服务调用之Feign显示fallback异常原因

Feign显示fallback异常原因

我在最一开始使用Feign的时候，是使用FallBack类去实现的FeignClient接口，就像这样

@FeignClient(name = "SPRINGCLOUD2-PROVIDER",contextId = "DeptClient",
        fallback = DeptClient.DeptClientFallBack.class)
public interface DeptClient {

    @GetMapping(value = "/dept/get/{id}")
    CommonResult<Dept> get(@PathVariable("id") long id);

    @GetMapping("/timeout")
    String timeout();
    
    @Component
    class DeptClientFallBack implements DeptClient{

        @Override
        public CommonResult<Dept> get(long id) {
            return null;
        }

        @Override
        public String timeout() {
            return null;
        }
    }
}

但是这样的话，我发现没有办法查看是因为什么原因造成的fallback呢，这种方法肯定是不行的

然后发现@FeignClient注解中有一个属性是fallbackFactory，看着这个是有一个Throwable参数的，拿来试一试

T create(Throwable cause);

说干就干

@FeignClient(name = "SPRINGCLOUD2-PROVIDER",contextId = "DeptClient",
        fallbackFactory = DeptClientFallBackFactory.class)
public interface DeptClient {

    @GetMapping(value = "/dept/get/{id}")
    CommonResult<Dept> get(@PathVariable("id") long id);

    @GetMapping("/timeout")
    String timeout();
}

@Component
public class DeptClientFallBackFactory implements FallbackFactory<DeptClient> {

    @Override
    public DeptClient create(Throwable throwable) {
        return new DeptClient() {
            @Override
            public CommonResult<Dept> get(long id) {
                System.out.println("fallback 原因:"+throwable.getMessage());
                CommonResult<Dept> result = new CommonResult<>();
                result.isOk();
                return result;
            }

            @Override
            public String timeout() {
                return null;
            }
        };
    }
}

可以拿到异常信息了

参考文献

• Feign显示fallback异常原因

• https://www.jianshu.com/p/d992c3647cc4