Spring Cloud Alibaba-Nacos-创建服务消费者

灰太狼 2020-05-18 16:19 1433阅读 0赞

# Spring Cloud Alibaba-Nacos-创建服务消费者

## 概述

服务消费者的创建与服务提供者大同小异，这里采用最原始的一种方式，即显示的使用 LoadBalanceClient 和 RestTemplate 结合的方式来访问。

## POM

创建一个工程名为 `hello-spring-cloud-alibaba-nacos-consumer` 的服务消费者项目，`pom.xml` 配置如下：

```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>

<parent>
        <groupId>cn.dandelioncloud</groupId>
        <artifactId>hello-spring-cloud-alibaba-dependencies</artifactId>
        <version>1.0.0-SNAPSHOT</version>
        <relativePath>../hello-spring-cloud-alibaba-dependencies/pom.xml</relativePath>
    </parent>

<artifactId>hello-spring-cloud-alibaba-nacos-consumer</artifactId>
    <packaging>jar</packaging>

<name>hello-spring-cloud-alibaba-nacos-consumer</name>
    <url>http://www.dandelioncloud.cn</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-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-alibaba-nacos-discovery</artifactId>
        </dependency>
        
    </dependencies>

<build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <mainClass>cn.dandelioncloud.hello.spring.cloud.alibaba.nacos.consumer.NacosConsumerApplication</mainClass>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>
```

## Application

```java
package cn.dandelioncloud.hello.spring.cloud.alibaba.nacos.consumer;

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

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

## Configuration

创建一个名为 `NacosConsumerConfiguration` 的 Java 配置类，主要作用是为了注入 `RestTemplate`

```java
package cn.dandelioncloud.hello.spring.cloud.alibaba.nacos.consumer.config;

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

@Configuration
public class NacosConsumerConfiguration {

@Bean
    public RestTemplate restTemplate() {
        return new RestTemplate();
    }
}
```

## Controller

创建一个名为 `NacosConsumerController` 测试用的 Controller

```java
package cn.dandelioncloud.hello.spring.cloud.alibaba.nacos.consumer.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.loadbalancer.LoadBalancerClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

@RestController
public class NacosConsumerController {

@Autowired
    private LoadBalancerClient loadBalancerClient;

@Autowired
    private RestTemplate restTemplate;

@Value("${spring.application.name}")
    private String appName;

@GetMapping(value = "/echo/app/name")
    public String echo() {
        //使用 LoadBalanceClient 和 RestTemplate 结合的方式来访问
        ServiceInstance serviceInstance = loadBalancerClient.choose("nacos-provider");
        String url = String.format("http://%s:%s/echo/%s", serviceInstance.getHost(), serviceInstance.getPort(), appName);
        return restTemplate.getForObject(url, String.class);
    }
}
```

## application.yml

```yaml
spring:
  application:
    name: nacos-consumer
  cloud:
    nacos:
      discovery:
        server-addr: 127.0.0.1:8848

server:
  port: 9091

management:
  endpoints:
    web:
      exposure:
        include: "*"
```

## 启动工程

通过浏览器访问 `http://localhost:8848/nacos`，即 Nacos Server 网址

![](/images/1589818734224.png)

你会发现多了一个名为 `nacos-consumer` 的服务

这时打开 `http://localhost:9091/echo/app/name` ，你会在浏览器上看到：

```html
Hello Nacos Discovery nacos-consumer
```

## 服务的端点检查

通过浏览器访问 `http://localhost:9091/actuator/nacos-discovery` 你会在浏览器上看到：