package NetworkProgramming.SocketTest;

import java.io.IOException;

import java.net.InetAddress;

import java.net.InetSocketAddress;

import java.nio.ByteBuffer;

import java.nio.channels.*;

import java.nio.charset.Charset;

public class NServer {

//定义检测所有Channel状态的Selector

private Selector selector = null;

static final int PORT = 30000;

//定义实现编码、解码的字符集对象

private Charset charset = Charset.forName("UTF-8");

public void init() throws IOException {

selector = Selector.open();

//打开一个ServerSocketChannel实例

ServerSocketChannel server = ServerSocketChannel.open();

InetSocketAddress isa = new InetSocketAddress("127.0.0.1", PORT);

//绑定到具体Ip

server.bind(isa);

//设置非阻塞方式

server.configureBlocking(false);

//注册到selector

server.register(selector, SelectionKey.OP_ACCEPT);//server只允许accept

//获取到IO处理,否则阻塞等待

while (selector.select() > 0) {

//一次处理selector上的每个已经选择的SelectorKey(即需要IO)

for (SelectionKey sk : selector.selectedKeys()) {

//先从中删除待处理此sk

selector.selectedKeys().remove(sk);

//如果此sk是连接请求

if (sk.isAcceptable()) {

//接受连接

SocketChannel sc = server.accept();

//设置费阻塞模式

sc.configureBlocking(false);

//将该SocketChannel注册到selector

sc.register(selector, SelectionKey.OP_READ);

//将sk对应的channel设置成准备接受其它请求

sk.interestOps(SelectionKey.OP_ACCEPT);

}

//如果对应的sk得channel有对应的的数据需要读取

if (sk.isReadable()) {

//获取该SelectionKey对应的Channel，该Channel中有可读数据

SocketChannel sc = (SocketChannel) sk.channel();

//Buffer

ByteBuffer buff = ByteBuffer.allocate(16);

String content = "";

//开始读取数据

try {

while ((sc.read(buff)) > 0) {

System.out.println("before pos is :" + buff.position());

buff.flip();

System.out.println("after pos is :" + buff.position());

content += charset.decode(buff);

System.out.println("finally pos is :" + buff.position());

}

System.out.println("读取的数据:" + content);

//将sk对应的Channel设置成下一次读取

sk.interestOps(SelectionKey.OP_READ);

}

//如果捕获到sk对应的Channel出现异常,表名该Channel对应的client出现了问题,则取消此sk对应的注册

catch (IOException ioe) {

sk.cancel();

if (sk.channel() != null) {

sk.channel().close();

}

}

//如果content的长度大于0,级聊天信息不为空

if (content.length() > 0) {

//遍历SelectionKey

for (SelectionKey key : selector.keys()) {

//获取对应channel

Channel targetChannel = key.channel();

if (targetChannel instanceof SocketChannel) {

//写入

SocketChannel dest = (SocketChannel) targetChannel;

dest.write(charset.encode(content));

}

}

}

}

}

}

}

public static void main(String[] args) throws IOException {

new NServer().init();

}

}