因工作中需要给第三方屏幕厂家下发广告，音频，图片等内容，对方提供TCP接口于是我使用Netty长链接进行数据传输
1.添加依赖
<!-- netty依赖-->
<dependency>
<groupId>io.netty</groupId>
<artifactId>netty-all</artifactId>
</dependency> 2.创建Netty服务
@Slf4j
@Component
public class NettyServer {
public void start(InetSocketAddress address) {
//配置服务端的NIO线程组
EventLoopGroup bossGroup = new NioEventLoopGroup();
EventLoopGroup workerGroup = new NioEventLoopGroup();
try {
// 绑定线程池,编码解码
//服务端接受连接的队列长度，如果队列已满，客户端连接将被拒绝
ServerBootstrap bootstrap = new ServerBootstrap()
.group(bossGroup, workerGroup)
// 指定Channel
.channel(NioServerSocketChannel.class)
//使用指定的端口设置套接字地址
.localAddress(address)
//使用自定义处理类
.childHandler(new NettyServerChannelInitializer())
//服务端可连接队列数,对应TCP/IP协议listen函数中backlog参数
.option(ChannelOption.SO_BACKLOG, 128)
//保持长连接，2小时无数据激活心跳机制
.childOption(ChannelOption.SO_KEEPALIVE, true)
//将小的数据包包装成更大的帧进行传送，提高网络的负载
.childOption(ChannelOption.TCP_NODELAY, true);
// 绑定端口，开始接收进来的连接
ChannelFuture future = bootstrap.bind(address).sync();
if (future.isSuccess()) {
log.info("netty服务器开始监听端口：{}",address.getPort());
}
//关闭channel和块，直到它被关闭
future.channel().closeFuture().sync();
} catch (Exception e) {
e.printStackTrace();
bossGroup.shutdownGracefully();
workerGroup.shutdownGracefully();
}
}
}3.创建Socket配置类（也可以直接在步骤2中写死）
1.在配置文件中
socket:
# 监听端口 8090
port: 8090
#ip地址
host: 0.0.0.0
# host: 192.168.31.2
@Setter
@Getter
@ToString
@Component
@Configuration
@PropertySource("classpath:application.yml")
@ConfigurationProperties(prefix = "socket")
public class SocketProperties {
private Integer port;
private String host;
}4.在springboot 启动类中启用Netty服务
@SpringBootApplication
public class Application implements CommandLineRunner {
public static void main(String[] args) {
SpringApplication application = new SpringApplication(Application.class);
application.setApplicationStartup(new BufferingApplicationStartup(2048));
application.run(args);
}
@Resource
private NettyServer nettyServer;
@Resource
private SocketProperties socketProperties;
@Override
public void run(String... args) {
InetSocketAddress address = new InetSocketAddress(socketProperties.getHost(),socketProperties.getPort());
nettyServer.start(address);
}
}5.创建字符解析器，解析收到的消息
/**
* 功能描述: 服务端初始化，客户端与服务器端连接一旦创建，这个类中方法就会被回调，设置出站编码器和入站解码器
*
*/
public class NettyServerChannelInitializer extends ChannelInitializer<SocketChannel> {
@Override
protected void initChannel(SocketChannel socketChannel) throws Exception {
ChannelPipeline pipeline = socketChannel.pipeline();
//接收消息格式,使用自定义解析数据格式
// pipeline.addLast("decoder",new MyDecoder());
//发送消息格式，使用自定义解析数据格式
// pipeline.addLast("encoder",new MyEncoder());
pipeline.addLast(new StringEncoder(CharsetUtil.UTF_8));
//针对客户端，如果在1分钟时没有想服务端发送写心跳(ALL)，则主动断开
//如果是读空闲或者写空闲，不处理,这里根据自己业务考虑使用
pipeline.addLast(new IdleStateHandler(0,0,90, TimeUnit.SECONDS));
//自定义的空闲检测
pipeline.addLast(new NettyServerHandler());
}
}6.创建Handler 类处理消息
/**
* 功能描述: netty服务端处理类
*/
@Slf4j
@Component
public class NettyServerHandler extends ChannelInboundHandlerAdapter {
/**
* 功能描述: 有客户端连接服务器会触发此函数
*
* @param ctx 通道
* @return void
*/
@Override
public void channelActive(ChannelHandlerContext ctx) {
InetSocketAddress insocket = (InetSocketAddress) ctx.channel().remoteAddress();
String clientIp = insocket.getAddress().getHostAddress();
int clientPort = insocket.getPort();
//获取连接通道唯一标识
ChannelId channelId = ctx.channel().id();
//如果map中不包含此连接，就保存连接
if (ChannelMap.getChannelMap().containsKey(channelId)) {
log.info("客户端:{},是连接状态，连接通道数量:{} ", channelId, ChannelMap.getChannelMap().size());
} else {
//保存连接
ChannelMap.addChannel(channelId, ctx.channel());
log.info("客户端:{},连接netty服务器[IP:{}-->PORT:{}]", channelId, clientIp, clientPort);
log.info("连接通道数量: {}", ChannelMap.getChannelMap().size());
}
}
/**
* 功能描述: 有客户端终止连接服务器会触发此函数
* @param ctx 通道处理程序上下文
* @return void
*/
@Override
public void channelInactive(ChannelHandlerContext ctx) {
InetSocketAddress inSocket = (InetSocketAddress) ctx.channel().remoteAddress();
String clientIp = inSocket.getAddress().getHostAddress();
ChannelId channelId = ctx.channel().id();
//包含此客户端才去删除
if (ChannelMap.getChannelMap().containsKey(channelId)) {
//删除连接
ChannelMap.getChannelMap().remove(channelId);
log.info("客户端:{},断开netty服务器[IP:{}-->PORT:{}]", channelId, clientIp, inSocket.getPort());
log.info("连接通道数量: " + ChannelMap.getChannelMap().size());
}
}
@Transactional
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
ByteBuf buf = (ByteBuf) msg;
ByteBuf rebuf = Unpooled.buffer();
RedisUtils.setChannelId(ctx.channel().id().toString(), ctx.channel().id());
// 读取帧头标识
byte frameHeader = buf.readByte();
if (frameHeader != 0x7E) {
byte[] data = ByteBufUtil.getBytes(buf);
String hex = bytesToHex(data);
buf.release();
String content = ((ByteBuf) msg).toString(Charset.defaultCharset());
} // 读取消息帧类型
else {
byte messageType = buf.readByte();
// 读取帧尾标识
if (buf.isReadable()) {
// 读取校验值
byte checksum = buf.readByte();
byte frameTail = buf.readByte();
}
}
buf.release();
}
/**
* 功能描述: 服务端给客户端发送消息
*
* @param channelId 连接通道唯一id
* @param msg 需要发送的消息内容
* @return void
*/
public void channelWrite(ChannelId channelId, Object msg) throws Exception {
Channel channel = ChannelMap.getChannelMap().get(channelId);
if (channel == null) {
log.info("通道:{},不存在", channelId);
return;
}
if (msg == null || msg == "") {
log.info("服务端响应空的消息");
return;
}
//将客户端的信息直接返回写入ctx
channel.write(msg);
//刷新缓存区
channel.flush();
}
@Override
public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
String socketString = ctx.channel().remoteAddress().toString();
if (evt instanceof IdleStateEvent) {
IdleStateEvent event = (IdleStateEvent) evt;
if (event.state() == IdleState.READER_IDLE) {
log.info("Client:{},READER_IDLE 读超时", socketString);
Channel channel = ctx.channel();
ChannelId id = channel.id();
// 超时未收到心跳包，更新设备状态为离线
// todo 更新设备状态
ctx.disconnect();
ChannelMap.removeChannelByName(id);
} else if (event.state() == IdleState.WRITER_IDLE) {
log.info("Client:{}, WRITER_IDLE 写超时", socketString);
ctx.disconnect();
Channel channel = ctx.channel();
ChannelId id = channel.id();
ChannelMap.removeChannelByName(id);
} else if (event.state() == IdleState.ALL_IDLE) {
log.info("Client:{},ALL_IDLE 总超时", socketString);
Channel channel = ctx.channel();
ChannelId id = channel.id();
// 超时未收到心跳包，更新设备状态为离线
// todo 更新设备状态
ctx.disconnect();
ChannelMap.removeChannelByName(id);
}
}
}
/**
* 功能描述: 发生异常会触发此函数
*
* @param ctx 通道处理程序上下文
* @param cause 异常
* @return void
*/
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
ctx.close();
log.info("{}:发生了错误,此连接被关闭。此时连通数量:{}", ctx.channel().id(), ChannelMap.getChannelMap().size());
}
}ChannelMap类
/**
* 功能描述: 管理通道Map类
*
*/
public class ChannelMap {
/**
* 管理一个全局map，保存连接进服务端的通道数量
*/
private static final ConcurrentHashMap<ChannelId, Channel> CHANNEL_MAP = new ConcurrentHashMap<>(128);
public static ConcurrentHashMap<ChannelId, Channel> getChannelMap() {
return CHANNEL_MAP;
}
/**
* 获取指定name的channel
*/
public static Channel getChannelByName(ChannelId channelId){
if(CollectionUtils.isEmpty(CHANNEL_MAP)){
return null;
}
return CHANNEL_MAP.get(channelId);
}
/**
* 将通道中的消息推送到每一个客户端
*/
public static boolean pushNewsToAllClient(String obj){
if(CollectionUtils.isEmpty(CHANNEL_MAP)){
return false;
}
for(ChannelId channelId: CHANNEL_MAP.keySet()) {
Channel channel = CHANNEL_MAP.get(channelId);
channel.writeAndFlush(new TextWebSocketFrame(obj));
}
return true;
}
/**
* 将channel和对应的name添加到ConcurrentHashMap
*/
public static void addChannel(ChannelId channelId,Channel channel){
CHANNEL_MAP.put(channelId,channel);
}
/**
* 移除掉name对应的channel
*/
public static boolean removeChannelByName(ChannelId channelId){
if(CHANNEL_MAP.containsKey(channelId)){
CHANNEL_MAP.remove(channelId);
return true;
}
return false;
}
}