【第6章】Spring Cloud之Nacos服务调用(含RestTemplate 和 OpenFeign)

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前言

本章我们通过RestTemplate 和 OpenFeign来完成微服务中斲丧者对提供者服务的远程调用。

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一、准备

   这里我们在provider-service增长EchoService作为服务端，对外提供服务
  1. service

1. package org.example.nacos.provider.service;
3. /**
4. * Create by zjg on 2024/7/16
5. */
6. public interface EchoService {
7.     String echo(String str);
8. }

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1. package org.example.nacos.provider.service.impl;
3. import org.example.nacos.provider.service.EchoService;
4. import org.springframework.stereotype.Service;
6. /**
7. * Create by zjg on 2024/7/16
8. */
9. @Service
10. public class EchoServiceImpl implements EchoService {
11.     @Override
12.     public String echo(String str) {
13.         return "Hello "+str;
14.     }
15. }

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2. controller

1. package org.example.nacos.provider.controller;
3. import org.example.nacos.provider.service.EchoService;
4. import org.springframework.beans.factory.annotation.Autowired;
5. import org.springframework.web.bind.annotation.PathVariable;
6. import org.springframework.web.bind.annotation.RequestMapping;
7. import org.springframework.web.bind.annotation.RestController;
9. /**
10. * Create by zjg on 2024/7/16
11. */
12. @RestController
13. public class EchoController {
14.     @Autowired
15.     EchoService echoService;
16.     @RequestMapping("/echo/{str}")
17.     public String echo(@PathVariable("str")String str) {
18.         return echoService.echo(str);
19.     }
20. }

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二、RestTemplate

1. 打开开关

1. spring:
2.   cloud:
3.     loadbalancer:
4.       nacos:
5.         enabled: true

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2. 引入库

1. <dependency>
2.     <groupId>org.springframework.cloud</groupId>
3.     <artifactId>spring-cloud-starter-loadbalancer</artifactId>
4. </dependency>

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3. 设置负载均衡

1. package org.example.nacos.consumer.config;
3. import org.springframework.cloud.client.loadbalancer.LoadBalanced;
4. import org.springframework.context.annotation.Bean;
5. import org.springframework.context.annotation.Configuration;
6. import org.springframework.web.client.RestTemplate;
8. /**
9. * Create by zjg on 2024/7/16
10. */
11. @Configuration
12. public class ConsumerConfig {
13.     @Bean
14.     @LoadBalanced
15.     public RestTemplate restTemplate() {
16.         return new RestTemplate();
17.     }
18. }

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4. 测试类

1. package org.example.nacos.consumer.controller;
3. import org.springframework.beans.factory.annotation.Autowired;
4. import org.springframework.web.bind.annotation.GetMapping;
5. import org.springframework.web.bind.annotation.PathVariable;
6. import org.springframework.web.bind.annotation.RestController;
7. import org.springframework.web.client.RestTemplate;
9. /**
10. * Create by zjg on 2024/7/16
11. */
12. @RestController
13. public class TestController {
14.     @Autowired
15.     private RestTemplate restTemplate;
17.     @GetMapping(value = "/echo-rest/{str}")
18.     public String rest(@PathVariable("str") String str) {
19.         return restTemplate.getForObject("http://provider-service/echo/" + str, String.class);
20.     }
21. }

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localhost:9003/echo-rest/RestTemplate
   Hello RestTemplate
  三、FeignClient

1. 引入库

1. <dependency>
2.     <groupId>org.springframework.cloud</groupId>
3.     <artifactId>spring-cloud-starter-openfeign</artifactId>
4. </dependency>

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2. 打开开关

1. package org.example.nacos.consumer;
3. import org.springframework.boot.SpringApplication;
4. import org.springframework.boot.autoconfigure.SpringBootApplication;
5. import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
6. import org.springframework.cloud.openfeign.EnableFeignClients;
8. @EnableFeignClients
9. @EnableDiscoveryClient
10. @SpringBootApplication
11. public class NacosDiscoveryConsumerApplication {
13.     public static void main(String[] args) {
14.         SpringApplication.run(NacosDiscoveryConsumerApplication.class, args);
15.     }
17. }

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3. feign客户端

1. package org.example.nacos.consumer.feign;
3. import org.springframework.cloud.openfeign.FeignClient;
4. import org.springframework.web.bind.annotation.GetMapping;
5. import org.springframework.web.bind.annotation.PathVariable;
7. /**
8. * Create by zjg on 2024/7/16
9. */
10. @FeignClient(name = "provider-service")
11. public interface EchoClient {
12.     @GetMapping(value = "/echo/{str}")
13.     String echo(@PathVariable("str") String str);
14. }

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4. 测试类

1. package org.example.nacos.consumer.controller;
3. import org.example.nacos.consumer.feign.EchoClient;
4. import org.springframework.beans.factory.annotation.Autowired;
5. import org.springframework.web.bind.annotation.GetMapping;
6. import org.springframework.web.bind.annotation.PathVariable;
7. import org.springframework.web.bind.annotation.RestController;
9. /**
10. * Create by zjg on 2024/7/16
11. */
12. @RestController
13. public class TestController {
14.     @Autowired
15.     private EchoClient echoClient;
17.     @GetMapping(value = "/echo-feign/{str}")
18.     public String feign(@PathVariable("str") String str) {
19.         return echoClient.echo(str);
20.     }
21. }

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localhost:9003/echo-rest/OpenFeign
   Hello OpenFeign
  

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总结

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