SpringCloud-Feign接口转换服务

Feign是通过提供面向接口操作的方式来替代RestTemplate API的Rest操作。

使用Feign

Feign这种技术应用在服务消费端

1. 修改pom.xml配置文件，加入Feign的依赖包

    org.springframework.cloud
    spring-cloud-starter-feign

2. 由于Fegin是将Rest的操作转换成接口的形式，所以我们需要新建一个接口，并在接口上声明@FeignClient注解

@FeignClient(value = "DEPT-PROVIDER",configuration = FeignClientConfig.class)
public interface DeptClientService {
    @RequestMapping(method= RequestMethod.GET,value="/dept/get/{id}")
    public Dept get(@PathVariable("id") long id) ;
    @RequestMapping(method=RequestMethod.GET,value="/dept/list")
    public List list() ;
    @RequestMapping(method=RequestMethod.POST,value="/dept/add")
    public boolean add(Dept dept) ;
}

@Configuration
public class FeignClientConfig {
    @Bean
    public Logger.Level getFeignLoggerLevel() {
        return feign.Logger.Level.FULL ;
    }
    @Bean
    public BasicAuthRequestInterceptor getBasicAuthRequestInterceptor() {
        return new BasicAuthRequestInterceptor("admin", "admin");
    }
}

其中configuration = FeignClientConfig.class不是必须的，将configuration属性去除仍然能work。

3. 将之前的Rest操作的API，替换成面向DeptClientService接口的形式

@RestController
@RequestMapping("/consumer/dept")
public class ConsumerDeptController {

    @Autowired
    private DeptClientService deptClientService;

    @RequestMapping(value = "/get")
    public Dept get(long id) {
        return this.deptClientService.get(id);
    }

    @RequestMapping("/list")
    public List list(){
        return this.deptClientService.list();
    }

    @RequestMapping("/add")
    public boolean add(Dept dept){
        return this.add(dept);
    }
/*
    public static final String DEPT_GET_URL = "http://DEPT-PROVIDER/dept/get/";
    public static final String DEPT_LIST_URL = "http://DEPT-PROVIDER/dept/list/";
    public static final String DEPT_ADD_URL = "http://DEPT-PROVIDER/dept/add";

    @Autowired
    private RestTemplate restTemplate;
    @Autowired
    private HttpHeaders httpHeaders;
    @Autowired
    private LoadBalancerClient loadBalancerClient;

    @RequestMapping(value = "/get")
    public Dept get(long id) {
        ServiceInstance serviceInstance = this.loadBalancerClient.choose("DEPT-PROVIDER") ;
        System.out.println(
                "【*** ServiceInstance ***】host = " + serviceInstance.getHost()
                        + "、port = " + serviceInstance.getPort()
                        + "、serviceId = " + serviceInstance.getServiceId());
        //Dept dept = restTemplate.getForObject(DEPT_GET_URL + id, Dept.class);
        Dept dept = restTemplate.exchange(DEPT_GET_URL+id, HttpMethod.GET,new HttpEntity