Spring Cloud(Finchley.RCI) (四) Spring Cloud创建服务消费者(Ribbon)

在微服务架构中, 业务都会被拆分成一个独立的服务, 服务与服务的通讯是基于http restful的, Spring Cloud有两种服务调用方式, 一种是ribbon+restTemplate, 另一种是feign.

Ribbon简介

Ribbon是一个负载均衡客户端, 可以很好的控制http和tcp的一些行为。

准备工作

启动服务提供者, 端口号为: 8762

修改配置文件的端口号为: 8763, 启动后再Eureka中会注册两个实例, 相当于一个小集群

创建服务消费者

创建一个工程名为: hello-spring-cloud-web-admin-ribbon的服务消费者项目, pol.xml配置如下:

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>com.funtl</groupId>
        <artifactId>hello-spring-cloud-dependencies</artifactId>
        <version>1.0.0-SNAPSHOT</version>
        <relativePath>../hello-spring-cloud-dependencies/pom.xml</relativePath>
    </parent>

    <artifactId>hello-spring-cloud-web-admin-ribbon</artifactId>
    <packaging>jar</packaging>

    <name>hello-spring-cloud-web-admin-ribbon</name>
    <url>http://www.funtl.com</url>
    <inceptionYear>2018-Now</inceptionYear>

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

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</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-netflix-eureka-server</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
        </dependency>

        <dependency>
            <groupId>net.sourceforge.nekohtml</groupId>
            <artifactId>nekohtml</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <mainClass>com.funtl.hello.spring.cloud.web.admin.ribbon.WebAdminRibbonApplication</mainClass>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

主要是增加了Ribbon的依赖

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
</dependency>

Application

通过@EnableDiscoveryClient注解注册到服务中心

package com.funtl.hello.spring.cloud.web.admin.ribbon;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;

@EnableDiscoveryClient
@SpringBootApplication
public class WebAdminRibbonApplication {
    public static void main(String[] args) {
        SpringApplication.run(WebAdminRibbonApplication.class, args);
    }
  

application.yml

设置程序端口号为: 8764

spring:
  application:
    name: hello-spring-cloud-web-admin-ribbon
  thymeleaf:
    cache: false
    mode: LEGACYHTML5
    encoding: UTF-8
    servlet:
      content-type: text/html
server:
  port: 8764
eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/

Configuration

配置注入RestTemplate的Bean, 并通过@LoadBalanced注解表明开启负载均衡功能

package com.funtl.hello.spring.cloud.web.admin.ribbon.config;

import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.client.RestTemplate;

@Configuration
public class RestTemplateConfiguration {
    @Bean
    @LoadBalanced
    public RestTemplate restTemplate(){
        return new RestTemplate();
    }
}

创建测试用的Service

package com.funtl.hello.spring.cloud.web.admin.ribbon.service;

import com.netflix.discovery.converters.Auto;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;

@Service
public class AdminService {
    @Autowired
    private RestTemplate restTemplate;

    public String sayHi(String message){
        return restTemplate.getForObject("http://hello-spring-cloud-service-admin/hi?message="+message, String.class);
    }
}

创建测试用的Controller

package com.funtl.hello.spring.cloud.web.admin.ribbon.controller;

import com.funtl.hello.spring.cloud.web.admin.ribbon.service.AdminService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class AdminController {

    @Autowired
    private AdminService adminService;

    @RequestMapping(value="hi", method= RequestMethod.GET)
    public String sayHi(String message){
        return adminService.sayHi(message);
    }
}

测试访问

在浏览器上多次访问http://localhost:8764/hi?message=HelloRibbon