OpenFeign是一個Web聲明式的Http客戶端調用工具,提供接口和註解形式調用。開發微服務,免不了需要服務間調用。Spring Cloud框架提供了RestTemplate和FeignClient兩個方式完成服務間調用,本文簡要介紹如何使用OpenFeign完成服務間調用,下面開始進行整合:
首先基於IDEA建立maven聚合項目如下圖:
其中,springcloud-alibaba-parent是父項目,存放一些共同依賴,service-api,service-impl是springcloud-alibaba-parent的module子模塊,service-api-member,service-api-order是service-api的module子模塊,service-impl-member,service-impl-order是service-impl的module子模塊。
在springcloud-alibaba-parent引入如下公共依賴:
<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.xyy</groupId>
<artifactId>springcloud-alibaba-parent</artifactId>
<packaging>pom</packaging>
<version>1.0-SNAPSHOT</version>
<modules>
<module>service-api</module>
<module>service-impl</module>
</modules>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.0.RELEASE</version>
</parent>
<dependencies>
<!-- springboot 整合web組件-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
<version>0.2.2.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-openfeign</artifactId>
<version>2.0.0.RELEASE</version>
</dependency>
</dependencies>
</project>
service-impl-member依賴如下:
<dependencies>
<dependency>
<groupId>com.xyy</groupId>
<artifactId>service-api-member</artifactId>
<version>1.0-SNAPSHOT</version>
</dependency>
</dependencies>
service-impl-order依賴如下:
<dependencies>
<dependency>
<groupId>com.xyy</groupId>
<artifactId>service-api-member</artifactId>
<version>1.0-SNAPSHOT</version>
</dependency>
<dependency>
<groupId>com.xyy</groupId>
<artifactId>service-api-order</artifactId>
<version>1.0-SNAPSHOT</version>
</dependency>
</dependencies>
service-impl-member配置文件如下:
spring:
application:
# 服務名稱
name: service-member
cloud:
nacos:
discovery:
# nacos註冊地址
server-addr: 127.0.0.1:8848
server:
port: 8081
service-impl-order配置文件如下:
spring:
application:
# 服務名稱
name: service-order
cloud:
nacos:
discovery:
# nacos註冊地址
server-addr: 127.0.0.1:8848
server:
port: 8090
在service-api-member編寫Member服務:
package com.xyy;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
public interface MemberService {
/**
* 提供我們發佈的接口
* @param userId
* @return
*/
@GetMapping("/getUser")
String getUser(@RequestParam("userId") Integer userId);
}
在service-impl-member編寫實現類:
package com.xyy.impl;
import com.xyy.MemberService;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.RestController;
@RestController
public class MemberServiceImpl implements MemberService {
@Value("${server.port}")
private String serverPort;
@Override
public String getUser(Integer userId) {
return "我是會員服務" + serverPort;
}
}
在service-impl-order編寫openFeign客戶端(直接實現會員服務接口即可):
package com.xyy.openfeign;
import com.xyy.MemberService;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
@FeignClient("service-member")
public interface MemberServiceFeign extends MemberService {
}
在service-impl-order編寫訂單實現:
package com.xyy.impl;
import com.xyy.openfeign.MemberServiceFeign;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
@RestController
public class OrderService {
@Autowired
private MemberServiceFeign memberServiceFeign;
/**
* 基於我們的feign客戶端形式實現rpc遠程調用
* @return
*/
@RequestMapping("/orderFeignToMember")
public String orderFeignToMember() {
String result = memberServiceFeign.getUser(1);
return "我是訂單服務調用會員服務的接口,返回結果" + result;
}
}
分別啓動service-impl-member(8080),service-impl-member(8081),service-impl-order(8090),直接請求orderFeignToMember接口,會發現,底層默認封裝了Ribbon進行客戶端負載均衡:
【小結】:
· 訂單調會員的時候,會員服務接口的方法參數,一定要加@RequestParam註解,訂單可以不用加。
· 在微服務架構中Nacos服務的名稱命名不能夠有下劃線(service_order是錯誤寫法,openfeign調用的時候報錯)。