package nioDemo;
import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.SocketChannel;
import java.nio.charset.Charset;
import java.util.Iterator;
import java.util.Random;
import java.util.Set;
/*客户端:客户端每隔1~2秒自动向服务器发送数据，接收服务器接收到数据并显示*/
public class ClientSocketChannelDemo {
public static class TCPEchoClient implements Runnable{
/*客户端线程名*/
private String name;
private Random rnd = new Random();
/*服务器的ip地址+端口port*/
private InetSocketAddress remoteAddress;
public TCPEchoClient(String name, InetSocketAddress remoteAddress){
this.name = name;
this.remoteAddress = remoteAddress;
}
@Override
public void run(){
/*创建解码器*/
Charset utf8 = Charset.forName("UTF-8");
Selector selector;
try {
/*创建TCP通道*/
SocketChannel sc = SocketChannel.open();
/*设置通道为非阻塞*/
sc.configureBlocking(false);
/*创建选择器*/
selector = Selector.open();
/*注册感兴趣事件*/
int interestSet = SelectionKey.OP_READ | SelectionKey.OP_WRITE;
/*向选择器注册通道*/
sc.register(selector, interestSet, new Buffers(256, 256));
/*向服务器发起连接,一个通道代表一条tcp链接*/
sc.connect(remoteAddress);
/*等待三次握手完成*/
while(!sc.finishConnect()){
;
}
System.out.println(name + " " + "finished connection");
} catch (IOException e) {
System.out.println("client connect failed");
return;
}
/*与服务器断开或线程被中断则结束线程*/
try{
int i = 1;
while(!Thread.currentThread().isInterrupted()){
/*阻塞等待*/
selector.select();
/*Set中的每个key代表一个通道*/
Set<SelectionKey> keySet = selector.selectedKeys();
Iterator<SelectionKey> it = keySet.iterator();
/*遍历每个已就绪的通道，处理这个通道已就绪的事件*/
while(it.hasNext()){
SelectionKey key = it.next();
/*防止下次select方法返回已处理过的通道*/
it.remove();
/*通过SelectionKey获取对应的通道*/
Buffers buffers = (Buffers)key.attachment();
ByteBuffer readBuffer = buffers.getReadBuffer();
ByteBuffer writeBuffer = buffers.gerWriteBuffer();
/*通过SelectionKey获取通道对应的缓冲区*/
SocketChannel sc = (SocketChannel) key.channel();
/*表示底层socket的读缓冲区有数据可读*/
if(key.isReadable()){
/*从socket的读缓冲区读取到程序定义的缓冲区中*/
sc.read(readBuffer);
readBuffer.flip();
/*字节到utf8解码*/
CharBuffer cb = utf8.decode(readBuffer);
/*显示接收到由服务器发送的信息*/
System.out.println(cb.array());
readBuffer.clear();
}
/*socket的写缓冲区可写*/
if(key.isWritable()){
writeBuffer.put((name + " " + i).getBytes("UTF-8"));
writeBuffer.flip();
/*将程序定义的缓冲区中的内容写入到socket的写缓冲区中*/
sc.write(writeBuffer);
writeBuffer.clear();
i++;
}
}
Thread.sleep(1000 + rnd.nextInt(1000));
}
}catch(InterruptedException e){
System.out.println(name + " is interrupted");
}catch(IOException e){
System.out.println(name + " encounter a connect error");
}finally{
try {
selector.close();
} catch (IOException e1) {
System.out.println(name + " close selector failed");
}finally{
System.out.println(name + " closed");
}
}
}
}
public static void main(String[] args) throws InterruptedException{
InetSocketAddress remoteAddress = new InetSocketAddress("192.168.1.100", 8080);
Thread ta = new Thread(new TCPEchoClient("thread a", remoteAddress));
Thread tb = new Thread(new TCPEchoClient("thread b", remoteAddress));
Thread tc = new Thread(new TCPEchoClient("thread c", remoteAddress));
Thread td = new Thread(new TCPEchoClient("thread d", remoteAddress));
ta.start();
tb.start();
tc.start();
Thread.sleep(5000);
/*结束客户端a*/
ta.interrupt();
/*开始客户端d*/
td.start();
}
}
5.2 UDP示例
客户端非阻塞模式，服务器端阻塞模式
1）服务器端代码（服务器端只有一个通道，对应一个读缓冲区，一个写缓冲区，所以使用非阻塞方式容易发生数据混乱）