Spring Boot+Netty+Websocket實(shí)現(xiàn)后臺(tái)向前端推送信息
netty服務(wù)器
@Component
public class NettyServer {
static final Logger log = LoggerFactory.getLogger(NettyServer.class);
/**
* 端口號(hào)
*/
@Value("${webSocket.netty.port:8888}")
int port;
EventLoopGroup bossGroup;
EventLoopGroup workGroup;
@Autowired
ProjectInitializer nettyInitializer;
@PostConstruct
public void start() throws InterruptedException {
new Thread(() -> {
bossGroup = new NioEventLoopGroup();
workGroup = new NioEventLoopGroup();
ServerBootstrap bootstrap = new ServerBootstrap();
// bossGroup輔助客戶端的tcp連接請求, workGroup負(fù)責(zé)與客戶端之前的讀寫操作
bootstrap.group(bossGroup, workGroup);
// 設(shè)置NIO類型的channel
bootstrap.channel(NioServerSocketChannel.class);
// 設(shè)置監(jiān)聽端口
bootstrap.localAddress(new InetSocketAddress(port));
// 設(shè)置管道
bootstrap.childHandler(nettyInitializer);
// 配置完成，開始綁定server，通過調(diào)用sync同步方法阻塞直到綁定成功
ChannelFuture channelFuture = null;
try {
channelFuture = bootstrap.bind().sync();
log.info("Server started and listen on:{}", channelFuture.channel().localAddress());
// 對(duì)關(guān)閉通道進(jìn)行監(jiān)聽
channelFuture.channel().closeFuture().sync();
} catch (InterruptedException e) {
e.printStackTrace();
}
}).start();
}
/**
* 釋放資源
*/
@PreDestroy
public void destroy() throws InterruptedException {
if (bossGroup != null) {
bossGroup.shutdownGracefully().sync();
}
if (workGroup != null) {
workGroup.shutdownGracefully().sync();
}
}
}Netty配置
管理全局Channel以及用戶對(duì)應(yīng)的channel（推送消息）
public class NettyConfig {
/**
* 定義全局單利channel組 管理所有channel
*/
private static volatile ChannelGroup channelGroup = null;
/**
* 存放請求ID與channel的對(duì)應(yīng)關(guān)系
*/
private static volatile ConcurrentHashMap<String, Channel> channelMap = null;
/**
* 定義兩把鎖
*/
private static final Object lock1 = new Object();
private static final Object lock2 = new Object();
public static ChannelGroup getChannelGroup() {
if (null == channelGroup) {
synchronized (lock1) {
if (null == channelGroup) {
channelGroup = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);
}
}
}
return channelGroup;
}
public static ConcurrentHashMap<String, Channel> getChannelMap() {
if (null == channelMap) {
synchronized (lock2) {
if (null == channelMap) {
channelMap = new ConcurrentHashMap<>();
}
}
}
return channelMap;
}
public static Channel getChannel(String userId) {
if (null == channelMap) {
return getChannelMap().get(userId);
}
return channelMap.get(userId);
}
}管道配置
@Component
public class ProjectInitializer extends ChannelInitializer<SocketChannel> {
/**
* webSocket協(xié)議名
*/
static final String WEBSOCKET_PROTOCOL = "WebSocket";
/**
* webSocket路徑
*/
@Value("${webSocket.netty.path:/webSocket}")
String webSocketPath;
@Autowired
WebSocketHandler webSocketHandler;
@Override
protected void initChannel(SocketChannel socketChannel) throws Exception {
// 設(shè)置管道
ChannelPipeline pipeline = socketChannel.pipeline();
// 流水線管理通道中的處理程序（Handler），用來處理業(yè)務(wù)
// webSocket協(xié)議本身是基于http協(xié)議的，所以這邊也要使用http編解碼器
pipeline.addLast(new HttpServerCodec());
pipeline.addLast(new ObjectEncoder());
// 以塊的方式來寫的處理器
pipeline.addLast(new ChunkedWriteHandler());
pipeline.addLast(new HttpObjectAggregator(8192));
pipeline.addLast(new WebSocketServerProtocolHandler(webSocketPath, WEBSOCKET_PROTOCOL, true, 65536 * 10));
// 自定義的handler，處理業(yè)務(wù)邏輯
pipeline.addLast(webSocketHandler);
}
}
自定義handler
@Component
@ChannelHandler.Sharable
public class WebSocketHandler extends SimpleChannelInboundHandler<TextWebSocketFrame> {
private static final Logger log = LoggerFactory.getLogger(NettyServer.class);
/**
* 一旦連接，第一個(gè)被執(zhí)行
*/
@Override
public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
log.info("有新的客戶端鏈接：[{}]", ctx.channel().id().asLongText());
// 添加到channelGroup 通道組
NettyConfig.getChannelGroup().add(ctx.channel());
}
/**
* 讀取數(shù)據(jù)
*/
@Override
protected void channelRead0(ChannelHandlerContext ctx, TextWebSocketFrame msg) throws Exception {
log.info("服務(wù)器收到消息：{}", msg.text());
// 獲取用戶ID,關(guān)聯(lián)channel
JSONObject jsonObject = JSONUtil.parseObj(msg.text());
String uid = jsonObject.getStr("uid");
NettyConfig.getChannelMap().put(uid, ctx.channel());
// 將用戶ID作為自定義屬性加入到channel中，方便隨時(shí)channel中獲取用戶ID
AttributeKey<String> key = AttributeKey.valueOf("userId");
ctx.channel().attr(key).setIfAbsent(uid);
// 回復(fù)消息
ctx.channel().writeAndFlush(new TextWebSocketFrame("服務(wù)器收到消息啦"));
}
@Override
public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
log.info("用戶下線了:{}", ctx.channel().id().asLongText());
// 刪除通道
NettyConfig.getChannelGroup().remove(ctx.channel());
removeUserId(ctx);
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
log.info("異常：{}", cause.getMessage());
// 刪除通道
NettyConfig.getChannelGroup().remove(ctx.channel());
removeUserId(ctx);
ctx.close();
}
/**
* 刪除用戶與channel的對(duì)應(yīng)關(guān)系
*/
private void removeUserId(ChannelHandlerContext ctx) {
AttributeKey<String> key = AttributeKey.valueOf("userId");
String userId = ctx.channel().attr(key).get();
NettyConfig.getChannelMap().remove(userId);
}
}
推送消息接口及實(shí)現(xiàn)類
public interface PushMsgService {
/**
* 推送給指定用戶
*/
void pushMsgToOne(String userId, String msg);
/**
* 推送給所有用戶
*/
void pushMsgToAll(String msg);
}
@Service
public class PushMsgServiceImpl implements PushMsgService {
@Override
public void pushMsgToOne(String userId, String msg) {
Channel channel = NettyConfig.getChannel(userId);
if (Objects.isNull(channel)) {
throw new RuntimeException("未連接socket服務(wù)器");
}
channel.writeAndFlush(new TextWebSocketFrame(msg));
}
@Override
public void pushMsgToAll(String msg) {
NettyConfig.getChannelGroup().writeAndFlush(new TextWebSocketFrame(msg));
}
}
測試
鏈接服務(wù)器
發(fā)送消息
調(diào)用接口，往前端推送消息！
OK！
一個(gè)簡單的 netty 小栗子就完成了。
來源：https://blog.csdn.net/weixin_44912855
/article/details/122667977
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