Spring Cloud Alibaba-Nacos-创建服务消费者

男娘i 2024-03-30 12:25 73阅读 0赞

### 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：

> 1.  `<?xml version="1.0" encoding="UTF-8"?>`
> 2.  `<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"`
> 3.  `xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">`
> 4.  `<modelVersion>4.0.0</modelVersion>`
> 5.  
> 6.  `<parent>`
> 7.  `<groupId>cn.dandelioncloud</groupId>`
> 8.  `<artifactId>hello-spring-cloud-alibaba-dependencies</artifactId>`
> 9.  `<version>1.0.0-SNAPSHOT</version>`
> 10. `<relativePath>../hello-spring-cloud-alibaba-dependencies/pom.xml</relativePath>`
> 11. `</parent>`
> 12. 
> 13. `<artifactId>hello-spring-cloud-alibaba-nacos-consumer</artifactId>`
> 14. `<packaging>jar</packaging>`
> 15. 
> 16. `<name>hello-spring-cloud-alibaba-nacos-consumer</name>`
> 17. `<url>http://www.dandelioncloud.cn</url>`
> 18. `<inceptionYear>2018-Now</inceptionYear>`
> 19. 
> 20. `<dependencies>`
> 21. ``
> 22. `<dependency>`
> 23. `<groupId>org.springframework.boot</groupId>`
> 24. `<artifactId>spring-boot-starter-web</artifactId>`
> 25. `</dependency>`
> 26. `<dependency>`
> 27. `<groupId>org.springframework.boot</groupId>`
> 28. `<artifactId>spring-boot-starter-actuator</artifactId>`
> 29. `</dependency>`
> 30. `<dependency>`
> 31. `<groupId>org.springframework.boot</groupId>`
> 32. `<artifactId>spring-boot-starter-test</artifactId>`
> 33. `<scope>test</scope>`
> 34. `</dependency>`
> 35. ``
> 36. 
> 37. ``
> 38. `<dependency>`
> 39. `<groupId>org.springframework.cloud</groupId>`
> 40. `<artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>`
> 41. `</dependency>`
> 42. ``
> 43. `</dependencies>`
> 44. 
> 45. `<build>`
> 46. `<plugins>`
> 47. `<plugin>`
> 48. `<groupId>org.springframework.boot</groupId>`
> 49. `<artifactId>spring-boot-maven-plugin</artifactId>`
> 50. `<configuration>`
> 51. `<mainClass>cn.dandelioncloud.hello.spring.cloud.alibaba.nacos.consumer.NacosConsumerApplication</mainClass>`
> 52. `</configuration>`
> 53. `</plugin>`
> 54. `</plugins>`
> 55. `</build>`
> 56. `</project>`

### Application ###

> 1.  `package cn.dandelioncloud.hello.spring.cloud.alibaba.nacos.consumer;`
> 2.  
> 3.  `import org.springframework.boot.SpringApplication;`
> 4.  `import org.springframework.boot.autoconfigure.SpringBootApplication;`
> 5.  `import org.springframework.cloud.client.discovery.EnableDiscoveryClient;`
> 6.  
> 7.  `@SpringBootApplication`
> 8.  `@EnableDiscoveryClient`
> 9.  `public class NacosConsumerApplication {`
> 10. `public static void main(String[] args) {`
> 11. `SpringApplication.run(NacosConsumerApplication.class, args);`
> 12. `}`
> 13. `}`

### Configuration ###

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

> 1.  `package cn.dandelioncloud.hello.spring.cloud.alibaba.nacos.consumer.config;`
> 2.  
> 3.  `import org.springframework.context.annotation.Bean;`
> 4.  `import org.springframework.context.annotation.Configuration;`
> 5.  `import org.springframework.web.client.RestTemplate;`
> 6.  
> 7.  `@Configuration`
> 8.  `public class NacosConsumerConfiguration {`
> 9.  
> 10. `@Bean`
> 11. `public RestTemplate restTemplate() {`
> 12. `return new RestTemplate();`
> 13. `}`
> 14. `}`

### Controller ###

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

> 1.  `package cn.dandelioncloud.hello.spring.cloud.alibaba.nacos.consumer.controller;`
> 2.  
> 3.  `import org.springframework.beans.factory.annotation.Autowired;`
> 4.  `import org.springframework.beans.factory.annotation.Value;`
> 5.  `import org.springframework.cloud.client.ServiceInstance;`
> 6.  `import org.springframework.cloud.client.loadbalancer.LoadBalancerClient;`
> 7.  `import org.springframework.web.bind.annotation.GetMapping;`
> 8.  `import org.springframework.web.bind.annotation.RestController;`
> 9.  `import org.springframework.web.client.RestTemplate;`
> 10. 
> 11. `@RestController`
> 12. `public class NacosConsumerController {`
> 13. 
> 14. `@Autowired`
> 15. `private LoadBalancerClient loadBalancerClient;`
> 16. 
> 17. `@Autowired`
> 18. `private RestTemplate restTemplate;`
> 19. 
> 20. `@Value("${spring.application.name}")`
> 21. `private String appName;`
> 22. 
> 23. `@GetMapping(value = "/echo/app/name")`
> 24. `public String echo() {`
> 25. `//使用 LoadBalanceClient 和 RestTemplate 结合的方式来访问`
> 26. `ServiceInstance serviceInstance = loadBalancerClient.choose("nacos-provider");`
> 27. `String url = String.format("http://%s:%s/echo/%s", serviceInstance.getHost(), serviceInstance.getPort(), appName);`
> 28. `return restTemplate.getForObject(url, String.class);`
> 29. `}`
> 30. `}`

### application.yml ###

> 1.  `spring:`
> 2.  `application:`
> 3.  `name: nacos-consumer`
> 4.  `cloud:`
> 5.  `nacos:`
> 6.  `discovery:`
> 7.  `server-addr: 127.0.0.1:8848`
> 8.  
> 9.  `server:`
> 10. `port: 9091`
> 11. 
> 12. `management:`
> 13. `endpoints:`
> 14. `web:`
> 15. `exposure:`
> 16. `include: "*"`

### 启动工程 ###

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

![7f0287cad2794a08ae2bd54683c00785.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：

> 1.  `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：

![c8cb1d53653145209a10d7a0aa2baaa2.png][]

[7f0287cad2794a08ae2bd54683c00785.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/30/b923dc6348a844a8881f8eb29bf92e1c.png
[c8cb1d53653145209a10d7a0aa2baaa2.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/30/11d5d4cad3b94dfdb9d4ca558faa9496.png