我在网上也找到一个例子，但是没有客户端，我自己写了一个用ServerSocket连的客户端，但是连接上后不能写也不能读，不知道怎么回事，请高手解决。最好能给一个简单异步编程的例子。
下面是代码：
package org.scorpion.scoket;
/**
- @author chenjd */ import java.io.IOException; import java.net.InetAddress; import java.net.InetSocketAddress; import java.net.Socket; import java.nio.ByteBuffer; import java.nio.CharBuffer; import java.nio.channels.SelectableChannel; import java.nio.channels.SelectionKey; import java.nio.channels.Selector; import java.nio.channels.ServerSocketChannel; import java.nio.channels.SocketChannel; import java.nio.charset.CharacterCodingException; import java.nio.charset.Charset; import java.nio.charset.CharsetDecoder; import java.util.HashMap; import java.util.Iterator; import java.util.Set;
public class NBServer {
int port = 8090;
int BUFFERSIZE = 1024;
Selector selector = null;
ServerSocketChannel serverChannel = null;
HashMap clientChannelMap = null;// 用来存放每一个客户连接对应的套接字和通道
public NBServer(int port) {
this.clientChannelMap = new HashMap();
this.port = port;
}
public void initialize() throws IOException {
// 初始化，分别实例化一个选择器，一个服务器端可选择通道
this.selector = Selector.open();
this.serverChannel = ServerSocketChannel.open();
this.serverChannel.configureBlocking(false);
InetAddress localhost = InetAddress.getLocalHost();
InetSocketAddress isa = new InetSocketAddress(localhost, this.port);
this.serverChannel.socket().bind(isa);// 将该套接字绑定到服务器某一可用端口
}
// 结束时释放资源
public void finalize() throws IOException {
this.serverChannel.close();
this.selector.close();
}
// 将读入字节缓冲的信息解码
public String decode(ByteBuffer byteBuffer) throws CharacterCodingException {
Charset charset = Charset.forName("ISO-8859-1");
CharsetDecoder decoder = charset.newDecoder();
CharBuffer charBuffer = decoder.decode(byteBuffer);
String result = charBuffer.toString();
return result;
}
// 监听端口，当通道准备好时进行相应操作
public void portListening(String data) throws IOException, InterruptedException {
// 服务器端通道注册OP_ACCEPT事件
SelectionKey acceptKey = this.serverChannel.register(this.selector,
SelectionKey.OP_ACCEPT);
// 当有已注册的事件发生时,select()返回值将大于0
while (acceptKey.selector().select() > 0) {
System.out.println("event happened");
// 取得所有已经准备好的所有选择键
Set readyKeys = this.selector.selectedKeys();
// 使用迭代器对选择键进行轮询
Iterator i = readyKeys.iterator();
while (i.hasNext()) {
SelectionKey key = (SelectionKey) i.next();
i.remove();// 删除当前将要处理的选择键
if (key.isAcceptable()) {// 如果是有客户端连接请求
System.out.println("more client connect in!");
ServerSocketChannel nextReady = (ServerSocketChannel) key
.channel();
// 获取客户端套接字
Socket s = nextReady.accept().socket();
// 设置对应的通道为异步方式并注册感兴趣事件
s.getChannel().configureBlocking(false);
SelectionKey readWriteKey = s.getChannel().register(
this.selector,
SelectionKey.OP_READ | SelectionKey.OP_WRITE);
// 将注册的事件与该套接字联系起来
readWriteKey.attach(s);
// 将当前建立连接的客户端套接字及对应的通道存放在哈希表//clientChannelMap中
this.clientChannelMap.put(s, new ClientChInstance(s
.getChannel()));
} else if (key.isReadable()) {// 如果是通道读准备好事件
System.out.println("Readable");
// 取得选择键对应的通道和套接字
SelectableChannel nextReady = (SelectableChannel) key
.channel();
Socket socket = (Socket) key.attachment();
// 处理该事件，处理方法已封装在类ClientChInstance中
this.readFromChannel(socket.getChannel(),
(ClientChInstance) this.clientChannelMap
.get(socket));
} else if (key.isWritable()) {// 如果是通道写准备好事件
System.out.println("writeable");
// 取得套接字后处理，方法同上
Socket socket = (Socket) key.attachment();
SocketChannel channel = (SocketChannel) socket.getChannel();
// this.writeToChannel(channel, "This is from server!");
this.writeToChannel(channel, data);
}
}
}
}
// 对通道的写操作
public void writeToChannel(SocketChannel channel, String message)
throws IOException {
ByteBuffer buf = ByteBuffer.wrap(message.getBytes());
int nbytes = channel.write(buf);
}
// 对通道的读操作
public void readFromChannel(SocketChannel channel,
ClientChInstance clientInstance) throws IOException,
InterruptedException {
ByteBuffer byteBuffer = null;
try{
byteBuffer = ByteBuffer.allocate(BUFFERSIZE);
int nbytes = channel.read(byteBuffer);
}catch(Exception e){
clientChannelMap.remove(channel.socket());
channel.close();
e=null;
return;
}
byteBuffer.flip();
String result = this.decode(byteBuffer);
// 当客户端发出”@exit”退出命令时，关闭其通道
if (result.indexOf("@exit") >= 0||result.indexOf("q")>=0) {
channel.close();
}
// else if(result.indexOf("@close") >= 0){//关闭服务
// channel.close();
// this.finalize();
// }
else {
clientInstance.append(result.toString());
// 读入一行完毕，执行相应操作
if (result.indexOf("\n") >= 0) {
System.out.println("client input" + result);
clientInstance.execute();
}
}
}
// 该类封装了怎样对客户端的通道进行操作，具体实现可以通过重载execute()方法
public class ClientChInstance {
SocketChannel channel;
StringBuffer buffer = new StringBuffer();
public ClientChInstance(SocketChannel channel) {
this.channel = channel;
}
public void execute() throws IOException {
String message = "This is response after reading from channel!";
writeToChannel(this.channel, message);
buffer = new StringBuffer();
}
// 当一行没有结束时，将当前字窜置于缓冲尾
public void append(String values) {
buffer.append(values);
}
}
// 主程序
public static void main(String[] args) {
NBServer nbServer = new NBServer(8090);
try {
nbServer.initialize();
} catch (Exception e) {
e.printStackTrace();
System.exit(-1);
}
try {
nbServer.portListening("This is from server!");
} catch (Exception e) {
e.printStackTrace();
}
}
}
我写的客户端：
package org.scorpion.scoket;
import java.io.OutputStream;
import java.net.Socket;
public class TCPClient {
public static void main(String[] args) throws Exception {
Socket s = new Socket("172.22.71.146", 8000);
OutputStream os = s.getOutputStream();
byte[] by="ksfsksjfklsdjflsdj".getBytes();
os.write(by);
s.close();
}
}
