Set<SelectionKey> selectionKeys=selector.selectedKeys();
Iterator<SelectionKey> itetor=selectionKeys.iterator();
while(itetor.hasNext()){
//负责多线程并发的安全的key
SelectionKey selectionKey=itetor.next();
itetor.remove();
//业务逻辑
handleKey(selectionKey);
}
}
}

//业务逻辑
public void handleKey(SelectionKey selectionKey) throws IOException{
//服务端监听通道
ServerSocketChannel server=null;
SocketChannel client=null;
String reciveText;
String sendText;
int count=0;
if(selectionKey.isAcceptable()){
//服务端接收客户端信息
server=(ServerSocketChannel)selectionKey.channel();
client=server.accept();
client.configureBlocking(false);
client.register(selector, selectionKey.OP_READ);
}else if(selectionKey.isReadable()){
//服务端读取客户端信息
client =(SocketChannel)selectionKey.channel();
count =client.read(receivebuffer);
if(count>0){
reciveText =new String(receivebuffer.array(),0,count);
System.out.println("服务端接收到客户端的信息："+reciveText);
client.register(selector,selectionKey.OP_WRITE);
}
}else if (selectionKey.isWritable()){
//服务端发送数据给客户端
sendbuffer.clear();
client=(SocketChannel)selectionKey.channel();
sendText="mag send to client:"+flag++;
sendbuffer.put(sendText.getBytes());
sendbuffer.flip();
client.write(sendbuffer);
System.out.println("服务端发送数据给客户端："+sendText);

}

}

public static void main(String[] args) throws IOException {
int port =7080;
NIOServer server =new NIOServer(port);
server.listen();
}

}

package nio;

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;
import java.util.Set;

public class NIOClient {
private static  int flag =1;
private static int blockSize=4096;
private static ByteBuffer sendbuffer =ByteBuffer.allocate(blockSize);//发送数据缓冲区
private static  ByteBuffer receivebuffer =ByteBuffer.allocate(blockSize);//接收数据缓冲区

//Socket地址：ip+端口
private final static InetSocketAddress serverAddress=new InetSocketAddress("127.0.0.1",7080);

public static void main(String[] args) throws IOException {
//打开通道
SocketChannel socketChannel=SocketChannel.open();
//通道设置成非阻塞模式
socketChannel.configureBlocking(false);
//打开筛选器
Selector selector =Selector.open();
//注册选择器
socketChannel.register(selector, SelectionKey.OP_CONNECT);
socketChannel.connect(serverAddress);

Set<SelectionKey> selectionKeys;
Iterator<SelectionKey> iterator;
SelectionKey selectionKey;
SocketChannel client;
String receiveTest;
String sendText;
int count=0;
while(true){
selectionKeys =selector.selectedKeys();
iterator=selectionKeys.iterator();
while(iterator.hasNext()){
selectionKey=iterator.next();
if(selectionKey.isConnectable()){
System.out.println("client connect");
client =(SocketChannel)selectionKey.channel();
if(client.isConnectionPending()){
client.finishConnect();
System.out.println("客户端完成连接操作！");
sendbuffer.clear();
sendbuffer.put("Hello,Server".getBytes());
sendbuffer.flip();
client.write(sendbuffer);
}
client.register(selector, SelectionKey.OP_READ);

}if(selectionKey.isReadable()){
client=(SocketChannel)selectionKey.channel();
receivebuffer.clear();
count=client.read(receivebuffer);
if(count>0){
receiveTest =new String(receivebuffer.array(),0,count);
System.out.println("客户端接收到服务端的数据:"+receiveTest);
client.register(selector,SelectionKey.OP_WRITE);

}
}if(selectionKey.isWritable()){
sendbuffer.clear();
client=(SocketChannel)selectionKey.channel();
sendText="Msg from client--->"+flag++;
sendbuffer.put(sendText.getBytes());
sendbuffer.flip();
client.write(sendbuffer);
System.out.println("客户端发送方数据给服务端："+sendText);
client.register(selector, SelectionKey.OP_READ);

}
}

selectionKeys.clear();
}
}
}