一、訊息佇列的作用

1、非同步處理

2、流量削峰

3、應用解耦

4、日誌處理

二、此處展示的是非同步處理場景

1、構建maven專案，此處不做多餘的說明了，匯入MQ相關的jar包,注意版本的問題，這裡費了好多時間解決衝突

<!-- MQ  start-->
//我的spring版本為 4.2.3.RELEASE

// 這裡用了mq為 5.11.1的版本，因為5.15以上的版本，
會包含spring的包，導致與spring的包衝突，各種報錯，
浪費了好多時間去查詢整理

<dependency>
  <groupId>org.apache.activemq</groupId>
  <artifactId>activemq-all</artifactId>
  <version>5.11.1</version>
</dependency>
<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-jms</artifactId>
  <version>${spring.version}</version>
</dependency>
<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-messaging</artifactId>
  <version>${spring.version}</version>
</dependency>
<dependency>
  <groupId>org.apache.activemq</groupId>
  <artifactId>activemq-pool</artifactId>
  <version>5.11.1</version>
</dependency>
	<dependency>
	<groupId>org.apache.xbean</groupId>
	<artifactId>xbean-spring</artifactId>
	<version>4.6</version>
</dependency>
<!-- MQ  end-->
 

2、寫一個處理郵件訊息佇列的處理類

import javax.jms.Destination;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jms.core.JmsTemplate;
import org.springframework.stereotype.Component;

@Component
public class EmailProcessor {
	
	@Autowired
	private JmsTemplate jmsTplate;
	
	public void sendEmailInfo2Queue(Destination destination, String message){
		System.out.println("======= 傳送郵件的請求訊息到訊息佇列=======");
		jmsTplate.convertAndSend(destination, message);
	}
}
 

3、實現訊息監聽器

import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.MessageListener;
import javax.jms.TextMessage;

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

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;

/**
 * 實現 訊息佇列監聽器，監聽訊息佇列
 * 當監聽到佇列中有訊息時，進行訊息消費
 * @author Administrator
 *
 */
@Component
public class DoSendEmail implements MessageListener{
	
	@Autowired
	private EmailSender emailSender;
	
	/**
	 * 監聽的方法實現
	 */
	public void onMessage(Message message) {
		TextMessage textMsg = (TextMessage)message;
		try {
			JSONObject jsonObject = JSON.parseObject(textMsg.getText());
			 emailSender.sendEmail(jsonObject.getString("email"),jsonObject.getString("code"),jsonObject.getString("username"));
		} catch (JMSException e) {
			e.printStackTrace();
		}
	}
	
}
 

4、實現上面使用到的郵件傳送類,使用javax.mail類

import java.util.Properties;

import javax.mail.Authenticator;
import javax.mail.Message;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;

import org.springframework.stereotype.Component;

@Component
public class EmailSender {
	// 傳送者的郵箱
	private static final String FROM_EMAIL_ADDR = "xxx";
	// 授權碼，即密碼
	public static final String FROM_MAIL_PWD = "xxx";
	
	public void sendEmail(String to, String code, String username) {
		
		//1、建立一個程式與郵件伺服器會話物件 Session
		Properties prop = new Properties();
		prop.setProperty("mail.transport.protocol", "SMTP");
        prop.setProperty("mail.smtp.host","smtp.163.com");
        prop.setProperty("mail.smtp.port", "25");
        // 指定驗證為true
        prop.setProperty("mail.smtp.auth", "true");
        prop.setProperty("mail.smtp.timeout","1000");
        // 驗證賬號及密碼，密碼需要是第三方授權碼
        Authenticator authc = new Authenticator() {
        	@Override
            protected PasswordAuthentication getPasswordAuthentication() {
                return new PasswordAuthentication(FROM_EMAIL_ADDR, FROM_MAIL_PWD);
            }
		};
		
		Session session = Session.getInstance(prop, authc);
		// 2、建立messege
        Message msg = new MimeMessage(session);
        try {
        	 // 設定傳送者郵箱
			msg.setFrom(new InternetAddress(FROM_EMAIL_ADDR));
			 // 設定傳送方式與接收者
	        msg.setRecipient(Message.RecipientType.TO, new InternetAddress(to));
	        // 設定主題
	        msg.setSubject("郵件傳送測試");
	        // 設定內容
	        msg.setContent(code, "text/html;charset=utf-8");
	        Transport.send(msg);
		} catch (Exception e) {
			e.printStackTrace();
		} 
        
	}
	
}

5、在使用者登入驗證成功後，加入傳送訊息佇列的程式碼

// 使用者登入後，給使用者傳送郵件，提示使用者登入資訊
//此處程式碼加在驗證使用者成功，返回頁面之前
Destination destination = new ActiveMQQueue("email.queue");
Map<String,String> emailParam = new HashMap<String,String>();
emailParam.put("email","[email protected]");
emailParam.put("code", "ABCDEFG");
emailParam.put("username","FX");
String message = JSON.toJSONString(emailParam);
emailProcessor.sendEmailInfo2Queue(destination,message);

6、配置jms, 本次單獨使用一個spring-jms.xml

<?xml version="1.0" encoding="UTF-8"?>
<!--suppress SpringFacetInspection -->
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xmlns:amq="http://activemq.apache.org/schema/core"
       xmlns:jms="http://www.springframework.org/schema/jms"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
    http://www.springframework.org/schema/jms
    http://www.springframework.org/schema/jms/spring-jms-4.0.xsd
    http://activemq.apache.org/schema/core
    http://activemq.apache.org/schema/core/activemq-core-5.8.0.xsd"
>

	<!-- 連線MQ -->
	<amq:connectionFactory id="amqConnectionFactory" brokerURL="tcp://localhost:61616" userName="admin" password="admin"/>
	
	<!-- 交給spring管理 -->
	<bean id="connectionFactory" class="org.springframework.jms.connection.CachingConnectionFactory">
		<property name="targetConnectionFactory" ref="amqConnectionFactory"/>
		<property name="sessionCacheSize" value="10"/>
	</bean>
	
	<!-- JMS模板 -->
	<bean id="jmsTemplate" class="org.springframework.jms.core.JmsTemplate">
		<property name="connectionFactory" ref="connectionFactory"/>
		<!-- 如果為True，則是Topic；如果是false或者預設，則是queue -->
		<property name="pubSubDomain" value="false"/>
	</bean>
	
	<!-- JMS監聽器 -->
	<jms:listener-container destination-type="queue" connection-factory="connectionFactory">
		<!-- 使用doSendEmail物件  監聽 email.queue 的訊息佇列，當有訊息時，進行消費 -->
		<jms:listener destination="email.queue" ref="doSendEmail"/>
	</jms:listener-container>
	
</beans>

7、當然要在spring的配置檔案中加入

<import resource="spring-jms.xml"/>

8、啟動專案，登入，可以發現郵箱中已經收到郵件了。