//客户但
package com.example.demo.nio;
import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.SocketChannel;
import java.util.Iterator;
import java.util.Set;
public class NIOClient {
private static boolean isEnding = false;
//表示数字
private static int flag= 0;
//缓冲区大小
private static int BLOCK = 4096;
//接受数据缓冲区
private static ByteBuffer sendbuffer = ByteBuffer.allocate(BLOCK);
//发送数据缓冲区
private static ByteBuffer receiveBuffer = ByteBuffer.allocate(BLOCK);
//服务器地址
private final static InetSocketAddress SERVER_ADDRESS = new InetSocketAddress("localhost",8888);
public static void main(String[] args) throws IOException {
//打开socker通道
SocketChannel socketChannel = SocketChannel.open();
//设置为非阻塞模式
socketChannel.configureBlocking(false);
//打开选择器
Selector selector = Selector.open();
//注册连接服务端socket动作
socketChannel.register(selector,SelectionKey.OP_CONNECT);
//连接
socketChannel.connect(SERVER_ADDRESS);
//分配缓冲区内存大小
Set<SelectionKey> selectionKeys;
Iterator<SelectionKey> iterator;
SelectionKey selectionKey;
SocketChannel client;
String receiveText;
String sendText;
int count = 0;
while (!isEnding){
//选择一组键,其对应的通道已为 I/O 操作准备就绪
//此方法执行处于阻塞模式的选择操作
selector.select();
//返回此选择器的已选择的键集
selectionKeys = selector.selectedKeys();
iterator = selectionKeys.iterator();
while (iterator.hasNext()){
selectionKey = iterator.next();
if(selectionKey.isConnectable()){
System.out.println("client connect");
client = (SocketChannel) selectionKey.channel();
//判断此通道伤是否正在进行连接操作
//完成套接字通道的连接过程
if(client.isConnectionPending()){
client.finishConnect();
System.out.println("完成连接!");
sendbuffer.clear();
sendbuffer.put("Hello,Server".getBytes());
sendbuffer.flip();
client.write(sendbuffer);
}
client.register(selector,SelectionKey.OP_READ);
}else if(selectionKey.isReadable()){
client = (SocketChannel) selectionKey.channel();
receiveBuffer.clear();
count = client.read(receiveBuffer);
if(count >0){
receiveText = new String(receiveBuffer.array(),0,count);
System.out.println("客户端接受服务器端的数据--:"+receiveText);
client.register(selector,SelectionKey.OP_WRITE);
}
}else if (selectionKey.isWritable()) {
sendbuffer.clear();
client = (SocketChannel) selectionKey.channel();
sendText = "message from client--" + (flag++);
sendbuffer.put(sendText.getBytes());
//将缓冲区各标志复位,因为向里面put了数据标志被改变要想从中读取数据发向服务器,就要复位
sendbuffer.flip();
client.write(sendbuffer);
System.out.println("客户端向服务器端发送数据--:"+sendText);
client.register(selector, SelectionKey.OP_READ);
isEnding = true;
}
}
selectionKeys.clear();
}
selector.close();
socketChannel.close();
}
}
//服务端
package com.example.demo.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.util.Iterator;
import java.util.Set;
public class NIOServer {
//标识数字
private int flag = 0;
//缓冲区大小
private int BLOCK = 4096;
//接收数据缓冲区
private ByteBuffer sendBuffer = ByteBuffer.allocate(BLOCK);
//发送数据缓冲区
private ByteBuffer receiveBuffer = ByteBuffer.allocate(BLOCK);
private Selector selector;
public NIOServer(int port) throws IOException{
/**
* 以下的所有说明均已linux系统底层进行说明:
* nio 的底层实现是 epoll 模式,采用多路复用技术,对nio的代码进行深入分析,结合epoll的底层实现
* 进行详细的说明
* 1.linux网络编程是两个进程之间的通信,跨集群合网络
* 2.开启一个socket线程,在linux系统上任何操作均以文件句柄数表示,默认情况下
* 一个线程可以打开1024个句柄,也就说最多同时支持1024个网络连接请求。阿里云默认打开65535个文件
* 句柄,通常情况下,1G内存最多可以打开10w个句柄数
*
*
*/
//打开服务器套接字通道
//底层;在linux上面开启socker服务,启动一个线程,绑定ip地址和端口号
ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();
//服务器配置为非阻塞
serverSocketChannel.configureBlocking(false);
//检索与此通道关联的服务器套接字
ServerSocket serverSocket = serverSocketChannel.socket();
//进行服务绑定
serverSocket.bind(new InetSocketAddress(port));
//通过open()方法找到Selector
//底层:开启epoll,为当前socket服务创建epoll服务,epoll_create
selector = Selector.open();
//注册到selector
/**
* 底层:
* 1.将当前的epoll,服务器地址,端口号绑定,如果有连接请求,直接添加到epoll中,epoll的底层是红黑树,
* 可以快速的实现连接的查找和状态更新。如果有新的连接过来,直接存放到epoll中。如果有连接过期,中断,
* 会从epoll中删除。
* 2.通过epoll_ctl添加到epoll的同时,会注册一个回调函数给内核,当网卡有数据来的时候,会通知内核,内核
* 调用回调函数,将当前内核数据的事件状态添加到list链表中
*/
serverSocketChannel.register(selector,SelectionKey.OP_ACCEPT);
System.out.println("Server Start:"+port);
}
//监听
private void listen() throws IOException{
while (true){
//选择一组键,并且相应得通道已经打开
/**
* epoll底层维护一个链表,rdlist,基于事件驱动模式,当网卡有数据请求过来,会发起硬件中断,通知内核已经有来了。内核调用
* 回调函数,将当前的事件添加到rdlist中,将当前可用的rdlist列表发送给用户态,用户去遍历rdlist中的事件,进行处理
*/
int readyChannels = selector.select();
if(readyChannels == 0) continue;
//返回此选择器得已选择键集
Set<SelectionKey> selectionKeys = selector.selectedKeys();
Iterator<SelectionKey> iterator = selectionKeys.iterator();
while (iterator.hasNext()){
SelectionKey selectionKey = iterator.next();
//获取当前epoll的rdlist复制到用户态,遍历,同时删除当前rdlist中的事件
iterator.remove();
handleKEY(selectionKey);
}
}
}
//处理请求
private void handleKEY(SelectionKey selectionKey) throws IOException {
//接受请求
ServerSocketChannel server = null;
SocketChannel client = null;
String receiveText;
String sendText;
int count = 0;
//测试此键的通道是否已准备好接受新的套接字连接
if(selectionKey.isAcceptable()){
System.out.println("测试此键的通道是否已准备好接受新的套接字连接");
//返回为止创建此键的通道
server = (ServerSocketChannel) selectionKey.channel();
//接受次通道套接字的连接
//此方法返回的套接字通道(如果有)将处于阻塞模式
client = server.accept();
//配置为非阻塞
client.configureBlocking(false);
//注册到selector,等待连接
client.register(selector,SelectionKey.OP_READ);
}else if(selectionKey.isReadable()){
//返回为之创建此键的通道
client = (SocketChannel) selectionKey.channel();
//将缓冲区清空以备下次读取
receiveBuffer.clear();
//读取服务器发送来的数据到缓冲区
count = client.read(receiveBuffer);
if(count>0){
receiveText = new String(receiveBuffer.array(),0,count);
System.out.println("服务器端接受客户端数据--:"+receiveText);
client.register(selector,SelectionKey.OP_WRITE);
}
}else if(selectionKey.isWritable()){
//将缓冲区清空以备下次写入
sendBuffer.clear();
//返回为之创建此键的通道
client = (SocketChannel) selectionKey.channel();
sendText = "message form server --"+flag++;
//向缓冲区中输入数据
sendBuffer.put(sendText.getBytes());
//将缓冲区个标志复位,因为李米娜put了数据标志被改变要想从中读取数据发向服务器,就要复位
sendBuffer.flip();
//输出到通道
client.write(sendBuffer);
System.out.println("服务器端向客服端发送数据--:"+sendText);
client.register(selector,SelectionKey.OP_READ);
}
}
public static void main(String[] args) throws IOException {
int port = 8888;
NIOServer server = new NIOServer(port);
server.listen();
}
}