标签Feign

1. 增加依赖

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

1. 在启动主类增加注解

@EnableFeignClients

1. 定义feign调用商品微服务的接口

访问PRODUCT服务下的接口
@FeignClient(name = "PRODUCT")
public interface ProductClient {

    /**
     * 从商品微服务中获取一个测试信息
     * @return
     */
    @GetMapping("/msg")
    String productMsg();

    /**
     * 根据一组商品ID获取商品列表
     * @param productIdList
     * @return
     */
    @PostMapping("/listForOrder")
    List<ProductInfoOutput> listForOrder(@RequestBody List<String> productIdList);

    /**
     * 扣库存
     * @param decreaseStockInputList
     */
    @PostMapping("/decreaseStock")
    void decreaseStock(@RequestBody List<DecreaseStockInput> decreaseStockInputList);
}

1. 调用feign接口

@Api(tags="RestTemplate/feign调用微服务API")
@RestController
@Slf4j
public class ClientController {
    /*第二种方式*/
   /* @Autowired
    private LoadBalancerClient loadBalancerClient;*/

    /* 第三种方式
     @Autowired
    private RestTemplate restTemplate;*/

    /*第四种方式feign*/
    @Autowired
    private ProductClient productClient;

    @ApiOperation("获取一个测试信息")
    @GetMapping("/msg")
    public String getProductMsg(){
        //第一种方式 直接使用RestTemplate,URL固定
        //RestTemplate restTemplate = new RestTemplate();
        //String response = restTemplate.getForObject("http://localhost:8080/productserver/msg",String.class);

        //第二种方式 直接使用RestTemplate,URL利用LoadBalancerClient获取
        /*RestTemplate restTemplate = new RestTemplate();
        ServiceInstance serviceInstance = loadBalancerClient.choose("PRODUCT");
        String url = String.format("http://%s:%s/msg",serviceInstance.getHost(),serviceInstance.getPort());
        String response = restTemplate.getForObject(url,String.class);*/

        //第三种,将 RestTemplate 作为一个Bean 配制到项目,使用注解@LoadBalanced,在restTemplate直接使用应用名字
        //String response = restTemplate.getForObject("http://PRODUCT/msg",String.class);
        //4.feign
        String response = productClient.productMsg();
        log.info("response={}",response);
        return response;
    }
    }
    第三种方式使用注解@LoadBalanced的配制文件
    @Component
    public class RestTemplateConfig {
     @Bean
    @LoadBalanced
    public RestTemplate restTemplate(){
        return new RestTemplate();
    }
    or
    @Bean
    @LoadBalanced
    public RestTemplate restTemplate(){
        //return new RestTemplate();
        return new RestTemplateBuilder().basicAuthentication("oauth", "123").build();
    }
    }

HttpHeaders header = new HttpHeaders();
header.setContentType(MediaType.APPLICATION_FORM_URLENCODED);
MultiValueMap<String, String> map= new LinkedMultiValueMap<>();
map.add(“grant_type”, “password”);
map.add(“client_id”, “oauth”);
HttpEntity<MultiValueMap<String, String>> request = new HttpEntity<>(map, header);
MyToken myToken = restTemplate.postForObject(“http://192.168.88.108:30002/oauth/token”,request,MyToken.class);

    // build http headers
    HttpHeaders headers = new HttpHeaders();
    headers.add("Authorization","bearer "+myToken.getAccess_token());
    ResponseEntity<ClientUser[]> responseEntity = restTemplate.exchange(RBAC_SERVER+POST_ALL_USER, HttpMethod.GET,new HttpEntity<String>(headers),ClientUser[].class);