SpringAli服务消费

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微服务改变着我们的项目结构,影响深远

Spring Cloud Alibaba 服务消费

  1. 服务消费(原始方式)
  2. 服务消费(使用Feign)

服务消费(原始方式)

显示的使用 LoadBalanceClient 和 RestTemplate 结合的方式来访问。

创建新的moudle模块(消费者),pom.xml如下

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<?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">
    <parent>
        <artifactId>cloud-dependencies</artifactId>
        <groupId>com.wwj</groupId>
        <version>1.0-SNAPSHOT</version>
        <relativePath>../pom.xml</relativePath>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>nacos-consumer</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-actuator</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-alibaba-nacos-discovery</artifactId>
        </dependency>
        <!-- Spring Cloud End -->
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <mainClass>com.wwj.consumer.ConsumerApplication</mainClass>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

安装标准构建启动类

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

}

构建一个ConsumerConfiguration配置类,注入RestTemplate对象

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

编写controller

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package com.wwj.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 ConsumerController {
    //注入启动客户端对象
    @Autowired
    private LoadBalancerClient loadBalancerClient;
    //注入RestTemplate模板
    @Autowired
    private RestTemplate restTemplate;
    //可以用来获取当前应用名称
    @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
        //选择服务名字
        ServiceInstance serviceInstance = loadBalancerClient.choose("provider");
        //拼接restful请求
        String url = String.format("http://%s:%s/echo/%s", serviceInstance.getHost(), serviceInstance.getPort(), appName);
        return restTemplate.getForObject(url, String.class);
    }
}

构建应用程序启动文件 application.yml

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

server:
  port: 9091

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

结果如下

IMAGE

端点检查 http://localhost:9091/actuator/nacos-discovery

IMAGE

服务消费(使用Feign)

概论

Feign 是一个声明式的伪 Http 客户端，它使得写 Http 客户端变得更简单。使用 Feign，只需要创建一个接口并注解。它具有可插拔的注解特性，可使用 Feign 注解和 JAX-RS 注解。Feign 支持可插拔的编码器和解码器。Feign 默认集成了 Ribbon，Nacos 也很好的兼容了 Feign，默认实现了负载均衡的效果

  1. 使用接口很容易抽象理解
  2. 集成Ribbon达到负载均衡

构建新的moudle,pom.xml内容如下

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<?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">
    <parent>
        <artifactId>cloud-dependencies</artifactId>
        <groupId>com.wwj</groupId>
        <version>1.0-SNAPSHOT</version>
        <relativePath>../pom.xml</relativePath>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>nacos-consumer-feign</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-actuator</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-alibaba-nacos-discovery</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>
        <!-- Spring Cloud End -->
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <mainClass>com.wwj.consumer.feign.ConsumerFeignApplication</mainClass>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

构建启动类

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

通过feign调用远程服务

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/**
 * 1.通过@FeignClient伪造一个http客户端请求已经注册的服务
 * 2.接口中的方法需要去匹配已经注册的服务方里面的请求
 */

@FeignClient(value = "nacos-provider")
public interface ProviderService {

    @GetMapping(value = "/echo/{message}")
    String echo(@PathVariable String message);
}

controller注入对应的服务

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@RestController
public class ProviderController {

    @Autowired
    private ProviderService providerService;

    @GetMapping("echo")
    public String echo() {
        return providerService.echo("Feign Client");
    }
}

全局配置文件声明如下

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

server:
  port: 9092

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

结果如下

IMAGE

测试负载均衡

  1. 服务端启动多个示例
  2. 多次访问localhost:9092/echo

IMAGE

IMAGE