feign client远程调用时，如果遇到返回的http status不是200的情况，则会抛出异常feign.FeignException。但是这种异常不方便处理，所以最好还是根据错误信息抛出自定义异常

抛出自定义异常

• 自定义异常

public class HwException extends RuntimeException {
    public HwException(String message) {
        super(message);
    }
}

• 定义ErrorDecoder

public class HwNetApiErrorDecoder implements ErrorDecoder {
    final ObjectMapper mapper;

    public HwNetApiErrorDecoder(ObjectMapper mapper) {
        this.mapper = mapper;
    }

    @Override
    public Exception decode(String methodKey, Response response) {
        if (HttpStatus.OK.value() == response.status()) {
            //这里不应该出现，因为只有不是200的返回结果，才是错误
            FeignException exception = errorStatus(methodKey, response);
            throw new RuntimeException(exception);
        }
        try {
            HwNetResult<?> netRet = mapper.readValue(response.body().asInputStream(), HwNetResult.class);
            if (netRet.isSuccess()) {
                throw new RuntimeException("return values is success but http status is not 200");
            }
            throw new HwException(netRet.getErrorCode());
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
}

• Feign自定义配置:

public class WxFeignConfiguration {
    @Bean
    public HwNetApiErrorDecoder hwNetApiErrorDecoder(ObjectMapper mapper) {
        return new HwNetApiErrorDecoder(mapper);
    }
}

效果

• 当http请求返回400错误时，并且error_code="one_IE"时，则会抛出异常HwException: one_IE

java.lang.IllegalStateException: Failed to execute ApplicationRunner
    at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:762)
    at org.springframework.boot.SpringApplication.callRunners(SpringApplication.java:749)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:314)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1303)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1292)
    at com.wx.demo.server.WxkjDemoServerApplication.main(WxkjDemoServerApplication.java:34)
Caused by: com.wx.hardware.huawei.api.service.HwException: one_IE
    at com.wx.hardware.huawei.api.service.HwNetApiErrorDecoder.decode(HwNetApiErrorDecoder.java:34)
    at feign.ResponseHandler.decodeError(ResponseHandler.java:136)
    at feign.ResponseHandler.handleResponse(ResponseHandler.java:70)
    at feign.SynchronousMethodHandler.executeAndDecode(SynchronousMethodHandler.java:114)
    at feign.SynchronousMethodHandler.invoke(SynchronousMethodHandler.java:70)
    at feign.ReflectiveFeign$FeignInvocationHandler.invoke(ReflectiveFeign.java:96)
    at com.sun.proxy.$Proxy77.deviceInfo(Unknown Source)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)