SpringCloud使用RabbitMQ 实现微服务之间的异步调用

　　最近公司内部员工为了完成小程序分裂考核任务，使用黑客软件发起大量请求刷任务，导致后台小程序模块A的微服务卡死，

微服务B调用了微服务A的微信消息推送功能，其他微服务又调用微服务B......

由于微服务A卡死，服务调用链产生阻塞，新的请求不断来到，阻塞的线程越来越多，最终因服务器资源耗尽而导致整个系统雪崩。

　　解决方法：使用RabbitMQ实现微服务之间的异步调用，从而实现解耦

       具体步骤：

       1、两个微服务工程 community 和 deliver  引入相同依赖（deliver异步调用community）

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<!-- RabbitMQ消息队列  -->         <dependency>             <groupId>org.springframework.cloud</groupId>             <artifactId>spring-cloud-starter-bus-amqp</artifactId>         </dependency>

　

　　配置文件bootstrap.yml，我司框架有公共的云端配置文件，配置如下：

 

 本地测试的配置如下：

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rabbitmq:     host: localhost     port: 5672     username: guest     password: guest

　　

　2、 发送方微服务deliver代码

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@Service("spTrDispatchDtlServiceImpl") import org.springframework.amqp.rabbit.core.RabbitTemplate; import org.springframework.amqp.core.Message; import org.springframework.amqp.core.MessageProperties; import org.springframework.amqp.rabbit.connection.CorrelationData;   @Autowired private RabbitTemplate rabbitTemplate; // 消息确认 final RabbitTemplate.ConfirmCallback confirmCallback = new RabbitTemplate.ConfirmCallback() {     @Override     public void confirm(CorrelationData correlationData, boolean ack, String cause) {         if (!ack) {             // 消息发送失败             System.err.println("调用community发送微信消息异常处理……");         }     } };   // 路由失败的监听 TODO rabbitmq接收信息失败后的处理 final RabbitTemplate.ReturnCallback returnCallback = new RabbitTemplate.ReturnCallback() {     @Override     public void returnedMessage(org.springframework.amqp.core.Message message, int replyCode, String replyText, String exchange, String routingKey) {         System.err.println("return exchange:" + exchange + ",routingKey:" + routingKey + ",replyText:" + replyText + ",replyCode:" + replyCode);     } };   public void pushDispatchMessage(List<SpTrDispatchDtl> dtlList) {                                    Map<String,Object> messStr = new HashMap<String, Object>();                         Map<String,Object> dataStr = new HashMap<String, Object> ();                         Map<String,Object> firstStr = new HashMap<String, Object> ();                         firstStr.put("value", "订单号");                           dataStr.put("first",firstStr);                         Map<String,Object> keyword1Str = new HashMap<String, Object> ();                         keyword1Str.put("value", "商品名称");                         dataStr.put("keyword1", keyword1Str);                         Map<String,Object> keyword2Str = new HashMap<String, Object> ();                         keyword2Str.put("value","用户名称");                         dataStr.put("keyword2", keyword2Str);                         Map<String,Object> keyword3Str = new HashMap<String, Object> ();                         keyword3Str.put("value","用户电话");                         keyword3Str.put("color", "#173177");                         dataStr.put("keyword3", keyword3Str);                                             Map<String,Object> keyword4Str = new HashMap<String, Object> ();                         keyword4Str.put("value", "配送地址");                         keyword4Str.put("color", "#173177");                         dataStr.put("keyword4", keyword4Str);                         Map<String,Object> keyword5Str = new HashMap<String, Object> ();                                                 keyword5Str.put("value", "配送时间");                         keyword5Str.put("color", "#173177");                         dataStr.put("keyword5", keyword5Str);                           Map<String,Object> remarkStr = new HashMap<String, Object> ();                         dataStr.put("remark", remarkStr);                         messStr.put("touser", wxuser.get("openid").toString());//接收者openid                         messStr.put("template_id", template_id);//微信模板ID                         messStr.put("data",dataStr);                         JSONObject jsonObj=new JSONObject(messStr);                           rabbitTemplate.setConfirmCallback(confirmCallback);                         rabbitTemplate.setReturnCallback(returnCallback);                         // 发送消息                         System.out.println("配送派工完成，向消息推送发送消息:"+jsonObj.toString());                           MessageProperties messageProperties = new MessageProperties();                         messageProperties.setContentType("application/json");                         Message message = new Message(jsonObj.toString().getBytes(),messageProperties);                         rabbitTemplate.convertAndSend("push_dispatch_**_exchange", "wxpush.msg.*", message); } } } }

　　

　　3、创建交换机和队列

       下载安装RabbitMQ参考：https://www.misboot.com/docs/bushuyunwei/RabbitMQ-anzhuang

        创建交换机：push_dispatch_**_exchange和队列 push_dispatch_**_queue

 　　关联交换机和队列 ，指定BindingKey ：wxpush.msg.*

 

 　　4、接收方community 代码

     启动类加注释 @EnableRabbit ，以及配置json转换器

 接受消息，创建监听者

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package cn.ewsd.community.utils;     import com.rabbitmq.client.Channel; import org.springframework.amqp.rabbit.annotation.*; import org.springframework.amqp.support.AmqpHeaders; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.messaging.handler.annotation.Headers; import org.springframework.messaging.handler.annotation.Payload; import org.springframework.stereotype.Component;   import java.io.IOException; import java.util.ArrayList; import java.util.Date; import java.util.List; import java.util.Map;   @Component public class wechaPushMsg {       @Autowired     private WeChatServiceImpl wechatServiceImpl;     @Autowired     private WxPustInfoMapper wxPustInfoMapper;       @RabbitListener(bindings = @QueueBinding(             value = @Queue(value = "push_dispatch_**_queue", durable = "true"),             exchange = @Exchange(                     value = "push_dispatch_**_exchange",                     durable = "true",                     type = "direct",                     ignoreDeclarationExceptions = "true"),             key = "wxpush.msg.*"     ))     @RabbitHandler     public void processMessage(@Payload Map<String,Object> pushMsg, Channel channel, @Headers Map<String, Object> headers) throws IOException {         Long deliveryTag = (Long) headers.get(AmqpHeaders.DELIVERY_TAG);         System.out.println("接受到了push_dispatch_**_queue信息");         // 获取信息         try {             //调用消息推送方法             Map<String,Object> resultMap = wechatServiceImpl.pushOneUser(pushMsg);             if(resultMap.get("returncode").toString().equals("1")){                   //2 记录已推送表                 WxPustInfo wxPustInfo = new WxPustInfo();                 String memo = "推送内容：" + data.toString();<br>                //详细数据略过                 wxPustInfo.setMemo(memo);                 wxPustInfoMapper.insertSelective(wxPustInfo);             }         }catch (Exception e){             System.out.println("【信息存储失败】"+e.getMessage());             e.printStackTrace();         }         // 手工ack         channel.basicAck(deliveryTag,false);     } }

　

    5、遇到的问题

    前期直接发送json字符串，一直报错：

Could not convert incoming message with content-type [text/plain], 'json' keyword missing

后在发送时指定格式后解决问题，代码如下：

参考文章：
https://www.cnblogs.com/sss4/p/16423718.html
https://www.bilibili.com/read/cv4081623