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This article mainly introduces the relevant knowledge of how to use OpenFeign, the content is detailed and easy to understand, the operation is simple and fast, and has a certain reference value. I believe you will gain something after reading this article on how to use OpenFeign. Let's take a look at it.

Introduction to the basic use of OpenFeign in OpenFeign

OpenFeign is a declarative http client, which makes it very easy to write a web service client. You only need to create an interface and add comments on the interface. The predecessor of OpenFeign is Feign, which has been stopped. OpenFeign is SpringCloud that supports Spring MVC annotations on the basis of Feign, and generates implementation classes to do load balancing and call other services through dynamic proxy.

Ribbon+RestTemplate is too cumbersome, and development can be simplified through OpenFeign

Basic use

Take the commodity invoked by user service as an example

User Service configuration OpenFeign

Import dependency

Org.springframework.cloud spring-cloud-starter-openfeign

Add comments to the startup class

Write the called interface in the merchandise service (no interface test)

Use Feign to write service invocation directly in user service

Create a normal Java interface

Declare the client with the current interface as Feign through annotations

The method of writing service invocation in Feign interface

Use the Feign interface in the Controller of user service

Start all services two merchandise services one user service registry access user service observation service invocation

You can see the effect of load balancing by accessing the Controller of the user service.

Process flow

On the processing of passing parameters

Parameters are passed as json requests, which are actually RestFul requests.

/ {} stitching parameters

Example of called API [goods and services]

Feign API example [user Service]

? Stitching parameters correspond to common request types Get requests

Example of called API [goods and services]

Feign API example [user Service]

The parameters passed by the request body correspond to common request Post requests

Example of called API [goods and services]

Feign API example [user Service]

Open the log

Unlike RestTemplate, Feign encapsulates the details of the request more thoroughly, whether it is the request or the parameters of the request or the status of the response. To see the details of the request, you need to go to the log of Feign.

Configuration of Feign logs

1. Configuration class @ Bean

[@ Bean] (https://my.oschina.net/bean)public Logger.Level feignConfig () {return Logger.Level.FULL;})

two。 Open the log of the package of the Feign interface in the configuration file

If you restart the project with the above configuration and use the Feign service call again, you will see the following log:

Feign parameter tuning 1. Replace OKHttp

By default, when spring cloud feign makes calls between child services, the http component uses jdk's HttpURLConnection and does not use thread pools.

There are two optional thread pools: HttpClient and OKHttp, OKHttp is recommended, the request encapsulation is very easy to use, and the performance is very ok.

Add dependency

Com.squareup.okhttp3 okhttp

Modify the configuration file

Feign: okhttp: enabled: true httpclient: enabled: false max-connections: 1000 max-connections-per-route: 100

Max-connections: maximum connections

Max-connections-per-route: number of connections per url

two。 Enable Feign request response compression

Enabling compression can effectively save network resources, but it will increase the pressure on CPU. It is recommended to appropriately increase the size of the minimum compressed document.

# # enable Feign request response compression feign.compression.request.enabled=truefeign.compression.response.enabled=true## configuration compressed document type and minimum compressed document size feign.compression.request.mime-types=text/xml,application/xml,application/jsonfeign.compression.request.min-request-size=2048 on "how to use OpenFeign" this article is introduced here, thank you for reading! I believe you all have a certain understanding of the knowledge of "how to use OpenFeign". If you want to learn more, you are welcome to follow the industry information channel.

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