jdk提供的NIO使用：
博主抄写了网上的demo，略作修改与调整,原文链接：
1、服务端代码：
package com.test3;
import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.util.Iterator;
/**
* NIO服务端代码
* @author http://
* @author ZX
* 监听客户端连接，接收、发送消息
*
*/
public class AServer {
public static void main(String[]args)throws Exception{
System.out.println("=================");
//创建选择器
Selector selector = Selector.open();
//创建打开服务端的监听
ServerSocketChannel sChannel = ServerSocketChannel.open();
//绑定本地地址
sChannel.socket().bind(new InetSocketAddress(9999));
//设置非阻塞模式
sChannel.configureBlocking(false);
//将通道绑定到选择器，非阻塞通道才能注册到选择器,第二个参数好像是方式或者操作吧
sChannel.register(selector, SelectionKey.OP_ACCEPT);
TcpProtocal protocol = new TcpProtocal();
//循环监听等待
while (true){
//
if(selector.select(3000)==0){
System.out.println("继续等待");
continue;
}
//间听到的可操作集合
Iterator<SelectionKey> keyIter = selector.selectedKeys().iterator();
while (keyIter.hasNext()){
SelectionKey key = keyIter.next();
//这是干嘛的？获取下下个？一点用没有啊？？？
/* SelectionKey key1;
if(keyIter.hasNext()){
key1 = keyIter.next();
}*/
try {
//如果有客户端连接请求
if(key.isAcceptable()){
protocol.handleAccept(key);
}
//如果有数据发送
if(key.isReadable()){
protocol.handleRead(key);
protocol.handleWrite(key);
}
//是否有效，是否可发送给客户端
if(key.isValid()&&key.isWritable()){
//protocol.handleWriteMsg(key,"我服务端在这里说点事情");
}
}catch (IOException e){
keyIter.remove();
e.printStackTrace();
continue;
}
//删除处理过的键
keyIter.remove();
}
}
}
}
2、协议：
package com.test3;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.nio.charset.Charset;
/**
* 定义一个协议传输信息
*/
public class TcpProtocal {
private int bufferSize=1024;
/** 接受一个SocketChannel处理*/
public void handleAccept(SelectionKey key) throws Exception{
//返回创建此键的通道，接收客户端建立连接的请求，并返回socketChannel对象
SocketChannel clientChannel=((ServerSocketChannel)key.channel()).accept();
//设置非阻塞
clientChannel.configureBlocking(false);
//注册到selector
clientChannel.register(key.selector(),SelectionKey.OP_READ, ByteBuffer.allocate(bufferSize));
}
/** 从一个一个SocketChannel读取信息*/
public void handleRead(SelectionKey key) throws Exception{
//获得与客户端通信的通道
SocketChannel clientChannel=(SocketChannel)key.channel();
//得到并清空缓冲区并清空缓冲区
ByteBuffer buffer= (ByteBuffer)key.attachment();
buffer.clear();
//读取信息获得的字节数
int byteRead = clientChannel.read(buffer);
if(byteRead==-1){
clientChannel.close();
}else{
//将缓冲区准备为数据传状态
buffer.flip();
//将字节转换为UTF-16
String receivedStr = Charset.forName("UTF-8").newDecoder().decode(buffer).toString();
System.out.println("接收到来自"+clientChannel.socket().getRemoteSocketAddress()+"信息"+receivedStr);
key.interestOps(SelectionKey.OP_READ|SelectionKey.OP_WRITE);
/*String sendStr ="已收到信息";
buffer=ByteBuffer.wrap(sendStr.getBytes("UTF-8"));
clientChannel.write(buffer);
//设置为下依稀读取写入做准备
key.interestOps(SelectionKey.OP_READ|SelectionKey.OP_WRITE);*/
}
}
/** 向一个一个SocketChannel写入信息*/
public void handleWrite(SelectionKey key) throws Exception{
handleWriteMsg(key,null);
}
/** 向一个一个SocketChannel写入信息*/
public void handleWriteMsg(SelectionKey key,String msg) throws Exception{
if(msg==null||"".equals(msg)){
msg="服务器主动说：已收到建立请求消息";
}
//获得与客户端通信的通道
SocketChannel clientChannel=(SocketChannel)key.channel();
//得到并清空缓冲区并清空缓冲区
ByteBuffer buffer= (ByteBuffer)key.attachment();
buffer.clear();
String sendStr =msg;
buffer=ByteBuffer.wrap(sendStr.getBytes("UTF-8"));
clientChannel.write(buffer);
//设置为下依稀读取写入做准备
key.interestOps(SelectionKey.OP_READ|SelectionKey.OP_WRITE);
}
}
3、客户端处理类：
package com.test3;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.SocketChannel;
import java.nio.charset.Charset;
public class TcpClientReadThread implements Runnable{
private Selector selector;
public TcpClientReadThread(Selector selector){
this.selector=selector;
new Thread(this).start();
}
public void run() {
try {
//select()方法只能使用一次，用过之后就会删除，每个连接到服务器的选择器都是独立的
while (selector.select()>0){
//遍历所有可以IO操作做的Channel对应的selectionKey
for(SelectionKey sk:selector.selectedKeys()){
//如果数据可读
if(sk.isReadable()){
//使用NIO读取Channel中可读数据
//获取通道信息
SocketChannel sc = (SocketChannel)sk.channel();
//创建缓冲区
ByteBuffer buffer = ByteBuffer.allocate(1024);
//读取数据到缓冲区
sc.read(buffer);
//吊用此方法为读取写入做准备
buffer.flip();
String receiveStr = Charset.forName("UTF-8").newDecoder().decode(buffer).toString();
System.out.println("收到服务器"+sc.socket().getRemoteSocketAddress()+"信息"+receiveStr);
//为下一次读取做准备
sk.interestOps(SelectionKey.OP_READ);
//删除正在处理的selectionKey
selector.selectedKeys().remove(sk);
}
}
}
}catch (Exception e){
e.printStackTrace();
}
}
}
4、客户端代码：
package com.test3;
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.Scanner;
public class AClient {
private Selector selector;
private SocketChannel socketChannel;
private String hostIp;
private int hostPort;
public AClient(String hostIp,int hostPort)throws Exception{
this.hostIp=hostIp;
this.hostPort=hostPort;
init();
}
public void init()throws Exception{
socketChannel=SocketChannel.open(new InetSocketAddress(hostIp,hostPort));
socketChannel.configureBlocking(false);
//打开并注册选择器信道、
selector= Selector.open();
socketChannel.register(selector,SelectionKey.OP_READ);
//启动读取线程
new TcpClientReadThread(selector);
}
/**
*发送字符串到服务器
*/
public void sendMsg(String msgg)throws Exception{
ByteBuffer writeBuffer = ByteBuffer.wrap(msgg.getBytes("UTF-8"));
socketChannel.write(writeBuffer);
}
static AClient aClient;
static boolean mFlag=true;
public static void main(String[]args)throws Exception{
aClient=new AClient("127.0.0.1",9999);
new Thread(){
@Override
public void run() {
try {
aClient.sendMsg("客户端======");
while (mFlag){
Scanner sc = new Scanner(System.in);
String next = sc.next();
aClient.sendMsg(next);
}
}catch (Exception e){
mFlag=false;
e.printStackTrace();
}
}
}.start();
}
}