Java之Springcloud Feign组件详解

@SpringBootApplication
@MapperScan("com.csqf.mapper")
@Import({
        swagger2Config.class,
        ControllerExceptionAdvice.class,
})
@EnableFeignClients
public class SpringCloud_share_6002 {
    public static void main(String[] args) {
        SpringApplication.run(sprinGCloud_share_6002.class,args);
    }

    @Bean
    @LoadBalanced
    public RestTemplate restTemplate(){
        return new RestTemplate();
    }
}

@Service
@FeignClient("user-6001")
public interface UserFeignService {

    @GetMapping("/api/user/{id}")
    public R getUserNameById(@PathVariable("id") Integer id);
}

@RestController
@RequestMapping("/api/share")
public class ShareContoller {
    @Autowired
    private ShareServiceImpl shareService;
//    @Autowired
//    private RestTemplate restTemplate;
//    @Autowired
//    private DiscoveryClient discoveryClient;
    @Autowired
    private UserFeignService userFeignService;

    @GetMapping("/{id}")
    public R getShareById(@PathVariable("id") Integer id) {
        Share share = shareService.getShareById(id);
        R r = userFeignService.getUserNameById(share.getUserId());
        String s = r.getData().toString();
        ShareDto shareDto = new ShareDto();
        BeanUtils.copyProperties(share,shareDto);
        shareDto.setUserName(s);
        return new R(ResponseEnum.SUCCESS,shareDto);
    }
}

	1：如果所有的重试完成 还是失败 要抛出  feign.RetryableException 异常																																																																																																					
	2： 重试 会产生接口的幂等性问题：																																																																																																	
			1：查询的接口 天生是幂等的																																																					
			2： 增删改的处理	非幂等的																																																																																																									

    @ExceptionHandler(RetryableException.class)
    @ResponseBody
    public R doException(RetryableException ex){
        ex.printStackTrace();
        //  System.out.println("抛出未知异常");
        return new R(ResponseEnum.FEIGN_RETRY,null);
    }