Spring Cloud Alibaba-Feign (14)

Introduction to the

Feign makes writing Java HTTP Clients Easier Official document

Integration of Feign

• And rely on

<! - the version defined by the parent project - > < the dependency > < groupId > org. Springframework. Cloud < / groupId > <artifactId>spring-cloud-starter-openfeign</artifactId> </dependency>Copy the code

• Write notes

@EnableFeignClients
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• Write the configuration

There is noCopy the code

use

package com.virgo.user.feignclient; import com.virgo.entity.TblCar; import com.virgo.user.configuration.GlobalFeignConfiguration; import com.virgo.user.feignclient.fallbackFactory.LockCenterFeignClientFallbackFactory; import org.springframework.cloud.openfeign.FeignClient; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.PathVariable; /** * @author zhaozha * @date 2019/10/11 12:52 PM */ @feignClient (name ="lock-center". configuration = GlobalFeignConfiguration.class,fallbackFactory = LockCenterFeignClientFallbackFactory.class) public Interface LockCenterFeignClient {// Automatic build http://lock-center/lock/test/{id}
    @GetMapping("/lock/test/{id}")
    TblCar findById(@PathVariable(value="id") Long id); } // Controller ... private final LockCenterFeignClient lockCenterFeignClient; . TblCar tblCar = lockCenterFeignClient.findById(4000002L); .Copy the code

composition

The level of logging

The log configuration

• Fine-grained code

  • yml

  Feign log level set (code) logging: level: com. Virgo. User. Feignclient. LockCenterFeignClient: debugCopy the code

  • code

  package com.virgo.user.feignclient; import com.virgo.entity.TblCar; import com.virgo.user.configuration.GlobalFeignConfiguration; import com.virgo.user.feignclient.fallbackFactory.LockCenterFeignClientFallbackFactory; import org.springframework.cloud.openfeign.FeignClient; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.PathVariable; /** * @author zhaozha * @date 2019/10/11 12:52 PM */ @feignClient (name ="lock-center". configuration = GlobalFeignConfiguration.class,fallbackFactory = LockCenterFeignClientFallbackFactory.class) public interface LockCenterFeignClient { @GetMapping("/lock/test/{id}")
      TblCar findById(@PathVariable(value="id") Long id);
  }
  
  GlobalFeignConfiguration.class
  package com.virgo.user.configuration;
  
  import feign.Logger;
  import org.springframework.context.annotation.Bean;
  
  /**
   * @author zhaozha
   * @date 2019/10/11 下午1:18
   */
  public class GlobalFeignConfiguration {
      @Bean
      public Logger.Level level(){// have Feign print the details of all requestsreturnLogger.Level.FULL; }}Copy the code

• Fine-grained configuration

feign:
  client:
    config:
      lock-center:
        loggerLevel: FULL
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• Global code

@EnableFeignClients(defaultConfiguration = GlobalFeignConfiguration.class)
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• Global configuration

feign:
  client:
    config:
      default:
        loggerLevel: FULL
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Configuration items

code

configuration

feign:
  client:
    config:
      # global
      default:
        # log level
        loggerLevel:
        Connection timeout
        connectTimeout:
        Read timeout
        readTimeout:
        Error decoder
        errorDecoder:
        Retry policy
        retryer:
        # interceptor
        requestInterceptors:
        # 404 Error code decoding
        decode404:
        # encoder
        encoder:
        # decoder
        decoder:
        # contract
        contract:
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inheritance

todo

multi-parameter

@GetMapping("/lock/car/{carId}/user/{userId}")
TblCar findById(@PathVariable(value="carId") Long carId,@PathVariable(value="userId") Long userId);
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Out of the ribbon

@FeignClient(name="",url="")
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feign & restTemplate

• Performance: the restTemplate
• Readability: Feign

To optimize the

feign:
  httpclient:
    # let feign use Apache HttpClient for requests. Instead of the default URlConnection
    enabled: true
    # feign maximum number of connections
    max-connections: 200
    # feign Specifies the maximum number of connections for a single path
    max-connections-per-route: 50
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fallback & fallbackFactory

• fallback

// 1 Annotation @feignClient (.... , fallback = XXX. Class) / / 2 code package com. Virgo. User. Feignclient. Fallback; import com.virgo.entity.TblCar; import com.virgo.user.feignclient.LockCenterFeignClient; import org.springframework.stereotype.Component; / * * * @ author zhaozha * @ date "* / 2019/10/16 afternoon @ Component public class LockCenterFeignClientFallback implements LockCenterFeignClient { @Override public TblCar findById(Long id,Long userId) {return TblCar.builder().level(1).build();
    }

    @Override
    public TblCar testPost(String params) {
        returnnull; }}Copy the code

• FallbackFactory (stronger than Fallback, can print exceptions)

// 1 Annotation @feignClient (.... , fallbackFactory = XXX. Class) / / 2 code package com. Virgo. User. Feignclient. FallbackFactory; import com.virgo.entity.TblCar; import com.virgo.user.feignclient.LockCenterFeignClient; import feign.hystrix.FallbackFactory; import lombok.extern.slf4j.Slf4j; import org.springframework.stereotype.Component; / * * * @ author zhaozha 4:02 * / * @ date 2019/10/16 afternoon @ Component @ Slf4j public class LockCenterFeignClientFallbackFactory implements FallbackFactory<LockCenterFeignClient> { @Override public LockCenterFeignClient create(Throwable throwable) {return new LockCenterFeignClient() {
            @Override
            public TblCar findById(Long id,Long userId) {
                log.info("Current limiting/degradation",throwable);
                return TblCar.builder().level(1).build();
            }

            @Override
            public TblCar testPost(String params) {
                returnnull; }}; }}Copy the code