kafka + websocket 给前端展示
依赖：
org.apache.kafka
kafka_2.12
2.2.0
org.apache.kafka
kafka-clients
2.2.0
javax
javaee-api
8.0
org.springframework.boot
spring-boot-starter-websocket
kafka代码：
Producer
import org.apache.kafka.clients.producer.Callback;
import org.apache.kafka.clients.producer.KafkaProducer;
import org.apache.kafka.clients.producer.ProducerRecord;
import org.apache.kafka.clients.producer.RecordMetadata;
import org.apache.kafka.common.serialization.StringSerializer;
import org.apache.log4j.Logger;
import java.util.Properties;
public class Producer {
static Logger log = Logger.getLogger(Producer.class);
private static KafkaProducer producer = null;
/*
初始化生产者
*/
static {
Properties configs = initConfig();
producer = new KafkaProducer(configs);
}
/*
初始化配置
*/
private static Properties initConfig(){
Properties props = new Properties();
props.put("bootstrap.servers", MQDict.MQ_ADDRESS_COLLECTION);
props.put("acks", "all");
props.put("retries", 0);
props.put("batch.size", 16384);
props.put("key.serializer", StringSerializer.class.getName());
props.put("value.serializer", StringSerializer.class.getName());
return props;
}
}
SocketConsumer 和websocket结合 保持长监听
import org.apache.kafka.clients.consumer.Consumer;
import org.apache.kafka.clients.consumer.ConsumerRecord;
import org.apache.kafka.clients.consumer.ConsumerRecords;
import org.apache.kafka.clients.consumer.KafkaConsumer;
import org.apache.kafka.common.serialization.StringDeserializer;
import java.util.Arrays;
import java.util.Properties;
public class SocketConsumer extends Thread {
@Override
public void run(){
Properties props = new Properties();
props.put("bootstrap.servers", MQDict.MQ_ADDRESS_COLLECTION);
props.put("group.id", MQDict.CONSUMER_GROUP_ID);
props.put("enable.auto.commit", MQDict.CONSUMER_ENABLE_AUTO_COMMIT);
props.put("auto.commit.interval.ms", MQDict.CONSUMER_AUTO_COMMIT_INTERVAL_MS);
props.put("session.timeout.ms", MQDict.CONSUMER_SESSION_TIMEOUT_MS);
props.put("max.poll.records", MQDict.CONSUMER_MAX_POLL_RECORDS);
props.put("auto.offset.reset", "earliest");
props.put("key.deserializer", StringDeserializer.class.getName());
props.put("value.deserializer", StringDeserializer.class.getName());
Consumer consumer = new KafkaConsumer(props);
consumer.subscribe(Arrays.asList(MQDict.CONSUMER_TOPIC));
while (true) {
ConsumerRecords records = consumer.poll(MQDict.CONSUMER_POLL_TIME_OUT);
System.out.println("&&&&&&&&&&&&&&&&&&&&&&"+records.count()+"^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^");
for(ConsumerRecord c1: records) {
System.out.println(c1.value()+"%%%%%%"+"12345678");
WebSocketServer.sendMessage("utsDemo",c1.value());
}
}
}
}
ConsumerLinster 监听kafka消费者
import org.springframework.stereotype.Component;
@Component
public class ConsumerLinster {
public ConsumerLinster(){
SocketConsumer socketConsumer = new SocketConsumer();
socketConsumer.start();
}
}
websocket
WebSocketServer
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;
import javax.websocket.*;
import javax.websocket.server.PathParam;
import javax.websocket.server.ServerEndpoint;
import java.io.IOException;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.atomic.AtomicInteger;
@Component
@ServerEndpoint("/ws/{socketname}")
@Slf4j
public class WebSocketServer {
private Session session;
private static AtomicInteger onlineNum = new AtomicInteger();
private static Map map = new ConcurrentHashMap();
/**
-
建立连接
-
@param session session
-
@param socketname 用户ID
*/@OnOpen
public void onOpen(Session session, @PathParam(“socketname”) String socketname) {
int num = onlineNum.incrementAndGet();
this.session = session;
map.put(socketname, this.session);
log.info(“新建立客户端连接，sessionId为：{}，当前连接数为：{}”, session.getId(), num);
}
/**
-
关闭连接
-
@param session session
*/@OnClose
public void onClose(Session session) {
map.values().remove(session);
int num = onlineNum.decrementAndGet();
log.info(“sessionId为{}的客户端连接关闭，当前剩余连接数为：{}”, session.getId(), num);
}
/**
-
客户端发送消息
-
@param session session
-
@param message 消息
*/@OnMessage
public void onMessage(Session session, String message) {
log.info(“sessionId : {} , onMessage : {}”, session.getId(), message);
}
/**
-
发生错误
*/@OnError
public void onError(Session session, Throwable error) {
log.error(“WebSocket发生错误：{}，Session ID： {}”, error, session.getId());
}
/**
- 服务器端推送消息
*/
public static void sendMessage(String socketname,String jsonString){
Session nowsession = map.get(socketname);
if(nowsession!=null){
try {
nowsession.getBasicRemote().sendText(jsonString);
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
WebSocketConfig
@Configuration
public class WebSocketConfig extends ServerEndpointConfig.Configurator {
@Bean
public ServerEndpointExporter serverEndpointExporter() {
return new ServerEndpointExporter();
}
}
遇到session一直为null问题
RequestListener
@Component
@Slf4j
public class RequestListener implements ServletRequestListener {
@Override
public void requestInitialized(ServletRequestEvent sre) {
//将所有request请求都携带上httpSession
HttpSession session = ((HttpServletRequest) sre.getServletRequest()).getSession();
log.info(“将所有request请求都携带上httpSession {}”,session.getId());
}
public RequestListener() {}
@Override
public void requestDestroyed(ServletRequestEvent arg0) {}
}
kafka配置参数
public class MQDict {
public static final String MQ_ADDRESS_COLLECTION = "192.168.3.253:9092"; //kafka地址
public static final String CONSUMER_TOPIC = "utsDemo"; //消费者连接的topic
public static final String PRODUCER_TOPIC = "utsDemo"; //生产者连接的topic
public static final String CONSUMER_GROUP_ID = "1"; //groupId，可以分开配置
public static final String CONSUMER_ENABLE_AUTO_COMMIT = "true"; //是否自动提交（消费者）
public static final String CONSUMER_AUTO_COMMIT_INTERVAL_MS = "1000";
public static final String CONSUMER_SESSION_TIMEOUT_MS = "30000"; //连接超时时间
public static final int CONSUMER_MAX_POLL_RECORDS = 100; //每次拉取数
public static final Duration CONSUMER_POLL_TIME_OUT = Duration.ofMillis(3000); //拉去数据超时时间
}
参考文章：
https://www.cnblogs.com/coder163/p/8605645.html
有的文章是在忘记了 感谢分享相关内容的人