Netty的AttributeMap

Netty的AttributeMap

AttributeMap接口

public interface AttributeMap {
<T> Attribute<T> attr(AttributeKey<T> key);
}

AttributeMap接口只有一个attr()方法，接收一个AttributeKey类型的key，返回一个Attribute类型的value。按照Javadoc，AttributeMap实现必须是线程安全的。所有的Channel和ChannelHandlerContext实现了AttributeMap接口

简单应用：

public class AttributeMapID {
public static final AttributeKey<ChannelID> Channel_ID = AttributeKey.valueOf("netty.channel");
}

public class ClienHandler extends ChannelInboundHandlerAdapter{
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
Attribute<ChannelID> attribute =
ctx.attr(Channel_ID);
ChannelID channelID = attribute.get();
if (channelID==null) {
ChannelID id = new ChannelID("link",new Date());
channelID = attribute.setIfAbsent(id);
} else {
System.out.println("channelActive attributeMap 中是有值的");
System.out.println(channelID.getName() + "=======" + channelID.getDate());
}
System.out.println("HelloWorldC0ientHandler Active");
ctx.fireChannelActive();
}
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
Attribute<ChannelID> attribute =
ctx.attr(Channel_ID);
ChannelID channelID = attribute.get();
if (channelID==null) {
ChannelID id = new ChannelID("link",new Date());
channelID = attribute.setIfAbsent(id);
} else {
System.out.println("channelActive attributeMap 中是有值的");
System.out.println(channelID.getName() + "=======" + channelID.getDate());
}
System.out.println("HelloWorldClientHandler read Message:" + msg);
ctx.fireChannelRead(msg);
}
}

public class Server {
int port;
public Server(int port) {
this.port = port;
start();
}
public void start() {
EventLoopGroup bossGroup = new NioEventLoopGroup(1);
EventLoopGroup workerGroup = new NioEventLoopGroup();
try {
ServerBootstrap sbs = new ServerBootstrap().group(bossGroup,workerGroup).channel(NioServerSocketChannel.class).localAddress(new InetSocketAddress(port))
.childHandler(new ChannelInitializer<SocketChannel>() {
protected void initChannel(SocketChannel ch) throws Exception {
ch.pipeline().addLast("decoder", new StringDecoder());
ch.pipeline().addLast("encoder", new StringEncoder());
ch.pipeline().addLast(new ServerHandler());
};
}).option(ChannelOption.SO_BACKLOG, 128)
.childOption(ChannelOption.SO_KEEPALIVE, true);
// 绑定端口，开始接收进来的连接

ChannelFuture future = sbs.bind(port).sync();
System.out.println("Server start listen at " + port );
future.channel().closeFuture().sync();
} catch (Exception e) {
bossGroup.shutdownGracefully();
workerGroup.shutdownGracefully();
}
}
public static void main(String[] args) {
Server server = new Server(7788);
}
}

public class ServerHandler extends ChannelInboundHandlerAdapter{
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
System.out.println("server channelRead..");
System.out.println(ctx.channel().remoteAddress()+"->Server :"+ msg.toString());
ctx.write("server write"+msg);
ctx.flush();
}
}

public class Client {
String host;
int port;
public Client(String host,int port) throws InterruptedException {
// TODO Auto-generated constructor stub
this.host = host;
this.port =port;
connect();
}
public void connect() throws InterruptedException {
EventLoopGroup group = new NioEventLoopGroup();
try {
Bootstrap b = new Bootstrap();
b.group(group)
.channel(NioSocketChannel.class)
.option(ChannelOption.TCP_NODELAY, true)
.handler(new ChannelInitializer<SocketChannel>() {
@Override
public void initChannel(SocketChannel ch) throws Exception {
ChannelPipeline p = ch.pipeline();
p.addLast("decoder", new StringDecoder());
p.addLast("encoder", new StringEncoder());
p.addLast(new ClienHandler());
}
});
ChannelFuture future = b.connect(host,port).sync();
future.channel().writeAndFlush("hello Netty,Test attributeMap");
future.channel().closeFuture().sync();
} finally {
group.shutdownGracefully();
}
}
public static void main(String[] args) throws InterruptedException {
Client client = new Client("127.0.0.1", 7788);
}
}

public class ChannelID {
String name;
Date date;
public ChannelID(String name,Date date) {
// TODO Auto-generated constructor stub
this.date = date;
this.name = name;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Date getDate() {
return date;
}
public void setDate(Date date) {
this.date = date;
}
}

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