实现推送消息给指定的用户
一、依赖
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<parent>
<artifactId>springboot-demo</artifactId>
<groupId>com.et</groupId>
<version>1.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>netty</artifactId>
<properties>
<maven.compiler.source>8</maven.compiler.source>
<maven.compiler.target>8</maven.compiler.target>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-autoconfigure</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>io.netty</groupId>
<artifactId>netty-all</artifactId>
<version>4.1.87.Final</version>
</dependency>
<dependency>
<groupId>cn.hutool</groupId>
<artifactId>hutool-all</artifactId>
<version>5.6.1</version>
</dependency>
</dependencies>
</project>
二、属性文件和启动类
server:
port: 8088
三、Controller接口
@RestController
@RequestMapping("/push")
public class TestController{
@Autowired
PushMsgService pushMsgService
}
四、PushMsgService
public interface PushMsgService{
//推送给指定用户
void pushMsgToOne(String userId,String msg);
//推送给所有用户
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("未连接socket服务器");
}
channel.writeAndFlush(new TextWebSocketFrame(msg));
}
@Override
public void pushMsgToAll(String msg){
NettyConfig.getChannelGroup().writeAndFlush(new TextWebSocketFrame(msg));
}
}
五、NettyConfig
public class NettyConfig{
//定义全局channel,管理所有的channel
private static volatile ChannelGroup channelGroup = null;
//存放请求ID与channel的对应关系
private static volatile ConcurrentHashMap<String, Channel> channelMap = null;
//定义两把锁
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);
}
}
六、netty server
@Component
public class NettyServer {
static final Logger log = LoggerFactory.getLogger(NettyServer.class);
/**
* 端口号
*/
@Value("${webSocket.netty.port:8889}")
int port;
EventLoopGroup bossGroup;
EventLoopGroup workGroup;
@Autowired
ProjectInitializer nettyInitializer;
@PostConstruct
public void start() throws InterruptedException {
new Thread(() -> {
bossGroup = new NioEventLoopGroup();
workGroup = new NioEventLoopGroup();
ServerBootstrap bootstrap = new ServerBootstrap();
// bossGroup辅助客户端的tcp连接请求, workGroup负责与客户端之前的读写操作
bootstrap.group(bossGroup, workGroup);
// 设置NIO类型的channel
bootstrap.channel(NioServerSocketChannel.class);
// 设置监听端口
bootstrap.localAddress(new InetSocketAddress(port));
// 设置管道
bootstrap.childHandler(nettyInitializer);
// 配置完成,开始绑定server,通过调用sync同步方法阻塞直到绑定成功
ChannelFuture channelFuture = null;
try {
channelFuture = bootstrap.bind().sync();
log.info("Server started and listen on:{}", channelFuture.channel().localAddress());
// 对关闭通道进行监听
channelFuture.channel().closeFuture().sync();
} catch (InterruptedException e) {
e.printStackTrace();
}
}).start();
}
/**
* 释放资源
*/
@PreDestroy
public void destroy() throws InterruptedException {
if (bossGroup != null) {
bossGroup.shutdownGracefully().sync();
}
if (workGroup != null) {
workGroup.shutdownGracefully().sync();
}
}
}
七、ProjectInitializer初始化,设置websocket handler
@Component
public class ProjectInitializer extends ChannelInitializer<SocketChannel> {
/**
* webSocket协议名
*/
static final String WEBSOCKET_PROTOCOL = "WebSocket";
/**
* webSocket路径
*/
@Value("${webSocket.netty.path:/webSocket}")
String webSocketPath;
@Autowired
WebSocketHandler webSocketHandler;
@Override
protected void initChannel(SocketChannel socketChannel) throws Exception {
// 设置管道
ChannelPipeline pipeline = socketChannel.pipeline();
// 流水线管理通道中的处理程序(Handler),用来处理业务
// webSocket协议本身是基于http协议的,所以这边也要使用http编解码器
pipeline.addLast(new HttpServerCodec());
pipeline.addLast(new ObjectEncoder());
// 以块的方式来写的处理器
pipeline.addLast(new ChunkedWriteHandler());
pipeline.addLast(new HttpObjectAggregator(8192));
pipeline.addLast(new WebSocketServerProtocolHandler(webSocketPath, WEBSOCKET_PROTOCOL, true, 65536 * 10));
// 自定义的handler,处理业务逻辑
pipeline.addLast(webSocketHandler);
}
}
八、WebSocketHandler
@Component
@ChannelHandler.Sharable
public class WebSocketHandler extends SimpleChannelInboundHandler<TextWebSocketFrame> {
private static final Logger log = LoggerFactory.getLogger(NettyServer.class);
/**
* 一旦连接,第一个被执行
*/
@Override
public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
log.info("有新的客户端链接:[{}]", ctx.channel().id().asLongText());
// 添加到channelGroup 通道组
NettyConfig.getChannelGroup().add(ctx.channel());
}
/**
* 读取数据
*/
@Override
protected void channelRead0(ChannelHandlerContext ctx, TextWebSocketFrame msg) throws Exception {
log.info("服务器收到消息:{}", msg.text());
// 获取用户ID,关联channel
JSONObject jsonObject = JSONUtil.parseObj(msg.text());
String uid = jsonObject.getStr("uid");
NettyConfig.getChannelMap().put(uid, ctx.channel());
// 将用户ID作为自定义属性加入到channel中,方便随时channel中获取用户ID
AttributeKey<String> key = AttributeKey.valueOf("userId");
ctx.channel().attr(key).setIfAbsent(uid);
// 回复消息
ctx.channel().writeAndFlush(new TextWebSocketFrame("服务器收到消息啦"));
}
@Override
public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
log.info("用户下线了:{}", ctx.channel().id().asLongText());
// 删除通道
NettyConfig.getChannelGroup().remove(ctx.channel());
removeUserId(ctx);
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
log.info("异常:{}", cause.getMessage());
// 删除通道
NettyConfig.getChannelGroup().remove(ctx.channel());
removeUserId(ctx);
ctx.close();
}
/**
* 删除用户与channel的对应关系
*/
private void removeUserId(ChannelHandlerContext ctx) {
AttributeKey<String> key = AttributeKey.valueOf("userId");
String userId = ctx.channel().attr(key).get();
NettyConfig.getChannelMap().remove(userId);
}
}
测试:
postman创建websocket连接 ws://127.0.0.1:8889/webSocket,并发送消息{‘uid’:‘sss’}给服务端
打开浏览器,给用户sss推送消息 http://127.0.0.1:8088/push/sss