spring cloud netflix (06) 服務的消費者(Ribbon+RestTemplate)

前言

完整知識點：spring cloud netflix 系列技術棧
Ribbon+RestTemplate (同步通信 HTTP通信)

搭建Ribbon服務

項目結構

項目搭建

• pom.xml

<?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>
    <!-- 關聯統一的依賴管理 -->
    <parent>
        <groupId>com.baiyang</groupId>
        <artifactId>spring-cloud-netflix-dependencies</artifactId>
        <version>1.0.0-SNAPSHOT</version>
        <!-- 指向統一的依賴管理的位置 -->
        <relativePath>../spring-cloud-netflix-dependencies/pom.xml</relativePath>
    </parent>

    <groupId>com.baiyang</groupId>
    <artifactId>spring-cloud-netflix-web-admin-ribbon</artifactId>
    <packaging>jar</packaging>

    <dependencies>
        <!-- Spring Boot Begin -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</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-test</artifactId>
            <scope>test</scope>
        </dependency>
        <!-- Spring Boot End -->

        <!-- Spring Cloud Begin -->
        <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>
        <!-- Spring Cloud End -->

        <!-- 解決 thymeleaf 模板引擎一定要執行嚴格的 html5 格式校驗問題 -->
        <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>
                    <!-- 配置程序的入口類 -->
                    <mainClass>com.baiyang.spring.cloud.netflix.web.admin.ribbon.AdminWebRibbonApplication</mainClass>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

• application類

package com.baiyang.spring.cloud.netflix.web.admin.ribbon;

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

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

• application.yml

spring:
  application:
    # 項目名稱
    name: spring-cloud-netflix-web-admin-ribbon

server:
  port: 8764

# 註冊到eureka註冊中心
eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/

thymeleaf:
    cache: false
    mode: LEGACYHTML5
    encoding: UTF-8
    servlet:
      content-type: text/html

• RestTemplate

package com.baiyang.spring.cloud.netflix.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 {

    /**
     * <p>eureka ribbon 模式下 服務提供者與服務消費者之間的通信工具</p>
     * <p>可配置負載均衡的能力</p>
     * <p>爲RestTemplate開啓負載均衡策略</p>
     * @return
     */
    @Bean
    @LoadBalanced
    public RestTemplate restTemplate(){
        return new RestTemplate();
    }
}

使用ribbon+RestTemplate實現服務與服務之間的通信

ribbon是服務的消費者，通信便是指與服務提供者完成信息傳遞。
核心方法：getForObject(url,class);

package com.baiyang.spring.cloud.netflix.web.admin.ribbon.service;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;

@Service
public class AdminWebRibbonService {

    @Autowired
    private RestTemplate restTemplate;

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