引入restTemplate

@EnableDiscoveryClient
@EnableFeignClients
@SpringBootApplication
public class OrderApplication {

    @Bean
    @LoadBalanced
    //添加注解@SentinelRestTemplate
    @SentinelRestTemplate
    public RestTemplate getRestTemplate() {
        return new RestTemplate();
    }
    public static void main(String[] args) {
        SpringApplication.run(OrderApplication.class);
    }
}

控制器，通过RestTemplate 实现http请求

@RestController
public class RestTemplateController {

    @Autowired
    private RestTemplate restTemplate;

    @GetMapping("/order/{id}")
    public String getUser(@PathVariable Integer id){
      String result =  restTemplate.getForObject("http://msb-user:10001/user/" + id, String.class);
        return result;
    }
}

服务提供者

@RestController
public class UserController {

    @GetMapping("/user/{userId}")
    public String getUserName(@PathVariable Integer userId){
        return "善缘老师";
    }
}

添加流控

注意选对流控请求

正常请求

频繁请求

统一异常处理

注解添加属性

   @Bean
    @LoadBalanced
    @SentinelRestTemplate(blockHandler = "handleException",
            blockHandlerClass= GlobalException.class
            ,fallback = "fallback",
            fallbackClass = GlobalException.class)
    public RestTemplate getRestTemplate() {
        return new RestTemplate();
    }
    public static void main(String[] args) {
        SpringApplication.run(OrderApplication.class);
    }

异常类注意对象的引用，引用错误则启动报错

import com.alibaba.cloud.sentinel.rest.SentinelClientHttpResponse;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.msb.order.util.Result;
import org.springframework.http.HttpRequest;

import org.springframework.http.client.ClientHttpRequestExecution;

public class GlobalException {

    public static SentinelClientHttpResponse handleException(HttpRequest request,
                                                             byte[] body, ClientHttpRequestExecution execution, BlockException ex) {
        Result r = Result.error(-1, "===被限流啦===");
        System.out.println("近日来零三零三零是否");
        try {
            return new SentinelClientHttpResponse(new ObjectMapper().writeValueAsString(r));
        } catch (JsonProcessingException e) {
            e.printStackTrace();
        }
        return null;
    }

    public static SentinelClientHttpResponse fallback(HttpRequest request,
                                                      byte[] body, ClientHttpRequestExecution execution, BlockException ex) {
        Result r = Result.error(-2, "===被异常降级啦===");
        System.out.println("近日来零三零三零是否2");
        try {
            return new SentinelClientHttpResponse(new ObjectMapper().writeValueAsString(r));
        } catch (JsonProcessingException e) {
            e.printStackTrace();
        }
        return null;
    }
}

异常请求