牛客项目（五）-使用kafka实现发送系统通知

kafka入门以及与spring整合

Message.java

import java.util.Date;

public class Message {
    private int id;
    private int fromId;
    private int toId;
    private String conversationId;
    private String content;
    private int status;
    private Date createTime;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public int getFromId() {
        return fromId;
    }

    public void setFromId(int fromId) {
        this.fromId = fromId;
    }

    public int getToId() {
        return toId;
    }

    public void setToId(int toId) {
        this.toId = toId;
    }

    public String getConversationId() {
        return conversationId;
    }

    public void setConversationId(String conversationId) {
        this.conversationId = conversationId;
    }

    public String getContent() {
        return content;
    }

    public void setContent(String content) {
        this.content = content;
    }

    public int getStatus() {
        return status;
    }

    public void setStatus(int status) {
        this.status = status;
    }

    public Date getCreateTime() {
        return createTime;
    }

    public void setCreateTime(Date createTime) {
        this.createTime = createTime;
    }

    @Override
    public String toString() {
        return "Message{" +
                "id=" + id +
                ", fromId=" + fromId +
                ", toId=" + toId +
                ", conversationId='" + conversationId + '\'' +
                ", content='" + content + '\'' +
                ", status=" + status +
                ", createTime=" + createTime +
                '}';
    }
}

EventConsumer.java

定义事件消费者

import com.alibaba.fastjson.JSONObject;
import edu.npu.newcoder.community.community.entity.DiscussPost;
import edu.npu.newcoder.community.community.entity.Event;
import edu.npu.newcoder.community.community.entity.Message;
import edu.npu.newcoder.community.community.service.DiscussPostService;
import edu.npu.newcoder.community.community.service.ElasticsearchService;
import edu.npu.newcoder.community.community.service.MessageService;
import edu.npu.newcoder.community.community.util.CommunityConstant;
import org.apache.kafka.clients.consumer.ConsumerRecord;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.kafka.annotation.KafkaListener;
import org.springframework.stereotype.Component;

import java.util.Date;
import java.util.HashMap;
import java.util.Map;

@Component
public class EventConsumer implements CommunityConstant {
//    private static final Logger logger= LoggerFactory.getLogger(EventConsumer.class);
    @Autowired
    private MessageService messageService;
    @Autowired
    private DiscussPostService discussPostService;
    @Autowired
    private ElasticsearchService elasticsearchService;
    //加一个监听相关主题的listener
    @KafkaListener(topics = {TOPIC_COMMENT,TOPIC_LIKE,TOPIC_FOLLOW})
    public void handleCommentMessage(ConsumerRecord record){
        if(record == null || record.value()==null){
            System.out.println("错误发帖");
            return;
        }
        Event event= JSONObject.parseObject(record.value().toString(),Event.class);
        if(event == null){
            System.out.println("错误发帖");
            return;
        }
        //发送站内通知
        Message message = new Message();
        message.setFromId(SYSTEM_USERID);
        message.setToId(event.getEntityUserId());
        message.setConversationId(event.getTopic());
        message.setCreateTime(new Date());
        //message的内容
        Map<String,Object> content=new HashMap<>();
        content.put("userId",event.getUserId());
        content.put("entityType",event.getEntityType());
        content.put("entityId",event.getEntityId());
        if(!event.getData().isEmpty()){
            for(Map.Entry<String,Object> entry:event.getData().entrySet()){
                content.put(entry.getKey(),entry.getValue());
            }
        }
        message.setContent(JSONObject.toJSONString(content));
        System.out.println(message);
        messageService.addMessage(message);
        System.out.println("成功处理事件");
    }
    }

Event.java

定义一个事件实体 以方便在消息的发送与处理

import java.util.HashMap;
import java.util.Map;

//用于事件驱动的kafka消息队列开发
public class Event {
    private String topic;
    //事件触发的人
    private int userId;
    //事件发生在哪个实体
    private int entityType;
    private int entityId;
    //实体作者
    private int entityUserId;
    //存储额外数据
    private Map<String,Object> data = new HashMap<>();

    public String getTopic() {
        return topic;
    }

    public Event setTopic(String topic) {
        this.topic = topic;
        return this;
    }

    public int getUserId() {
        return userId;
    }

    public Event setUserId(int userId) {
        this.userId = userId;
        return this;
    }

    public int getEntityType() {
        return entityType;
    }

    public Event setEntityType(int entityType) {
        this.entityType = entityType;
        return this;
    }

    public int getEntityId() {
        return entityId;
    }

    public Event setEntityId(int entityId) {
        this.entityId = entityId;
        return this;
    }

    public int getEntityUserId() {
        return entityUserId;
    }

    public Event setEntityUserId(int entityUserId) {
        this.entityUserId = entityUserId;
        return this;
    }

    public Map<String, Object> getData() {
        return data;
    }

    public Event setData(String key,Object value) {
        this.data.put(key,value);
        return this;
    }

}

EventProducer.java

定义事件的生产者

import com.alibaba.fastjson.JSONObject;
import edu.npu.newcoder.community.community.entity.Event;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.kafka.core.KafkaTemplate;
import org.springframework.stereotype.Component;

@Component
public class EventProducer {
//生产者使用kafkaTemplate发送消息
    @Autowired
    KafkaTemplate kafkaTemplate;
    //处理事件
    public void fireEvent(Event event){
        //将事件发布到指定的主题
        //将event转换为json数据进行消息发送
        kafkaTemplate.send(event.getTopic(), JSONObject.toJSONString(event));
        System.out.println("成功发送"+event.getTopic());

    }
}

EventConsumer.java

定义事件消费者

import com.alibaba.fastjson.JSONObject;
import edu.npu.newcoder.community.community.entity.DiscussPost;
import edu.npu.newcoder.community.community.entity.Event;
import edu.npu.newcoder.community.community.entity.Message;
import edu.npu.newcoder.community.community.service.DiscussPostService;
import edu.npu.newcoder.community.community.service.ElasticsearchService;
import edu.npu.newcoder.community.community.service.MessageService;
import edu.npu.newcoder.community.community.util.CommunityConstant;
import org.apache.kafka.clients.consumer.ConsumerRecord;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.kafka.annotation.KafkaListener;
import org.springframework.stereotype.Component;

import java.util.Date;
import java.util.HashMap;
import java.util.Map;

@Component
public class EventConsumer implements CommunityConstant {
//    private static final Logger logger= LoggerFactory.getLogger(EventConsumer.class);
    @Autowired
    private MessageService messageService;
    @Autowired
    private DiscussPostService discussPostService;
    @Autowired
    private ElasticsearchService elasticsearchService;
    //加一个监听相关主题的listener
    @KafkaListener(topics = {TOPIC_COMMENT,TOPIC_LIKE,TOPIC_FOLLOW})
    public void handleCommentMessage(ConsumerRecord record){
        if(record == null || record.value()==null){
            System.out.println("错误发帖");
            return;
        }
        Event event= JSONObject.parseObject(record.value().toString(),Event.class);
        if(event == null){
            System.out.println("错误发帖");
            return;
        }
        //发送站内通知
        Message message = new Message();
        message.setFromId(SYSTEM_USERID);
        message.setToId(event.getEntityUserId());
        message.setConversationId(event.getTopic());
        message.setCreateTime(new Date());
        //message的内容
        Map<String,Object> content=new HashMap<>();
        content.put("userId",event.getUserId());
        content.put("entityType",event.getEntityType());
        content.put("entityId",event.getEntityId());
        if(!event.getData().isEmpty()){
            for(Map.Entry<String,Object> entry:event.getData().entrySet()){
                content.put(entry.getKey(),entry.getValue());
            }
        }
        message.setContent(JSONObject.toJSONString(content));
        System.out.println(message);
        messageService.addMessage(message);
        System.out.println("成功处理事件");
    }
    }

在特定的地方触发消息产生

CommentController

 //触发评论事件
        Event event=new Event().setTopic(TOPIC_COMMENT)
                .setUserId(hostHolder.getUser().getId())
                .setEntityType(comment.getEntityType())
                .setEntityId(comment.getEntityId())
                .setData("postId",discussPostId);
        if(comment.getEntityType() == ENTITY_TYPE_POST){
            DiscussPost target=discussPostService.findDiscussPostById(comment.getEntityId());
            event.setEntityUserId(target.getUserId());
        }else if(comment.getEntityType()==ENTITY_TYPE_COMMENT){
            //根据评论的id查询评论
            Comment target =commentService.findCommentById(comment.getEntityId());
            event.setEntityUserId(target.getUserId());
        }
         eventProducer.fireEvent(event);

LikeController

 //触发点赞事件
 if(likeStatus ==1){
            Event event =new Event()
                    .setTopic(TOPIC_LIKE)
                    .setUserId(hostHolder.getUser().getId())
                    .setEntityType(entityType)
                    .setEntityId(entityId)
                    .setEntityUserId(entityUserId)
                    .setData("postId",postId);
            eventProducer.fireEvent(event);
        }

FollowController

 //触发关注事件
 Event event = new Event()
                .setTopic(TOPIC_FOLLOW)
                .setUserId(hostHolder.getUser().getId())
                .setEntityType(entityType)
                .setEntityId(entityId)
                .setEntityUserId(entityId);
        eventProducer.fireEvent(event);