筆記:spring boot 集成eureka、feign

spring boot 改造微服務 可以使用 spring cloud 組件快速實現

Spring Cloud集成相關優質項目推薦（圖片源自springcloud中文網）

首先來集成 eureka 服務註冊與發現

PS：項目是gradle 構建的

新建eurka服務端項目 啓動項加入@EnableEurekaServer

@SpringBootApplication
@EnableEurekaServer
public class EurekaApplication {

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

}

配置如下

compile group: 'org.springframework.cloud', name: 'spring-cloud-starter-netflix-eureka-server', version: '2.2.3.RELEASE'

server:
  port: 8761


eureka:
  client:
    service-url:
      defaultZone: http://user:xxxx@localhost:8762/eureka
    register-with-eureka: false
  server:
    enable-self-preservation: false # 設爲false，關閉自我保護
    eviction-interval-timer-in-ms: 5000 # 清理間隔


spring:
  application:
    name: eureka-1
  security:
    user:
      name: user
      password: xxxx

安全起見推薦使用webSecurity 簡單的加密 ，高可用就啓動多個eurekaServer

然後就是eureka客戶端 啓動類加@EnableDiscoveryClient註解 然後配置文件加入(注意要寫spring.application.name 服務的名字)

compile group: 'org.springframework.cloud', name: 'spring-cloud-starter-netflix-eureka-client', version: '2.2.3.RELEASE'
compile group: 'org.springframework.cloud', name: 'spring-cloud-starter-openfeign', version: '2.2.3.RELEASE'

eureka:
  client:
    service-url:
      defaultZone: http://localhost:8761/eureka/,http://localhost:8762/eureka/

然後啓動 會提示

修改下配置 JAR manifest即可

接着啓動客戶端 再去eureka註冊中心查看服務註冊情況

至此 eureka的服務註冊就配置完成了 然後開始配置feign的服務間調用

使用@EnableFeignClients註解 開啓feign的客戶端

然後我喜歡單獨建個package 寫調用另外一個服務的客戶端

@FeignClient(name = "park-info", fallback = ParkInfoClient.ProductClientFallback.class)
public interface ParkInfoClient {

    @PostMapping(value = "/admin/internalCar/isInternalCar", headers = {"version=2.0", "Authorization=xxxx"})
    ResultVO isInternalCar(@RequestBody InternalCarRequest params);

    @PostMapping(value = "/admin/limitCar/isLimitCar", headers = {"version=2.0", "Authorization=xxx"})
    ResultVO isLimitCar(@RequestBody InternalCarRequest params);

    @Component
    class ProductClientFallback implements ParkInfoClient {

        @Override
        public ResultVO isInternalCar(InternalCarRequest params) {
            return ResultVoUtil.failed("請求失敗");
        }

        @Override
        public ResultVO isLimitCar(InternalCarRequest params) {
            return ResultVoUtil.failed("請求失敗");
        }
    }
}

然後其他地方直接注入這個Client，調用Client的方法即可調用其他服務， 有複雜對象 新建DTO作爲傳輸對象

配置feign的連接超時、響應超時設置

feign:
  client:
    config:
      default:
        connectTimeout: 3000
        readTimeout: 3000

feign調用也實現了，多個相同的服務負載均衡默認是輪詢方式調用

下面是feign的json轉換使用fastjson

package com.easyparking.cloudplatform.common.webmvc.config;

import com.alibaba.fastjson.serializer.SerializerFeature;
import com.alibaba.fastjson.support.config.FastJsonConfig;
import com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter;
import org.springframework.beans.factory.ObjectFactory;
import org.springframework.boot.autoconfigure.http.HttpMessageConverters;
import org.springframework.cloud.openfeign.support.ResponseEntityDecoder;
import org.springframework.cloud.openfeign.support.SpringDecoder;
import org.springframework.cloud.openfeign.support.SpringEncoder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.MediaType;
import org.springframework.http.converter.HttpMessageConverter;

import java.util.ArrayList;
import java.util.List;

/**
 * @author cctv
 * @date 2020/7/3 14:17
 */
@Configuration
public class FeignConfig {

    @Bean
    public ResponseEntityDecoder feignDecoder() {
        HttpMessageConverter fastJsonConverter = createFastJsonConverter();
        ObjectFactory<HttpMessageConverters> objectFactory = () -> new HttpMessageConverters(fastJsonConverter);
        return new ResponseEntityDecoder(new SpringDecoder(objectFactory));
    }

    @Bean
    public SpringEncoder feignEncoder(){
        HttpMessageConverter fastJsonConverter = createFastJsonConverter();
        ObjectFactory<HttpMessageConverters> objectFactory = () -> new HttpMessageConverters(fastJsonConverter);
        return new SpringEncoder(objectFactory);
    }

    private HttpMessageConverter createFastJsonConverter() {

        //創建fastJson消息轉換器
        FastJsonHttpMessageConverter fastConverter = new FastJsonHttpMessageConverter();

        //升級最新版本需加=============================================================
        List<MediaType> supportedMediaTypes = new ArrayList<>();
        supportedMediaTypes.add(MediaType.APPLICATION_JSON);
        supportedMediaTypes.add(MediaType.APPLICATION_ATOM_XML);
        supportedMediaTypes.add(MediaType.APPLICATION_FORM_URLENCODED);
        supportedMediaTypes.add(MediaType.APPLICATION_OCTET_STREAM);
        supportedMediaTypes.add(MediaType.APPLICATION_PDF);
        supportedMediaTypes.add(MediaType.APPLICATION_RSS_XML);
        supportedMediaTypes.add(MediaType.APPLICATION_XHTML_XML);
        supportedMediaTypes.add(MediaType.APPLICATION_XML);
        supportedMediaTypes.add(MediaType.IMAGE_GIF);
        supportedMediaTypes.add(MediaType.IMAGE_JPEG);
        supportedMediaTypes.add(MediaType.IMAGE_PNG);
        supportedMediaTypes.add(MediaType.TEXT_EVENT_STREAM);
        supportedMediaTypes.add(MediaType.TEXT_HTML);
        supportedMediaTypes.add(MediaType.TEXT_MARKDOWN);
        supportedMediaTypes.add(MediaType.TEXT_PLAIN);
        supportedMediaTypes.add(MediaType.TEXT_XML);
        fastConverter.setSupportedMediaTypes(supportedMediaTypes);

        //創建配置類
        FastJsonConfig fastJsonConfig = new FastJsonConfig();
        //修改配置返回內容的過濾
        //WriteNullListAsEmpty  ：List字段如果爲null,輸出爲[],而非null
        //WriteNullStringAsEmpty ： 字符類型字段如果爲null,輸出爲"",而非null
        //DisableCircularReferenceDetect ：消除對同一對象循環引用的問題，默認爲false（如果不配置有可能會進入死循環）
        //WriteNullBooleanAsFalse：Boolean字段如果爲null,輸出爲false,而非null
        //WriteMapNullValue：是否輸出值爲null的字段,默認爲false
        fastJsonConfig.setSerializerFeatures(
                SerializerFeature.DisableCircularReferenceDetect,
                SerializerFeature.WriteMapNullValue
        );
        fastConverter.setFastJsonConfig(fastJsonConfig);

        return fastConverter;
    }
}