一、rabbitMq应用场景
1、异步处理：传统的注册成功，注册写入数据库，在发送邮箱，在发送短信，则返回注册成功，利用rabbitmq异步处理，直接写入数据库后返回注册成功，之后再去rabbitmq消费发送邮箱和短信。
2、双11狂欢节，传统做法应用解耦：订单系统访问库存系统，这种做法有缺点，库存系统出现故障，订单会丢失，可以采用rabbitmq，订单系统下单成功，写入rabbitmq返回下单成功，订阅模式，库存系统去rabbitmq消费。
3、流量削峰，秒杀活动中，人流量太大，存入rabbitmq：可以控制人数，订单超过值，直接丢弃,秒杀失败，缓解短时间流量太大压垮应用。
二、rabbitMq代码实例
首先引入maven包，集成springboot在代码配置文件加上：
代码语言：javascript复制 <dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-amqp</artifactId>
</dependency>
# ----- RabbitMq -------- #
spring.rabbitmq.virtual-host=/
spring.rabbitmq.host=localhost
spring.rabbitmq.port=5672
spring.rabbitmq.username=admin
spring.rabbitmq.password=adminwork模式（多对多使用）：
代码语言：javascript复制@Component
public class RabbitQuestConfig {
@Bean
public Queue create(){
return new Queue("work");
}
}接口里写上：
代码语言：javascript复制 @RequestMapping("/work")
public void work() {
String str = "work";
for (int i = 0; i < 100; i ) {
rabbitTemplate.convertAndSend("work", str);
}
}代码语言：javascript复制
@Component
@Slf4j
public class ConsumerRabbitMq {
@Resource
private RabbitMqMapper rabbitMqMapper;
@RabbitListener(queues = "work")
public void test(String message) {
System.out.println("work消费成功1:" message);
}
@RabbitListener(queues = "work")
public void test2(String message) {
System.out.println("work消费成功2:" message);
}
}Topic Exchage(主题订阅)
topic 是RabbitMQ中最灵活的一种方式，可以根据routing_key自由的绑定不同的队列
代码语言：javascript复制@Configuration
public class TopicRabbitConfig {
final static String message = "topic_message";
final static String messages = "topic_messages";
@Bean
public Queue topicMessage() {
return new Queue(TopicRabbitConfig.message);
}
@Bean
public Queue topicMessages() {
return new Queue(TopicRabbitConfig.messages);
}
/**
* 声明topic交换机
*
* @return
*/
@Bean
TopicExchange topicExchange() {
return new TopicExchange("topicExchange");
}
/**
* 绑定queue交换机
* 只能消费message
*/
@Bean
Binding bindExchangeMessage(Queue topicMessage, TopicExchange topicExchange) {
return BindingBuilder.bind(topicMessage).to(topicExchange).with("topic.message");
}
/**
* 绑定queue交换机
* 全部都可以消费，包含message，messages
*/
@Bean
Binding bindExchangeMessages(Queue topicMessages, TopicExchange topicExchange) {
return BindingBuilder.bind(topicMessages).to(topicExchange).with("topic.#");
}
}代码语言：javascript复制
/**
* topic
*/
@RequestMapping("/topic")
public void topic() {
for (int i = 0; i < 50; i ) {
String topicMessage1 = "topicMessage1";
rabbitTemplate.convertAndSend("topicExchange", "topic.message", topicMessage1);
String topicMessage2 = "2topicMessage2";
rabbitTemplate.convertAndSend("topicExchange", "topic.messages", topicMessage2);
}
}
//消费者：
@RabbitListener(queues = "topic_message")
public void topicMessage1(String message) {
System.out.println("topicMessage 消费成功只能消费 topicMessage1:" message);
}
/**
* topic
*/
@RabbitListener(queues = "topic_messages")
public void topicMessage2(String message) {
System.out.println("topicMessages 消费 topicMessage1 & topicMessage2:" message);
}Fanout Exchange(广播模式)：
代码语言：javascript复制@Configuration
public class FanoutRabbitConfig {
@Bean
public Queue aMessage(){
return new Queue("a_message");
}
@Bean
public Queue bMessage(){
return new Queue("b_message");
}
@Bean
FanoutExchange fanoutExchange(){
return new FanoutExchange("fanoutExchange");
}
@Bean
Binding bindingExchangeA(Queue aMessage,FanoutExchange fanoutExchange){
return BindingBuilder.bind(aMessage).to(fanoutExchange);
}
@Bean
Binding bindingExchangeB(Queue bMessage,FanoutExchange fanoutExchange){
return BindingBuilder.bind(bMessage).to(fanoutExchange);
}
}生产者和消费者
代码语言：javascript复制 /**
* fanoutExchange
*/
@RequestMapping("/fanout")
public void fanout() {
String fanout = "fanout";
rabbitTemplate.convertAndSend("fanoutExchange", "", fanout);
}
/**
* fanout
*/
@RabbitListener(queues = {"a_message"})
public void fanoutA(String message) {
System.out.println("fanout广播消费：" message);
}
@RabbitListener(queues = {"b_message"})
public void fanoutB(String message) {
System.out.println("fanout广播消费：" message);
}(完...)
