Topic模式
2021.07

Topic模式(话题模式,一个消息被多个消费者获取,消息的目标queue可用BindingKey以通配符,(#:一个或多个词,*:一个词)的方式指定

Topic模式

星号井号代表通配符星号代表多个单词,井号代表一个单词路由功能添加模糊匹配消息产生者产生消息,把消息交给交换机交换机根据key的规则模糊匹配到对应的队列,由队列的监听消费者接收消息消费 目录结构 Topic模式 kuteng-RabbitMQ -RabbitMQ –rabitmq.go //这个是RabbitMQ的封装 -publish –mainpublish.go //Publish 先启动 -recieve1 –mainrecieve.go -recieve2 –mainrecieve.go rabitmq.go代码

package RabbitMQ

import (
    "fmt"
    "log"

    "github.com/streadway/amqp"
)

//连接信息
const MQURL = "amqp://kuteng:kuteng@127.0.0.1:5672/kuteng"

//rabbitMQ结构体
type RabbitMQ struct {
    conn    *amqp.Connection
    channel *amqp.Channel
    //队列名称
    QueueName string
    //交换机名称
    Exchange string
    //bind Key 名称
    Key string
    //连接信息
    Mqurl string
}

//创建结构体实例
func NewRabbitMQ(queueName string, exchange string, key string) *RabbitMQ {
    return &RabbitMQ{QueueName: queueName, Exchange: exchange, Key: key, Mqurl: MQURL}
}

//断开channel 和 connection
func (r *RabbitMQ) Destory() {
    r.channel.Close()
    r.conn.Close()
}

//错误处理函数
func (r *RabbitMQ) failOnErr(err error, message string) {
    if err != nil {
        log.Fatalf("%s:%s", message, err)
        panic(fmt.Sprintf("%s:%s", message, err))
    }
}

//话题模式
//创建RabbitMQ实例
func NewRabbitMQTopic(exchangeName string, routingKey string) *RabbitMQ {
    //创建RabbitMQ实例
    rabbitmq := NewRabbitMQ("", exchangeName, routingKey)
    var err error
    //获取connection
    rabbitmq.conn, err = amqp.Dial(rabbitmq.Mqurl)
    rabbitmq.failOnErr(err, "failed to connect rabbitmq!")
    //获取channel
    rabbitmq.channel, err = rabbitmq.conn.Channel()
    rabbitmq.failOnErr(err, "failed to open a channel")
    return rabbitmq
}

//话题模式发送消息
func (r *RabbitMQ) PublishTopic(message string) {
    //1.尝试创建交换机
    err := r.channel.ExchangeDeclare(
        r.Exchange,
        //要改成topic
        "topic",
        true,
        false,
        false,
        false,
        nil,
    )

    r.failOnErr(err, "Failed to declare an excha"+
        "nge")

    //2.发送消息
    err = r.channel.Publish(
        r.Exchange,
        //要设置
        r.Key,
        false,
        false,
        amqp.Publishing{
            ContentType: "text/plain",
            Body:        []byte(message),
        })
}

//话题模式接受消息
//要注意key,规则
//其中“*”用于匹配一个单词,“#”用于匹配多个单词(可以是零个)
//匹配 kuteng.* 表示匹配 kuteng.hello, kuteng.hello.one需要用kuteng.#才能匹配到
func (r *RabbitMQ) RecieveTopic() {
    //1.试探性创建交换机
    err := r.channel.ExchangeDeclare(
        r.Exchange,
        //交换机类型
        "topic",
        true,
        false,
        false,
        false,
        nil,
    )
    r.failOnErr(err, "Failed to declare an exch"+
        "ange")
    //2.试探性创建队列,这里注意队列名称不要写
    q, err := r.channel.QueueDeclare(
        "", //随机生产队列名称
        false,
        false,
        true,
        false,
        nil,
    )
    r.failOnErr(err, "Failed to declare a queue")

    //绑定队列到 exchange 中
    err = r.channel.QueueBind(
        q.Name,
        //在pub/sub模式下,这里的key要为空
        r.Key,
        r.Exchange,
        false,
        nil)

    //消费消息
    messges, err := r.channel.Consume(
        q.Name,
        "",
        true,
        false,
        false,
        false,
        nil,
    )

    forever := make(chan bool)

    go func() {
        for d := range messges {
            log.Printf("Received a message: %s", d.Body)
        }
    }()

    fmt.Println("退出请按 CTRL+C\n")
    <-forever
}

mainpublish.go代码

package main

import (
    "fmt"
    "strconv"
    "time"

    "github.com/student/kuteng-RabbitMQ/RabbitMQ"
)

func main() {
    kutengOne := RabbitMQ.NewRabbitMQTopic("exKutengTopic", "kuteng.topic.one")
    kutengTwo := RabbitMQ.NewRabbitMQTopic("exKutengTopic", "kuteng.topic.two")
    for i := 0; i <= 100; i++ {
        kutengOne.PublishTopic("Hello kuteng topic one!" + strconv.Itoa(i))
        kutengTwo.PublishTopic("Hello kuteng topic Two!" + strconv.Itoa(i))
        time.Sleep(1 * time.Second)
        fmt.Println(i)
    }

}

recieve1/mainrecieve.go代码

package main

import "github.com/student/kuteng-RabbitMQ/RabbitMQ"

func main() {
    kutengOne := RabbitMQ.NewRabbitMQTopic("exKutengTopic", "#")
    kutengOne.RecieveTopic()
}

recieve2/mainrecieve.go代码

package main

import "github.com/student/kuteng-RabbitMQ/RabbitMQ"

func main() {
    kutengOne := RabbitMQ.NewRabbitMQTopic("exKutengTopic", "kuteng.*.two")
    kutengOne.RecieveTopic()
}
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