add spring-rabbitmq example

Signed-off-by: Mohammad Sadegh Sheikh Zahedi <sheikhoo.iran@gmail.com>

spring-rabbitmq/backend/src/main/java/com/company/project/Application.java

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+package com.company.project;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class Application {
+
+    public static void main(String[] args) {
+        SpringApplication.run(Application.class, args);
+    }
+}

spring-rabbitmq/backend/src/main/java/com/company/project/config/QueueConsumer.java

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+package com.company.project.config;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.company.project.model.Message;
+import org.springframework.amqp.rabbit.core.RabbitTemplate;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.stereotype.Component;
+
+@Component
+public class QueueConsumer {
+
+    private final RabbitTemplate rabbitTemplate;
+
+    @Value("${queue.name}")
+    private String queueName;
+
+    @Autowired
+    public QueueConsumer(RabbitTemplate rabbitTemplate) {
+        this.rabbitTemplate = rabbitTemplate;
+    }
+
+    private String receiveMessage() {
+        String message = (String) rabbitTemplate.receiveAndConvert(queueName);
+        return message;
+    }
+
+    public Message processMessage() throws JsonProcessingException {
+        String message = receiveMessage();
+        return new ObjectMapper().readValue(message, Message.class);
+    }
+}

spring-rabbitmq/backend/src/main/java/com/company/project/config/QueueProducer.java

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+package com.company.project.config;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.company.project.model.Message;
+import org.springframework.amqp.rabbit.core.RabbitTemplate;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.stereotype.Component;
+
+@Component
+public class QueueProducer {
+
+    @Value("${fanout.exchange}")
+    private String fanoutExchange;
+
+    private final RabbitTemplate rabbitTemplate;
+
+    @Autowired
+    public QueueProducer(RabbitTemplate rabbitTemplate) {
+        this.rabbitTemplate = rabbitTemplate;
+    }
+
+    public void produce(Message message) throws JsonProcessingException {
+
+        rabbitTemplate.setExchange(fanoutExchange);
+        rabbitTemplate.convertAndSend(new ObjectMapper().writeValueAsString(message));
+    }
+}

spring-rabbitmq/backend/src/main/java/com/company/project/config/RabbitConfiguration.java

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+package com.company.project.config;
+
+import org.springframework.amqp.core.Binding;
+import org.springframework.amqp.core.BindingBuilder;
+import org.springframework.amqp.core.FanoutExchange;
+import org.springframework.amqp.core.Queue;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration
+public class RabbitConfiguration {
+    @Value("${fanout.exchange}")
+    private String fanoutExchange;
+
+    @Value("${queue.name}")
+    private String queueName;
+
+    @Bean
+    Queue queue() {
+        return new Queue(queueName, true);
+    }
+
+    @Bean
+    FanoutExchange fanoutExchange() {
+        return new FanoutExchange(fanoutExchange);
+    }
+
+    @Bean
+    Binding binding(Queue queue, FanoutExchange fanoutExchange) {
+        return BindingBuilder.bind(queue).to(fanoutExchange);
+    }
+}

spring-rabbitmq/backend/src/main/java/com/company/project/controller/MessageController.java

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+package com.company.project.controller;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.company.project.config.QueueConsumer;
+import com.company.project.config.QueueProducer;
+import com.company.project.model.Message;
+
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.stereotype.Controller;
+import org.springframework.web.bind.annotation.*;
+
+@Controller
+@RequestMapping("/")
+public class MessageController {
+
+    private final QueueProducer queueProducer;
+    private final QueueConsumer queueConsumer;
+
+    public MessageController(QueueProducer queueProducer, QueueConsumer queueConsumer) {
+        this.queueProducer = queueProducer;
+        this.queueConsumer = queueConsumer;
+    }
+
+    @GetMapping("getMessage")
+    public ResponseEntity<?> getMessage() throws JsonProcessingException {
+        Message message = queueConsumer.processMessage();
+        return new ResponseEntity<Message>(message, HttpStatus.OK);
+    }
+
+    @PostMapping("sendMessage")
+    public ResponseEntity<?> sendMessage(@RequestBody Message message) throws JsonProcessingException {
+        queueProducer.produce(message);
+        return new ResponseEntity<Message>(HttpStatus.CREATED);
+    }
+}

spring-rabbitmq/backend/src/main/java/com/company/project/model/Message.java

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+package com.company.project.model;
+
+public class Message {
+
+    private String title;
+    private String text;
+    private String sender;
+
+    public String getTitle() {
+        return title;
+    }
+
+    public void setTitle(String title) {
+        this.title = title;
+    }
+
+    public String getText() {
+        return text;
+    }
+
+    public void setText(String text) {
+        this.text = text;
+    }
+
+    public String getSender() {
+        return sender;
+    }
+
+    public void setSender(String sender) {
+        this.sender = sender;
+    }
+}

spring-rabbitmq/backend/src/main/resources/application.properties

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+server.port= 8080
+spring.main.banner-mode= off
+spring.rabbitmq.host= ${RABBITMQ_HOST:localhost}
+spring.rabbitmq.port= 5672
+spring.rabbitmq.username= guest
+spring.rabbitmq.password= guest
+queue.name= ${RABBITMQ_QUEUE_NAME:springboot-queue}
+fanout.exchange= ${RABBITMQ_FANOUT_EXCHANGE:springboot-exchange}
+