Spring Cloud 之 Feign

新建Spring Boot工程,命名为feign

1.pom.xml添加依赖

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

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

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.9.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>
    </properties>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Edgware.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

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

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

    <repositories>
        <repository>
            <id>spring-milestones</id>
            <name>Spring Milestones</name>
            <url>https://repo.spring.io/milestone</url>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
    </repositories>
</project>

2.将application.properties重命名为application.yml,并且添加配置

spring:
  application:
    name: feign
server:
  port: 8766
eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/

3.启动类代码

添加@EnableFeignClients注解

package com.dzpykj;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.netflix.feign.EnableFeignClients;

@SpringBootApplication
@EnableFeignClients
@EnableEurekaClient
public class FeignApplication {

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

4.新建一个Feign的接口

package com.dzpykj.feignInterface;

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

@FeignClient(value = "eurekaclient") //value为要负载均衡的spring.application.name
public interface HelloInterface {

    @RequestMapping("/hi") //负载均衡目标工程里面的哪个方法
    public String hello(@RequestParam(value="name") String name);
}

5.新建一个Controller

package com.dzpykj.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import com.dzpykj.feignInterface.HelloInterface;

@RestController
public class HelloController {

    @Autowired
    HelloInterface helloInterface;

    @RequestMapping("/hello/{name}")
    public String hello(@PathVariable String name) {
        return helloInterface.hello(name);
    }
}

6.依次启动Eureka服务集群、Eureka客户端集群、Feign工程

6.1 按照Spring Cloud Eureka Server集群Demo级搭建的步骤启动Eureka服务peer1,peer2集群

6.2按照Spring Cloud Eureka服务Demo级搭建最后面的步骤,分别启动8763,8764两个Eureka客户端形成集群

6.3启动Feign工程

7.准备工作完成,开始访问测试

访问路径:http://127.0.0.1:8766/hello/chaixy,多次访问,会发现这些请求是在Eureka客户端集群8763和8764之间交替访问