如何使用 Apache Camel 处理restApi ？

简介：
在这篇文章中，我们将学习基本结构以及如何处理API调用并将其路由到RabbitMQ。我们将创建一个maven项目，在该项目中我们将处理这一场景。

项目的Maven结构。

pom.xml如下所示

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.6.8</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>
	<groupId>com.camel</groupId>
	<artifactId>ApacheCamel</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>ApacheCamel</name>
	<description>Demo project for Spring Boot to consume from rabbit and      publish to kafka</description>
	<properties>
		<java.version>11</java.version>
	</properties>
	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>

		<dependency>
			<groupId>org.projectlombok</groupId>
			<artifactId>lombok</artifactId>
			<optional>true</optional>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
<!--Camel Dependencies		-->
		<dependency>
			<groupId>org.apache.camel</groupId>
			<artifactId>camel-spring-boot-starter</artifactId>
			<version>2.17.0</version>
		</dependency>

		<dependency>
			<groupId>org.apache.camel</groupId>
			<artifactId>camel-core</artifactId>
			<version>2.17.0</version>
		</dependency>
		<dependency>
			<groupId>org.apache.camel</groupId>
			<artifactId>camel-jackson</artifactId>
			<version>2.17.0</version>
		</dependency>
		<dependency>
			<groupId>org.apache.camel</groupId>
			<artifactId>camel-rabbitmq</artifactId>
			<version>2.17.0</version>
		</dependency>
	</dependencies>

	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
				<configuration>
					<excludes>
						<exclude>
							<groupId>org.projectlombok</groupId>
							<artifactId>lombok</artifactId>
						</exclude>
					</excludes>
				</configuration>
			</plugin>
		</plugins>
	</build>

</project>

创建一个模型类：
这里我使用 Lombok 以避免模板代码。

package com.camel.ApacheCamel.model;

import lombok.*;

/**
 * Model class to Process the Library Book details.
 *
 */
@Builder
@NoArgsConstructor
@AllArgsConstructor
@Getter
@Setter
public class LibraryBookDetail {
    private int serialNo;
    private String bookName;
    private String autherName;
    private double price;
}

定义Camel路线。

• 我们需要将libraryBookDetail对象编入JSON。为此，我们将使用Apache Camel JacksonDataFormat。
• 创建骆驼路线，将雇员对象编入，然后将其发送到名为libraryQueue的rabbitmq队列中。同时，创建一个名为libraryQueue.Exchange的rabbitmq交易所。

package com.camel.ApacheCamel.route;

import com.camel.ApacheCamel.model.LibraryBookDetail;
import org.apache.camel.builder.RouteBuilder;
import org.apache.camel.component.jackson.JacksonDataFormat;
import org.springframework.stereotype.Component;

/**
 * This class is use to Route the Data to RabbitMQ
 * which is recieved from Rest call.
 */
@Component
public class LibraryRoute extends RouteBuilder {
    @Override
    public void configure() throws Exception {
        JacksonDataFormat jacksonDataFormat = new JacksonDataFormat(LibraryBookDetail.class);
        from("direct:restPointCall").id("idToRouteRest").marshal(jacksonDataFormat)
                .to("rabbitmq://localhost:5672/librayQueue.exchange?queue=librayQueue&autoDelete=false").end();
    }
}

创建控制器。

• 暴露GET REST API以获取librarybookdetail参数
• 使用 Camel ProducerTemplate 将 librarybookdetail 对象发送到 RabbitMQ Queueue。

package com.camel.ApacheCamel.controller;

import com.camel.ApacheCamel.model.LibraryBookDetail;
import org.apache.camel.Produce;
import org.apache.camel.ProducerTemplate;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class LibraryController {

    @Produce(uri = "direct:restPointCall")
    private ProducerTemplate producerTemplate;

    /**
     *
     * @param serialNo
     * @param bookName
     * @param autherName
     * @param price
     * This call receive the Book Detail using rest call and forward it to rabbitMQ queue.
     * @return Simple message "Processed Successfully"
     */
    @GetMapping(value = "/enterbookdetail")
    public String enterBookDetailToLibrary(@RequestParam("serialNo") int serialNo, @RequestParam("bookName") String bookName, @RequestParam("autherName") String autherName, @RequestParam("price") Double price) {
        LibraryBookDetail bookDetail = LibraryBookDetail.builder().serialNo(serialNo)
                .bookName(bookName)
                .autherName(autherName)
                .price(price)
                .build();
        producerTemplate.asyncSendBody(producerTemplate.getDefaultEndpoint(), bookDetail);
        return "Processed Successfully";
    }
}

最后，使用 SpringBootApplication 注解创建 bootstrap 类。

package com.camel.ApacheCamel;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class ApacheCamelApplication {

	public static void main(String[] args) {
		SpringApplication.run(ApacheCamelApplication.class, args);
	}

}

结论

在这篇文章中，我们已经了解了 restApi 调用的简单流程，并使用 Apache Camel 对其进行了处理，并将此 Rest Call 发送到 RabbitMQ，以便我们的内部或外部服务能够使用这些数据。