java nio 通信服务器、客户端完整例子

package com.lzx.TestServer; import java.io.IOException; import java.net.InetSocketAddress; import java.nio.ByteBuffer; import java.nio.CharBuffer; import java.nio.channels.Selector; import java.nio.channels.ServerSocketChannel; import java.nio.channels.SelectionKey; import java.nio.channels.SocketChannel; import java.nio.charset.Charset; import java.nio.charset.CharsetDecoder; import java.nio.charset.CharsetEncoder; import java.util.Iterator; public class Server { private static final int SERVERPORT=8890; public static void main(String[] args) { Selector selector = null; ServerSocketChannel server = null; try{ selector = Selector.open(); server = ServerSocketChannel.open(); InetSocketAddress ip = new InetSocketAddress(SERVERPORT); server.socket().bind(ip); server.configureBlocking(false); server.register(selector,SelectionKey.OP_ACCEPT); System.out.println("服务器开始接受客户端连接"); while(true){ // select try { selector.select(); } catch (Exception e) { // TODO: handle exception // System.out.println("select 错误"); } Iterator<SelectionKey>it = selector.selectedKeys().iterator(); // deal everyone while(it.hasNext()){ SelectionKey key = it.next(); it.remove(); // acceptable if(key.isAcceptable()){ ServerSocketChannel server2 = (ServerSocketChannel)key.channel(); SocketChannel channel = server2.accept(); channel.configureBlocking(false); channel.register(selector, SelectionKey.OP_READ|SelectionKey.OP_WRITE); System.out.println("客户端：" + channel.socket().getInetAddress().getHostName() + ":" + channel.socket().getPort() + " 连接上了"); } // readable if(key.isReadable()){ // System.out.println("可读"); SocketChannel channel = (SocketChannel)key.channel(); CharsetDecoder decoder = Charset.forName("UTF-8").newDecoder(); ByteBuffer buffer = ByteBuffer.allocate(50); try{ channel.read(buffer); }catch(IOException e){ // 客户端异常断开连接 System.out.println("客户端：" + channel.socket().getInetAddress().getHostName() + ":" + channel.socket().getPort() + " 已断开连接"); channel.close(); continue; } buffer.flip(); String msg = decoder.decode(buffer).toString(); if (msg.equals("退出!@#$%")) { // 客户端主动断开连接 System.out.println("客户端：" + channel.socket().getInetAddress().getHostName() + ":" + channel.socket().getPort() + " 已断开连接"); channel.close(); continue; } System.out.println( channel.socket().getInetAddress().getHostName() + ":" + channel.socket().getPort() + "：" + msg); if (key.isWritable()) { // System.out.println("可写"); CharsetEncoder encoder = Charset.forName("UTF-8").newEncoder(); try { channel.write(encoder.encode(CharBuffer.wrap("server receive your message "))); } catch (IOException e) { // TODO: handle exception System.out.println("写入io错误"); } } } } } }catch(IOException e){ e.printStackTrace(); } finally{ try{ selector.close(); server.close(); }catch(IOException e){} } } }