ByteToLongDecoder:
public class ByteToLongDecoder extends ByteToMessageDecoder {
@Override
protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {
System.out.println("ByteToLongDecoder decode 被调用");
//因为 long 8个字节, 需要判断有8个字节，才能读取一个long
if(in.readableBytes() >= 8) {
out.add(in.readLong());
}
}
}
long:
public class LongToByteEncoder extends MessageToByteEncoder<Long> {
@Override
protected void encode(ChannelHandlerContext ctx, Long msg, ByteBuf out) throws Exception {
System.out.println("LongToByteEncoder encode被调用");
System.out.println("msg=" + msg);
out.writeLong(msg);
}
}
netty client:
public class NettyClient {
public static void main(String[] args) throws Exception {
EventLoopGroup group = new NioEventLoopGroup();
try {
Bootstrap bootstrap = new Bootstrap();
bootstrap.group(group).channel(NioSocketChannel.class)
.handler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel ch) throws Exception {
ChannelPipeline pipeline = ch.pipeline();
//pipeline.addLast(new StringEncoder());
//pipeline.addLast(new ObjectEncoder());
pipeline.addLast(new LongToByteEncoder());
pipeline.addLast(new ByteToLongDecoder());
pipeline.addLast(new NettyClientHandler());
}
});
System.out.println("netty client start。。");
ChannelFuture channelFuture = bootstrap.connect("127.0.0.1", 9000).sync();
channelFuture.channel().closeFuture().sync();
} finally {
group.shutdownGracefully();
}
}
}
public class NettyClientHandler extends ChannelInboundHandlerAdapter {
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
System.out.println("收到服务器消息:" + msg);
}
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
System.out.println("MyClientHandler发送数据");
//ctx.writeAndFlush("测试String编解码");
//测试对象编解码
//ctx.writeAndFlush(new User(1,"zhuge"));
//测试自定义Long数据编解码器
ctx.writeAndFlush(1000L);
}
}
public class NettyServer {
public static void main(String[] args) throws Exception {
EventLoopGroup bossGroup = new NioEventLoopGroup(1);
EventLoopGroup workerGroup = new NioEventLoopGroup();
try {
ServerBootstrap serverBootstrap = new ServerBootstrap();
serverBootstrap.group(bossGroup, workerGroup)
.channel(NioServerSocketChannel.class)
.childHandler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel ch) throws Exception {
ChannelPipeline pipeline = ch.pipeline();
//pipeline.addLast(new StringDecoder());
//pipeline.addLast(new ObjectDecoder(Integer.MAX_VALUE, ClassResolvers.cacheDisabled(null)));
pipeline.addLast(new ByteToLongDecoder());
pipeline.addLast(new LongToByteEncoder());
pipeline.addLast(new NettyServerHandler());
}
});
System.out.println("netty server start。。");
ChannelFuture channelFuture = serverBootstrap.bind(9000).sync();
channelFuture.channel().closeFuture().sync();
} finally {
bossGroup.shutdownGracefully();
workerGroup.shutdownGracefully();
}
}
}
netty 程序：
public class NettyServerHandler extends ChannelInboundHandlerAdapter {
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
//System.out.println("从客户端读取到String：" + msg.toString());
//System.out.println("从客户端读取到Object：" + ((User)msg).toString());
System.out.println("从客户端读取到Long：" + (Long)msg);
//给客户端发回一个long数据
ctx.writeAndFlush(2000L);
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
cause.printStackTrace();
ctx.close();
}
}
user 方法：
package com.tuling.netty.codec;
import java.io.Serializable;
public class User implements Serializable {
private int id;
private String name;
public User(){}
public User(int id, String name) {
super();
this.id = id;
this.name = name;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", name='" + name + '\'' +
'}';
}
}
直接buffer:
public class DirectMemoryOOM {
private static final int _1MB = 1024 * 1024;
public static void main(String[] args) throws IllegalAccessException {
//通过反射获取Unsafe类并通过其分配直接内存
Field unsafeField = Unsafe.class.getDeclaredFields()[0];
unsafeField.setAccessible(true);
Unsafe unsafe = (Unsafe) unsafeField.get(null);
while (true) {
unsafe.allocateMemory(_1MB);
}
}
}
heartbeat:
public class HeartBeatClient {
public static void main(String[] args) throws Exception {
EventLoopGroup eventLoopGroup = new NioEventLoopGroup();
try {
Bootstrap bootstrap = new Bootstrap();
bootstrap.group(eventLoopGroup).channel(NioSocketChannel.class)
.handler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel ch) throws Exception {
ChannelPipeline pipeline = ch.pipeline();
pipeline.addLast("decoder", new StringDecoder());
pipeline.addLast("encoder", new StringEncoder());
pipeline.addLast(new HeartBeatClientHandler());
}
});
System.out.println("netty client start。。");
Channel channel = bootstrap.connect("127.0.0.1", 9000).sync().channel();
String text = "Heartbeat Packet";
Random random = new Random();
while (channel.isActive()) {
int num = random.nextInt(10);
Thread.sleep(2 * 1000);
channel.writeAndFlush(text);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
eventLoopGroup.shutdownGracefully();
}
}
static class HeartBeatClientHandler extends SimpleChannelInboundHandler<String> {
@Override
protected void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception {
System.out.println(" client received :" + msg);
if (msg != null && msg.equals("idle close")) {
System.out.println(" 服务端关闭连接，客户端也关闭");
ctx.channel().closeFuture();
}
}
}
heartbeat server:
public class HeartBeatServer {
public static void main(String[] args) throws Exception {
EventLoopGroup boss = new NioEventLoopGroup();
EventLoopGroup worker = new NioEventLoopGroup();
try {
ServerBootstrap bootstrap = new ServerBootstrap();
bootstrap.group(boss, worker)
.channel(NioServerSocketChannel.class)
.childHandler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel ch) throws Exception {
ChannelPipeline pipeline = ch.pipeline();
pipeline.addLast("decoder", new StringDecoder());
pipeline.addLast("encoder", new StringEncoder());
//IdleStateHandler的readerIdleTime参数指定超过3秒还没收到客户端的连接，
//会触发IdleStateEvent事件并且交给下一个handler处理，下一个handler必须
//实现userEventTriggered方法处理对应事件
pipeline.addLast(new IdleStateHandler(3, 0, 0, TimeUnit.SECONDS));
pipeline.addLast(new HeartBeatServerHandler());
}
});
System.out.println("netty server start。。");
ChannelFuture future = bootstrap.bind(9000).sync();
future.channel().closeFuture().sync();
} catch (Exception e) {
e.printStackTrace();
} finally {
worker.shutdownGracefully();
boss.shutdownGracefully();
}
}
}
HeartBeatServerHander :
public class HeartBeatServerHandler extends SimpleChannelInboundHandler<String> {
int readIdleTimes = 0;
@Override
protected void channelRead0(ChannelHandlerContext ctx, String s) throws Exception {
System.out.println(" ====== > [server] message received : " + s);
if ("Heartbeat Packet".equals(s)) {
ctx.channel().writeAndFlush("ok");
} else {
System.out.println(" 其他信息处理 ... ");
}
}
@Override
public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
IdleStateEvent event = (IdleStateEvent) evt;
String eventType = null;
switch (event.state()) {
case READER_IDLE:
eventType = "读空闲";
readIdleTimes++; // 读空闲的计数加1
break;
case WRITER_IDLE:
eventType = "写空闲";
// 不处理
break;
case ALL_IDLE:
eventType = "读写空闲";
// 不处理
break;
}
System.out.println(ctx.channel().remoteAddress() + "超时事件：" + eventType);
if (readIdleTimes > 3) {
System.out.println(" [server]读空闲超过3次，关闭连接，释放更多资源");
ctx.channel().writeAndFlush("idle close");
ctx.channel().close();
}
}
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
System.err.println("=== " + ctx.channel().remoteAddress() + " is active ===");
}
}
splitpacket:
public class MyClient {
public static void main(String[] args) throws Exception{
EventLoopGroup group = new NioEventLoopGroup();
try {
Bootstrap bootstrap = new Bootstrap();
bootstrap.group(group).channel(NioSocketChannel.class)
.handler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel ch) throws Exception {
ChannelPipeline pipeline = ch.pipeline();
pipeline.addLast(new MyMessageEncoder());
pipeline.addLast(new MyClientHandler());
}
});
System.out.println("netty client start。。");
ChannelFuture channelFuture = bootstrap.connect("127.0.0.1", 9000).sync();
channelFuture.channel().closeFuture().sync();
}finally {
group.shutdownGracefully();
}
}
}
public class MyClientHandler extends SimpleChannelInboundHandler<MyMessageProtocol> {
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
for(int i = 0; i< 200; i++) {
String msg = "你好，我是张三！";
//创建协议包对象
MyMessageProtocol messageProtocol = new MyMessageProtocol();
messageProtocol.setLen(msg.getBytes(CharsetUtil.UTF_8).length);
messageProtocol.setContent(msg.getBytes(CharsetUtil.UTF_8));
ctx.writeAndFlush(messageProtocol);
}
}
@Override
protected void channelRead0(ChannelHandlerContext ctx, MyMessageProtocol msg) throws Exception {
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
cause.printStackTrace();
ctx.close();
}
}
public class MyMessageDecoder extends ByteToMessageDecoder {
int length = 0;
@Override
protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {
System.out.println();
System.out.println("MyMessageDecoder decode 被调用");
//需要将得到二进制字节码-> MyMessageProtocol 数据包(对象)
System.out.println(in);
if(in.readableBytes() >= 4) {
if (length == 0){
length = in.readInt();
}
if (in.readableBytes() < length) {
System.out.println("当前可读数据不够，继续等待。。");
return;
}
byte[] content = new byte[length];
if (in.readableBytes() >= length){
in.readBytes(content);
//封装成MyMessageProtocol对象，传递到下一个handler业务处理
MyMessageProtocol messageProtocol = new MyMessageProtocol();
messageProtocol.setLen(length);
messageProtocol.setContent(content);
out.add(messageProtocol);
}
length = 0;
}
}
}
public class MyMessageEncoder extends MessageToByteEncoder<MyMessageProtocol> {
@Override
protected void encode(ChannelHandlerContext ctx, MyMessageProtocol msg, ByteBuf out) throws Exception {
System.out.println("MyMessageEncoder encode 方法被调用");
out.writeInt(msg.getLen());
out.writeBytes(msg.getContent());
}
}
/**
* 自定义协议包
*/
public class MyMessageProtocol {
//定义一次发送包体长度
private int len;
//一次发送包体内容
private byte[] content;
public int getLen() {
return len;
}
public void setLen(int len) {
this.len = len;
}
public byte[] getContent() {
return content;
}
public void setContent(byte[] content) {
this.content = content;
}
}
public class MyServer {
public static void main(String[] args) throws Exception {
EventLoopGroup bossGroup = new NioEventLoopGroup(1);
EventLoopGroup workerGroup = new NioEventLoopGroup();
try {
ServerBootstrap serverBootstrap = new ServerBootstrap();
serverBootstrap.group(bossGroup, workerGroup)
.channel(NioServerSocketChannel.class)
.childHandler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel ch) throws Exception {
ChannelPipeline pipeline = ch.pipeline();
pipeline.addLast(new MyMessageDecoder());
pipeline.addLast(new MyServerHandler());
}
});
System.out.println("netty server start。。");
ChannelFuture channelFuture = serverBootstrap.bind(9000).sync();
channelFuture.channel().closeFuture().sync();
} finally {
bossGroup.shutdownGracefully();
workerGroup.shutdownGracefully();
}
}
}
public class MyServerHandler extends SimpleChannelInboundHandler<MyMessageProtocol> {
private int count;
@Override
protected void channelRead0(ChannelHandlerContext ctx, MyMessageProtocol msg) throws Exception {
System.out.println("====服务端接收到消息如下====");
System.out.println("长度=" + msg.getLen());
System.out.println("内容=" + new String(msg.getContent(), CharsetUtil.UTF_8));
System.out.println("服务端接收到消息包数量=" + (++this.count));
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
cause.printStackTrace();
ctx.close();
}
}
