spring cloud之Feign的使用

原始的調用客戶端的方式是通過註入restTemplate的方式

restTemplate.getForObject("http://CLIENT/hello", String.class)

通過feign的方式

配置消費者項目cloud-consume

pom.xml

依賴jar

<dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>

application.yml

添加啟動feign 可實現錯誤回調

feign:
  hystrix:
    enabled: true

啟動應用類

ClondConsumeApplication.java

添加註解@EnableFeignClients

HelloService.java介面

package com.tp.soft.cloudconsume.service;

import com.tp.soft.cloudconsume.service.impl.HelloServiceFallback;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;

@FeignClient(value = "CLIENT", fallback = HelloServiceFallback.class)
public interface HelloService {
    @GetMapping("/hello")
    String hello();
}

其中CLIENT則為註冊中心被調用的應用名,/hello完全和客戶端業務介面一樣,fallback則為錯誤回調的方法,同時可以防止應用雪崩效應.

HelloServiceFallback.java介面

package com.tp.soft.cloudconsume.service.impl;

import com.tp.soft.cloudconsume.service.HelloService;
import org.springframework.stereotype.Component;

@Component
public class HelloServiceFallback implements HelloService {
    @Override
    public String hello() {

        return "request error";
    }
}

HelloController.java

package com.tp.soft.cloudconsume.controller;

import com.tp.soft.cloudconsume.service.HelloService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

import javax.annotation.Resource;

@RestController
public class HelloController {

//    @Autowired
//    RestTemplate restTemplate;

    @Resource
    private HelloService helloService;

    @GetMapping("hi")
    public String hi(){
        //return restTemplate.getForObject("http://CLIENT/hello", String.class);
        return helloService.hello();
    }
}

和原來在controller調用介面一模一樣的去調用就可以了

最後的效果: