Openfeign service interface call

summary

Feign It's a statement WebService client . Use Feign Can make writing WebService The client is simpler .

It's used by defining a service interface and then adding annotations to it .Feign It also supports pluggable encoders and decoders .Spring Cloud Yes Feign It was packaged , To support Spring MVC Standard notes and HttpMessageConverters.Feign It can be done with Eureka and Ribbon Combined to support load balancing .

One sentence summary ：Feign It's a declarative one Web Service client , Let's write web Service clients become very easy , Just create an interface and annotate it .

Feign Designed to make writing Java Http The client becomes easier .
Use Ribbon+RestTemplate when , utilize RestTemplate Yes Http Encapsulation processing of requests , It forms a set of template calling methods , But in actual development , Because there may be more than one call to a service , Often an interface is called in multiple places , So we usually encapsulate some client classes for each microservice to package the calls of these dependent services . therefore ,Feign On this basis, we make further encapsulation , It helps us define and implement the definition of dependent service interface . stay Feign Under the realization of , We just need to create an interface and use annotations to configure it , You can complete the interface binding to the service provider , Simplified use spring cloud ribbon when , Development volume of auto encapsulation service calling client .

Feign Integrated Ribbon, adopt Feign Just define the service binding interface and use declarative methods , Elegant and simple implementation of service invocation .

Feign Has been OpenFeign replace .

Feign	OpenFeign
Feign yes spring cloud One of the lightweight components RESTful Of HTTP Service client Feign Built in Ribbon, It is used for client load balancing , To call the service in the service registry .Feign Is used in the following way ： Use Feign The annotation defines the interface , Call this interface , You can call the service in the service registry .	OpenFeign yes spring cloud stay Feign Based on the support of SpringMVC Annotations , Such as @RequestMapping wait .OpenFeign Of @FeignClient Can be parsed SpringMVC Of @RequestMapping Interface under annotation , And through the way of dynamic proxy to produce the implementation class , Load balancing in the implementation class and calling other services .

Use steps

newly build cloud-consumer-feign-order80 modular .

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>cloud2022</artifactId>
        <groupId>com.qrxqrx.springcloud</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>cloud-consumer-feign-order80</artifactId>

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
        <dependency>
            <groupId>com.qrxqrx.springcloud</groupId>
            <artifactId>cloud-api-commons</artifactId>
            <version>${project.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
    </dependencies>

</project>

application.yml

server:
  port: 80

eureka:
  client:
    register-with-eureka: false
    service-url:
      defaultZone: http://eureka7001.com:7001/eureka/,http://eureka7002.com:7002/eureka/

OrderFeignMain80

package com.qrxqrx.springcloud;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.openfeign.EnableFeignClients;

@SpringBootApplication
@EnableFeignClients
public class OrderFeignMain80 {
    

    public static void main(String[] args) {
    
        SpringApplication.run(OrderFeignMain80.class,args);
    }

}

PaymentFeignService

package com.qrxqrx.springcloud.service;

import com.qrxqrx.springcloud.entities.CommonResult;
import com.qrxqrx.springcloud.entities.Payment;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;

@Component
@FeignClient(value = "CLOUD-PAYMENT-SERVICE")
public interface PaymentFeignService {
    

    @GetMapping(value = "/payment/get/{id}")
    public CommonResult<Payment> getPaymentById(@PathVariable("id") Long id);

}

OrderFeignController

package com.qrxqrx.springcloud.controller;

import com.qrxqrx.springcloud.entities.CommonResult;
import com.qrxqrx.springcloud.entities.Payment;
import com.qrxqrx.springcloud.service.PaymentFeignService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;

import javax.annotation.Resource;

@RestController
@Slf4j
public class OrderFeignController {
    

    @Resource
    private PaymentFeignService paymentFeignService;

    @GetMapping(value = "/consumer/payment/get/{id}")
    public CommonResult<Payment> getPaymenyById(@PathVariable("id") Long id) {
    
        return paymentFeignService.getPaymentById(id);
    }

}

OpenFeign Timeout control

Default feign The client just waits 1 second , But the server-side processing needs more than 1 second , Lead to feign The client doesn't want to wait , Direct return error . To avoid such a situation , Sometimes you need to set up feign Timeout control of client .

server:
  port: 80

eureka:
  client:
    register-with-eureka: false
    service-url:
      defaultZone: http://eureka7001.com:7001/eureka/,http://eureka7002.com:7002/eureka/

#  Set up feign Client timeout 
ribbon:
  #  It refers to the time taken to read the available resources from the server after the connection is established 
  ReadTimeout: 5000
  #  The time taken to establish a connection , It is suitable for normal network conditions , The time taken to connect the two ends 
  ConnectTimeout: 5000

OpenFeign Log printing function

Feign Provides log printing function , The log level can be adjusted through configuration , Thus understand Feign in Http Details of the request . Yes Feign Monitor and output the interface call .

The level of logging ：

• NONE： default , Don't show any logs .
• BASIC： Only the request method is recorded 、URL、 Response status code and execution time .
• HEADERS： except BASIC In addition to the information defined in , And the request and response headers .
• FULL： except HEADERS In addition to the information defined in , And the body and metadata of the request and response .

Add configuration class ：
FeignConfig

package com.qrxqrx.springcloud.config;

import feign.Logger;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;



@Configuration
public class FeignConfig {
    

    @Bean
    Logger.Level feignLoggerLevel() {
    
        return Logger.Level.FULL;
    }

}

Modify the configuration ：
application.yml

server:
  port: 80

eureka:
  client:
    register-with-eureka: false
    service-url:
      defaultZone: http://eureka7001.com:7001/eureka/,http://eureka7002.com:7002/eureka/

#  Set up feign Client timeout 
ribbon:
  #  It refers to the time taken to read the available resources from the server after the connection is established 
  ReadTimeout: 5000
  #  The time taken to establish a connection , It is suitable for normal network conditions , The time taken to connect the two ends 
  ConnectTimeout: 5000


logging:
  level:
    # feign At what level does the log monitor which interface 
    com.qrxqrx.springcloud.service.PaymentFeignService: debug