Two ways to pass feign exceptions: fallbackfactory and global processing Get server-side custom exceptions

Generally, when we use feign to call the interface, if the service provider has an exception, the caller will generally display

feign.FeignException$BadRequest: status 400 reading

Regardless of the downtime of the server, the corresponding information will be thrown when there is an exception, but the caller cannot obtain it in general.
Through testing, we found that if you print the log, you can see itThe log thrown by the service provider, but the caller cannot capture it, will only report a 400 exception.
So if we want to pass exceptions, we can have two ways, but most of them need to be adjusted by the caller.

First, fallbackFactory

FallbackFactory is similar to the standard fuse downgrade, which can bring all the exception information, but we need to convert the exception, and the regular exception still cannot get the body part.
So here we use FeignException to force the transfer, and the problem is solved.
Look, we can get the custom error thrown by the server.
At this time, you can convert the json to bean.

Reference:
Server and Client Common

@FeignClient(value = "sq-service", path = "/service",url = "http://localhost:9980", fallbackFactory = TestFactory.class)public interface TestApi {@PostMapping("/test")String test();}@Componentpublic class TestFactory implements FallbackFactory {@Overridepublic TestApi create(final Throwable throwable) {FeignException ex = (FeignException) throwable;JSONObject jsonObject = JSONObject.parseObject(ex.contentUTF8());return new TestApi() {@Overridepublic String test() {return jsonObject.getString("message");}};}}

Attention!If the client wants to fuse and downgrade, it must be configured in the yaml file:

Client:

feign:hystrix:enabled: true

Otherwise cannot enter fallbackFactory

Second, once and for all, global configuration

I solve it directly with a config file!
Compared with fallbackFactory, there is no need for common code, no need to fuse and downgrade, and the server does not need to make any changes, only the client configuration is required.If you can't change the server, try not to move, otherwise, you really want to diss.

Client

@Configurationpublic class FeignErrorDecoder implements ErrorDecoder {@Overridepublic Exception decode(final String methodKey, final Response response) {try {String message = Util.toString(response.body().asReader());try {JSONObject jsonObject = JSONObject.parseObject(message);// Wrap it into your own custom exception, here it is recommended to change it according to your own codereturn new MyException(jsonObject.getString("message"), jsonObject.getInteger("code"));} catch (JSONException e) {e.printStackTrace();}} catch (IOException ignored) {}return decode(methodKey, response);}}

As you can see, this method can directly feedback to the caller,In other words, front-end calls can be directly displayed on the web page.It can be said that it is very direct to tell you that it is abnormal.

Feign's exception delivery is as simple as that. Generally speaking, projects have their own custom exception global classes for reference only.
Global processing is strongly recommended!!!

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