Java教程
JAVA Nio demo
本文主要是介绍JAVA Nio demo，对大家解决编程问题具有一定的参考价值，需要的程序猿们随着小编来一起学习吧！
package com.network;
import java.io.EOFException;
import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.nio.ByteBuffer;
import java.nio.channels.*;
import java.util.Iterator;
import java.util.concurrent.ConcurrentLinkedDeque;
import java.util.concurrent.atomic.AtomicBoolean;
public class NioNetwork {
public static Selector readSelector;
public static Selector writeSelector;
public static final int RECEIVE_BUFFER_SIZE = 128;
public static final int SEND_BUFFER_SIZE = 128;
public static void main(String[] args) throws IOException {
ServerSocketChannel serverSocket = ServerSocketChannel.open();
serverSocket.socket().bind(new InetSocketAddress(8899));
serverSocket.configureBlocking(false);
readSelector = Selector.open();
writeSelector = Selector.open();
new Thread(() -> {
for (;;){
try {
int select = readSelector.selectNow();
if( select > 0 ){
Iterator<SelectionKey> it = readSelector.selectedKeys().iterator();
while (it.hasNext()){
SelectionKey sk = it.next();
it.remove();
if( sk.isValid() ){
Handler handler = (Handler)sk.attachment();
try {
handler.handle();
} catch (IOException e) {
handler.onFailure(e);
}
}
}
}
} catch (IOException e) {
e.printStackTrace();
}
}
}).start();
new Thread(() -> {
for (;;){
try {
int select = writeSelector.selectNow();
if( select > 0 ){
Iterator<SelectionKey> it = writeSelector.selectedKeys().iterator();
while (it.hasNext()){
SelectionKey sk = it.next();
it.remove();
if( sk.isValid() ){
Handler handler = (Handler)sk.attachment();
try {
handler.handle();
} catch (IOException e) {
handler.onFailure(e);
}
}else{
System.out.println("invalid sk");
}
}
}
} catch (IOException e) {
e.printStackTrace();
}
}
}).start();
while (true){
SocketChannel clientChannel = serverSocket.accept();
if(clientChannel != null){
System.out.println("accept ....");
clientChannel.configureBlocking(false);
clientChannel.socket().setReceiveBufferSize(RECEIVE_BUFFER_SIZE);
clientChannel.socket().setSendBufferSize(SEND_BUFFER_SIZE);
NioChannel nioChannel = new NioChannel(clientChannel);
Reader reader = new Reader(nioChannel);
Writer writer = new Writer(nioChannel);
nioChannel.setReader(reader);
nioChannel.setWriter(writer);
SelectionKey selectionWriteKey2 = clientChannel.register(writeSelector, SelectionKey.OP_WRITE, writer);
writer.setSk(selectionWriteKey2);
SelectionKey selectionReadKey1 = clientChannel.register(readSelector, SelectionKey.OP_READ, reader);
reader.setSk(selectionReadKey1);
readSelector.wakeup();
}
}
}
}
class NioChannel{
private SocketChannel socketChannel;
private Reader reader;
private Writer writer;
public NioChannel( SocketChannel channel) {
this.socketChannel = channel;
}
public SocketChannel getChannel() {
return socketChannel;
}
public Reader getReader() {
return reader;
}
public void setReader(Reader reader) {
this.reader = reader;
}
public Writer getWriter() {
return writer;
}
public void setWriter(Writer writer) {
this.writer = writer;
}
}
class Reader extends Handler{
private ByteBuffer buffer;
private Packet packet ;
public String getName(){
return "Reader";
}
public Reader(NioChannel channel) {
super(channel);
interestOps = SelectionKey.OP_READ;
}
@Override
protected String getMsg() {
return "From Read;";
}
@Override
public void handle() throws IOException {
if(buffer == null){
buffer = ByteBuffer.allocate(NioNetwork.RECEIVE_BUFFER_SIZE);
}
int readBytes = getChannel().read(buffer);
if( readBytes <= 0 ){
if( readBytes == -1 ){
throw new EOFException("remote socket closed");
}
return;
}
buffer.flip();
while( buffer.hasRemaining() ){
if( packet == null ){
packet = new Packet();
}
Boolean complete = packet.readFrom(buffer);
if( complete ){
doHandle(packet);
packet = null;
}else{
break;
}
}
compactOrClear(buffer);
}
private void doHandle( Packet packet ) throws ClosedChannelException {
Packet packet1 = new Packet();
packet1.setType(Packet.Type.RESPONSE);
getNioChannel().getWriter().write(packet1);
}
}
class Writer extends Handler{
private ConcurrentLinkedDeque<Packet> writeQueue = new ConcurrentLinkedDeque<>();
private ByteBuffer outputBuffer;
private Packet currentPacket;
private AtomicBoolean scheduled = new AtomicBoolean(false);
public String getName(){
return "Writer";
}
public Writer(NioChannel channel) {
super(channel);
interestOps = SelectionKey.OP_WRITE;
}
@Override
protected String getMsg() {
return "From Write;";
}
public void write( Packet packet) throws ClosedChannelException {
writeQueue.offer( packet );
schedule();
}
private void schedule() throws ClosedChannelException {
if( scheduled.get()){
return;
}
if( !scheduled.compareAndSet(false, true)){
return;
}
//绑定读就绪
getNioChannel().getChannel().register(NioNetwork.writeSelector, getInterestOps(),this );
}
@Override
public void handle() throws IOException {
if( outputBuffer == null ){
outputBuffer = ByteBuffer.allocate(NioNetwork.SEND_BUFFER_SIZE);
}
//do something
if( currentPacket == null ){
currentPacket = writeQueue.poll();
}
while (currentPacket != null ){
if ( !onWrite(currentPacket, outputBuffer)){
return ;
}
currentPacket = writeQueue.poll();
}
if( outputBuffer !=null && outputBuffer.position() > 0){
outputBuffer.flip();
getChannel().write(outputBuffer);
compactOrClear(outputBuffer);
}else{
int interestOps = getSk().interestOps();
if( (interestOps & getInterestOps()) != 0 ){
getSk().interestOps(interestOps & ~getInterestOps());
}
}
}
private boolean onWrite( Packet packet , ByteBuffer dst ){
return packet.writeTo(dst);
}
}
class Handler{
private SocketChannel channel;
private NioChannel nioChannel;
private ByteBuffer buffer;
private SelectionKey sk;
protected int interestOps;
protected String getName(){
return "";
}
public Handler(NioChannel channel) {
this.channel = channel.getChannel();
this.nioChannel = channel;
}
public NioChannel getNioChannel() {
return nioChannel;
}
protected String getMsg(){
return "";
};
public void handle() throws IOException {
if( buffer == null ){
buffer = ByteBuffer.allocate(128);
}
int readBytes = channel.read(buffer);
if( readBytes <=0 ){
if (readBytes == -1) {
throw new EOFException("Remote socket closed!");
}
return;
}
buffer.flip();
System.out.println(getName()+"buf:"+buffer.getChar());
channel.write(buffer);
buffer.clear();
}
public SocketChannel getChannel() {
return channel;
}
public void onFailure( Throwable cause ){
Socket socket = channel.socket();
try {
cause.printStackTrace();
socket.close();
System.out.println("Error client Closed :"+cause.getMessage());
} catch (IOException e) {
e.printStackTrace();
}
}
public SelectionKey getSk() {
return sk;
}
public void setSk(SelectionKey sk) {
this.sk = sk;
}
public int getInterestOps() {
return interestOps;
}
public void compactOrClear(ByteBuffer bb) {
if (bb.hasRemaining()) {
bb.compact();
} else {
bb.clear();
}
}
}
Client:
package com.network;
import sun.nio.ch.DirectBuffer;
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.concurrent.ConcurrentLinkedQueue;
public class ClientNetwork {
public static Selector selector;
private static volatile ClientNetwork instance;
static {
try {
selector = Selector.open();
} catch (IOException e) {
e.printStackTrace();
}
}
private void ClientNetwork(){
}
public static ClientNetwork getInstance() throws IOException {
if( instance == null ){
synchronized (ClientNetwork.class){
if( instance == null ){
instance = new ClientNetwork();
}
}
}
return instance;
}
private ByteBuffer readByte;
private ByteBuffer writeByte;
private ConcurrentLinkedQueue<Packet> sendQueue = new ConcurrentLinkedQueue<>();
public ClientNetwork() throws IOException {
SocketChannel socketChannel = SocketChannel.open();
socketChannel.connect(new InetSocketAddress(8899));
SelectionKey sk = socketChannel.register(selector, SelectionKey.OP_READ | SelectionKey.OP_WRITE);
sk.attach( this );
new Thread(() -> {
try {
int select = selector.select(1000);
if( select > 0 ){
Iterator<SelectionKey> iterator = selector.selectedKeys().iterator();
while (iterator.hasNext()){
SelectionKey next = iterator.next();
iterator.remove();
if( next.isValid() ) {
handler(next);
}
}
}
} catch (IOException e) {
e.printStackTrace();
}
}).run();
}
public void handler(SelectionKey sk ){
if(sk.isReadable()){
read();
}else{
send( new Packet() );
}
}
public boolean send( Packet packet ){
sendQueue.offer(packet);
return true;
}
public Packet read(){
return null;
}
public static void main(String[] args) throws IOException, InterruptedException {
SocketChannel socketChannel = SocketChannel.open();
socketChannel.connect(new InetSocketAddress(8899));
socketChannel.configureBlocking(false);
Packet packet = new Packet();
ByteBuffer byteBuffer = ByteBuffer.allocate(128);
boolean writeOk = packet.writeTo(byteBuffer);
if(!writeOk){
System.out.println("writeFailed");
}
byteBuffer.flip();
socketChannel.write(byteBuffer);
byteBuffer.flip();
for(;;){
if(socketChannel.read(byteBuffer) > 0){
byteBuffer.rewind();
Packet packet1 = new Packet();
packet1.readFrom(byteBuffer);
System.out.println(packet1.getType());
break;
}
}
}
}
这篇关于JAVA Nio demo的文章就介绍到这儿，希望我们推荐的文章对大家有所帮助，也希望大家多多支持为之网！
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