RabbitMQ（7）-发后即忘模型
发后即忘模型：简单说就是创建了任务，放置到交换器上，让应用程序继续返回工作
如：
通知---对发生事件的描述，内容可以是日志，可以报告给管理员或者程序
批处理---针对大数据集合的工作或者转换
一.告警系统
会自动将告警信息路由到critical队列或者rate_limit队列上
1.告警系统生产者：
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
public class AlertWarningProducer {
private static final String EXCHANGE_NAME = "alerts";
private static final String ROUTING_KEY = "critical.alert";
//private static final String ROUTING_KEY = "alert.rate_limt";
public static void main(String[] argv) {
Connection connection = null;
Channel channel = null;
try {
ConnectionFactory factory = new ConnectionFactory();
factory.setHost("liuzhaoqiang128");
factory.setUsername("admin");
factory.setPassword("admin");
factory.setPort(5672);
connection = factory.newConnection();
channel = connection.createChannel();
channel.exchangeDeclare(EXCHANGE_NAME, "topic",true);
String message = "critical content！！！";
//String message = "rate_limt content！！！";
//消息发布
channel.basicPublish(EXCHANGE_NAME, ROUTING_KEY, null, message.getBytes());
System.out.println(" [x] Sent '" + ROUTING_KEY + "':'" + message + "'");
}
catch (Exception e) {
e.printStackTrace();
}
finally {
if (connection != null) {
try {
connection.close();
}
catch (Exception ignore) {}
}
}
}
}
2.告警系统消费者
import com.rabbitmq.client.*;
import javax.mail.*;
import javax.mail.Message.RecipientType;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;
import java.io.IOException;
import java.util.Properties;
import java.util.concurrent.TimeoutException;
public class AlertWarningConsumer {
private final static String EMAIL_RECIPIENTS="*******@163.com";//接收者
private final static String EMAIL_SENDER="*******@163.com";//发送者
private final static String EXCHANGE="alerts";
private final static String TYPE="topic";
private final static String QUEUE1="critical";
private final static String QUEUE2="rate_limt";
private final static String ROUTING_KEY1="critical.*";
private final static String ROUTING_KEY2="*.rate_limt";
/**
*
* @param recipients 接收人
* @param subject 发送主题
* @param msg 发送消息内容
* @throws IOException
* @throws MessagingException
*/
public static void sendEmail(String recipients, String subject, Object msg) throws IOException, MessagingException {
final Properties props = new Properties();
/*
* 可用的属性： mail.store.protocol / mail.transport.protocol / mail.host /
* mail.user / mail.from
*/
// 表示SMTP发送邮件，需要进行身份验证
props.put("mail.smtp.auth", "true");
props.put("mail.smtp.host", "smtp.163.com");
// 发件人的账号
props.put("mail.user", EMAIL_SENDER);
// 访问SMTP服务时需要提供的密码
props.put("mail.password", "qiangzai123");
// 构建授权信息，用于进行SMTP进行身份验证
Authenticator authenticator = new Authenticator() {
@Override
protected PasswordAuthentication getPasswordAuthentication() {
// 用户名、密码
String userName = props.getProperty("mail.user");
String password = props.getProperty("mail.password");
return new PasswordAuthentication(userName, password);
}
};
// 使用环境属性和授权信息，创建邮件会话
Session mailSession = Session.getInstance(props, authenticator);
// 创建邮件消息
MimeMessage message = new MimeMessage(mailSession);
// 设置发件人
InternetAddress form = new InternetAddress(
props.getProperty("mail.user"));
message.setFrom(form);
// 设置收件人
InternetAddress to = new InternetAddress(recipients);
message.setRecipient(RecipientType.TO, to);
// 设置邮件标题
message.setSubject(subject);
// 设置邮件的内容体{"message":"告警消息邮件发送"}
message.setContent(msg, "application/json;charset=UTF-8");
// 发送邮件
Transport.send(message);
}
public static void main(String[] args) {
ConnectionFactory factory = new ConnectionFactory();
Connection connection = null;
try {
factory.setPort(5672);
factory.setHost("liuzhaoqiang128");
factory.setUsername("admin");
factory.setPassword("admin");
connection = factory.newConnection();
//创建连接
final Channel channel = connection.createChannel();
//声明交换器队列绑定等信息
channel.exchangeDeclare(EXCHANGE, TYPE, true);
channel.queueDeclare(QUEUE1, false, false, false, null);
channel.queueBind(QUEUE1,EXCHANGE,ROUTING_KEY1);
channel.queueDeclare(QUEUE2, false, false, false, null);
channel.queueBind(QUEUE2,EXCHANGE,ROUTING_KEY2);
Consumer rate_limit_notify = new DefaultConsumer(channel){
@Override
public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
String subject = "rate_limit Alert";
String msg = new String(body,"UTF-8");
try {
sendEmail(EMAIL_RECIPIENTS, subject, msg);
} catch (MessagingException e) {
e.printStackTrace();
}
System.out.println("send alert E-mail!Alert text:Recipients: " + EMAIL_RECIPIENTS+" subject: "+subject);
channel.basicAck(envelope.getDeliveryTag(),false);
}
};
Consumer critical_notify = new DefaultConsumer(channel){
@Override
public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
String subject = "Critical Alert";
String msg = new String(body,"UTF-8");
try {
sendEmail(EMAIL_RECIPIENTS, subject, msg);
} catch (MessagingException e) {
e.printStackTrace();
}
System.out.println("send alert E-mail!Alert text:Recipients: " + EMAIL_RECIPIENTS+" subject: "+subject);
channel.basicAck(envelope.getDeliveryTag(),false);
}
};
//消息消费
channel.basicConsume(QUEUE1,false,"critical",critical_notify);
channel.basicConsume(QUEUE2,false,"rate_limit",rate_limit_notify);
} catch (IOException e) {
e.printStackTrace();
} catch (TimeoutException e) {
e.printStackTrace();
}
}
}
二.并行处理
如上图所示，可以看到一个名为"upload-pictures"的交换器，下方绑定了几个queue
其中一个使用场景，有三个任务，图片尺寸调整、奖励用户积分以及通知所有用户，这几个任务需要并行处理，因为这几个任务毫不相干，不需要等待上一个任务完成，现在想增加一个新类型的任务，譬如日志记录，只需定义新的队列绑定到upload-pictures交换器上即可
例如图片上传通过RbbitMQ发布一条元数据信息，然后让他真正执行任务的异步工作者去处理即可
部分代码实现如下：
1.信息发布者
import com.rabbitmq.client.*;
public class UploadPicturePublish {
private static final String EXCHANGE_NAME = "upload_pictures";
public static void main(String[] argv) {
ConnectionFactory factory = new ConnectionFactory();
Connection connection = null;
Channel channel = null;
try {
factory.setHost("liuzhaoqiang129");
factory.setUsername("admin");
factory.setPassword("admin");
factory.setPort(5672);
connection = factory.newConnection();
channel = connection.createChannel();
channel.exchangeDeclare(EXCHANGE_NAME,"fanout",true,false,false,null);
String jsonMessage = "{\"image_id\":123456,\"user_id\":123456,\"image_path\":\"pic_jpg\"}";
channel.basicPublish(EXCHANGE_NAME,"", MessageProperties.PERSISTENT_TEXT_PLAIN,jsonMessage.getBytes("UTF-8"));
System.out.println("Send message:" + jsonMessage);
Thread.sleep(10000);
}
catch (Exception e) {
e.printStackTrace();
}
finally {
if (connection != null) {
try {
connection.close();
}
catch (Exception ignore) {}
}
}
}
}
2.消费者
import com.alibaba.fastjson.JSON;
import com.rabbitmq.client.*;
import java.io.IOException;
public class UploadPictureConsumer {
private static final String EXCHANGE_NAME = "upload_pictures";
private static final String QUEUE="add_points";
private static final String QUEUE1="resize_pictures";
private static final String QUEUE2="notify-friends";
private static final String QUEUE3="logs";
public static void main(String[] argv) {
ConnectionFactory factory = new ConnectionFactory();
Connection connection = null;
Channel channel = null;
try {
factory.setHost("liuzhaoqiang129");
factory.setUsername("admin");
factory.setPassword("admin");
factory.setPort(5672);
connection = factory.newConnection();
channel = connection.createChannel();
channel.exchangeDeclare(EXCHANGE_NAME, "fanout", true, false, false, null);
//积分消费
Consumer add_point = integrationConsumer(channel);
channel.basicConsume(QUEUE,false,add_point);
Thread.sleep(10000);
}
catch (Exception e) {
e.printStackTrace();
}
finally {
if (connection != null) {
try {
connection.close();
}
catch (Exception ignore) {}
}
}
}
public static Consumer integrationConsumer(final Channel channel){
channel.queueDeclare(QUEUE,false,false,false,null);
channel.queueBind(QUEUE,EXCHANGE_NAME,"");
//这里有一个应用场景就是可以获取元数据中的用户ID，这样可以从数据库中获取所有联系人，去通知联系人
//这里的回调函数可以动态注册
Consumer add_point = new DefaultConsumer(channel) {
@Override
public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
String jsonString = new String(body,"UTF-8");
String message = JSON.parseObject(jsonString).getString("user_id");
if(message.equals("quit")){
channel.basicCancel(consumerTag);
}
System.out.println("Adding to points to user: " + message);
channel.basicAck(envelope.getDeliveryTag(),false);
}
};
return add_point;
}
public static Consumer resizePictures(final Channel channel){
channel.queueDeclare(QUEUE1,false,false,false,null);
channel.queueBind(QUEUE1,EXCHANGE_NAME,"");
Consumer resize_pictures = new DefaultConsumer(channel) {
@Override
public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
String jsonString = new String(body,"UTF-8");
String image_id = JSON.parseObject(jsonString).getString("image_id");
String image_path = JSON.parseObject(jsonString).getString("image_path");
System.out.println("Adding to points to user: " + image_id+"---"+image_path);
channel.basicAck(envelope.getDeliveryTag(),false);
}
};
return resize_pictures;
}
}