Java 后端通过 WebSocket 向前端推送消息

1、WebSocketConfig 配置类

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.socket.config.annotation.EnableWebSocket;
import org.springframework.web.socket.server.standard.ServerEndpointExporter;

@Configuration
@EnableWebSocket
public class WebSocketConfig {
    @Bean
    public ServerEndpointExporter serverEndpointExporter() {
        return new ServerEndpointExporter();
    }
}

2、WebSocket 消息发送接收

import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;
import org.springframework.util.ObjectUtils;
import javax.websocket.*;
import javax.websocket.server.PathParam;
import javax.websocket.server.ServerEndpoint;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;

@Slf4j
@Component
@ServerEndpoint(value = "/web/{id}")
public class WebSocketProcess {
    /**
     * 持有每个 webSocket 对象，以 key-value 存储到线程安全 ConcurrentHashMap
     */
    private static ConcurrentHashMap<Long, WebSocketProcess> concurrentHashMap = new ConcurrentHashMap<>(16);

    
     Session session;

    
    
       {
        
        .session = session;
        concurrentHashMap.put(id, );
        log.info(, id);
    }

    
    
       {
        
        concurrentHashMap.remove(id);
        log.info(, id);
    }

    
    
       {
        log.info(, id, message);
    }

    
    
       {
        log.error(, error);
    }

    
        Exception {
        
           concurrentHashMap.get(id);
         (!ObjectUtils.isEmpty(webSocketProcess)) {
            
             (webSocketProcess.session.isOpen()) {
                webSocketProcess.session.getBasicRemote().sendText(message);
            }  {
                log.error(, id);
            }
        }  {
            log.error(, id);
        }
    }

    
        Exception {
        log.info(, concurrentHashMap.size());
        Set<Map.Entry<Long, WebSocketProcess>> entries = concurrentHashMap.entrySet();
         (Map.Entry<Long, WebSocketProcess> entry : entries) {
               entry.getKey();
               entry.getValue();
               webSocketProcess.session.isOpen();
             (sessionOpen) {
                webSocketProcess.session.getBasicRemote().sendText(msg);
            }  {
                log.info(, cid);
            }
        }
    }
}