springcloud feign用法

我们将一个复杂的业务，拆解成了多个微服务，但微服务中间还需要互相访问才对，springcloud给我们提供了feign，可以很好的解决微服务之间的访问问题，并且还支持负载均衡、熔断等特性，微服务注册到eureka中以后，我们只需要关注服务接口，不需要知道服务来自哪里，服务的ip、端口是什么，这对我们应用架构部署来说，真是个福音。

使用feign非常简单，下面详细介绍下过程。

创建一个springboot工程，pom如下

<?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.liusx</groupId>
	<artifactId>feign-auth</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>jar</packaging>

	<name>feign-auth</name>
	<description>Demo project for Spring Boot</description>

	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>1.5.10.RELEASE</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>

	<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
		<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
		<java.version>1.8</java.version>
		<spring-cloud.version>Edgware.SR1</spring-cloud.version>
	</properties>

	<dependencies>
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-eureka</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-feign</artifactId>
		</dependency>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
	</dependencies>

	<dependencyManagement>
		<dependencies>
			<dependency>
				<groupId>org.springframework.cloud</groupId>
				<artifactId>spring-cloud-dependencies</artifactId>
				<version>${spring-cloud.version}</version>
				<type>pom</type>
				<scope>import</scope>
			</dependency>
		</dependencies>
	</dependencyManagement>

	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>


</project>

修改启动类

@SpringBootApplication
@EnableFeignClients
public class FeignAuthApplication {

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

修改application.yml

spring:
  application:
    name: liusx-feign-auth
server:
  port: 9081

eureka:
  instance:
    hostname: 127.0.0.1
    prefer-ip-address: true
    instance-id: ${spring.cloud.client.ipAddress}:${server.port}
  client:
    register-with-eureka: false
    fetch-registry: true
    serviceUrl:
      defaultZone: http://user:123456@${eureka.instance.hostname}:8761/eureka/  #注册 中心已经开启认证

创建service，访问来自liusx-servers-auth中的auth/login服务

package com.liusx.feign.auth.service;

import org.springframework.cloud.netflix.feign.FeignClient;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;

@FeignClient(value = "liusx-servers-auth")
public interface IAccountService {

    @RequestMapping(value = "/auth/login", method = RequestMethod.POST)
    String login(@RequestParam("userName") String userName,
                 @RequestParam("password") String password);
}

创建controller，在controller中，我们访问service的login方法，而在service中，具体login实现其实是来自liusx-servers-auth服务

package com.liusx.feign.auth.controller;

import com.liusx.feign.auth.service.IAccountService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class AccountController {

    @Autowired
    IAccountService accountService;

    @PostMapping("/login")
    public String login(String userName, String password) {
        return accountService.login(userName, password);
    }
}

工程创建到这里已经结束，测试下看看对不对，启动liusx-servers-eureka、liusx-servers-auth、liusx-feign-auth3个工程

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访问地址 http://localhost:9081/login ，可以看到已经成功拿到返回值了

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springcloud feign用法

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