JAVA nio的一个简单的例子

package com.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.security.MessageDigest; import java.security.NoSuchAlgorithmException; import java.util.Iterator; import java.util.Set; import com.util.String2Hex; public class MyServer { int port; ServerSocketChannel channel4Accept; Selector selector; public MyServer(int port) throws IOException { this.port=port; channel4Accept = ServerSocketChannel.open(); channel4Accept.configureBlocking(false); ServerSocket ss = channel4Accept.socket(); ss.bind(new InetSocketAddress(port)); selector = Selector.open(); channel4Accept.register(selector, SelectionKey.OP_ACCEPT); } public void run() throws IOException, InterruptedException, NoSuchAlgorithmException { while(true) { int nKeys = selector.select(); Iterator<SelectionKey> it = selector.selectedKeys().iterator(); SelectionKey aKey=null; while(it.hasNext()) { aKey = it.next(); it.remove(); if(aKey.isAcceptable()) { ServerSocketChannel ssc = (ServerSocketChannel) aKey.channel(); SocketChannel channel4Talk = ssc.accept(); if(channel4Talk == null) continue; channel4Talk.configureBlocking(false); channel4Talk.register(selector, SelectionKey.OP_READ); } else if(aKey.isReadable()) { SocketChannel channel4Talk = (SocketChannel)aKey.channel(); ByteBuffer buffer = ByteBuffer.allocate(1024); buffer.clear(); int len=channel4Talk.read(buffer); String msg = new String(buffer.array(),0,len); System.out.println("receive message��"+msg); MessageDigest md = MessageDigest.getInstance("md5"); md.update(msg.getBytes()); byte[] digest = md.digest(); String ret = String2Hex.byte2Hex(digest); System.out.println("digest = "+ret); buffer.clear(); buffer.put(ret.getBytes()); buffer.flip(); channel4Talk.write(buffer); channel4Talk.close(); } else if(aKey.isWritable()) { System.out.println("writable events..."); } } } } }