使用 RestTemplate 结合 Ribbon 实现服务调用

https://www.bilibili.com/video/BV1AN411Z7mx?p=14

MyConfig.java

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 MyConfig {

    // 如果希望使用 Ribbon 的负载均衡能力
    @Bean
    @LoadBalanced
    public RestTemplate restTemplate() {
        return new RestTemplate();
    }
    
}

ClientServiceImpl.java

import io.github.jihch.service.ClientService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.loadbalancer.LoadBalancerClient;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;

@Service
public class ClientServiceImpl implements ClientService {

    // Ribbon 的负载均衡工具。使用这个对象的时候可以使用 Ribbon 的功能
    @Autowired
    private LoadBalancerClient loadBalancerClient;

    @Autowired
    private RestTemplate restTemplate;


    @Override
    public String client() {
        String result = restTemplate.getForObject("http://myproject/demo", String.class);
        return result;
    }


}

stop all Application Service 实例，修改 DemoController.java

import io.github.jihch.pojo.People;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;

@RestController
public class DemoController {

    @RequestMapping("/demo")
    public String demo() {
        return "demo1";
    }
}

启动，再修改 DemoController.java

import io.github.jihch.pojo.People;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;

@RestController
public class DemoController {

    @RequestMapping("/demo")
    public String demo() {
        return "demo2";
    }
}

因为这次使用了应用 Ribbon 的 RestTemplate 对 Application Service 提供的接口进行调用，浏览器重复多次访问 Application Client 的 “/demo”URL，demo1 和 demo2 将交替出现，