Feign Dynamic URL

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Project Directory

Maven Dependency

 <?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">
     <modelVersion>4.0.0</modelVersion>

     <groupId>org.fool.feign</groupId>
     <artifactId>hello-feign</artifactId>
     <version>1.0-SNAPSHOT</version>

     <parent>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-parent</artifactId>
         <version>2.2.0.RELEASE</version>
     </parent>

     <dependencies>
         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-web</artifactId>
             <exclusions>
                 <exclusion>
                     <groupId>org.springframework.boot</groupId>
                     <artifactId>spring-boot-starter-tomcat</artifactId>
                 </exclusion>
             </exclusions>
         </dependency>

         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-jetty</artifactId>
             <exclusions>
                 <exclusion>
                     <groupId>org.eclipse.jetty.websocket</groupId>
                     <artifactId>websocket-server</artifactId>
                 </exclusion>
                 <exclusion>
                     <groupId>org.eclipse.jetty.websocket</groupId>
                     <artifactId>javax-websocket-server-impl</artifactId>
                 </exclusion>
             </exclusions>
         </dependency>

         <dependency>
             <groupId>org.projectlombok</groupId>
             <artifactId>lombok</artifactId>
         </dependency>

         <dependency>
             <groupId>org.springframework.cloud</groupId>
             <artifactId>spring-cloud-starter-openfeign</artifactId>
             <version>2.1.3.RELEASE</version>
         </dependency>

         <dependency>
             <groupId>com.google.code.gson</groupId>
             <artifactId>gson</artifactId>
         </dependency>

         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-test</artifactId>
             <scope>test</scope>
         </dependency>
     </dependencies>

     <build>
         <plugins>
             <plugin>
                 <groupId>org.springframework.boot</groupId>
                 <artifactId>spring-boot-maven-plugin</artifactId>
             </plugin>
         </plugins>
     </build>
 </project>

application.properties

 server.port=8188

 feign.hystrix.enabled=true
 hystrix.command.default.execution.isolation.thread.timeoutInMilliseconds=10000
 hystrix.threadpool.default.coreSize=10

Source Code

Application.java

 package org.fool.feign;

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

 @SpringBootApplication
 @EnableFeignClients
 public class Application {
     public static void main(String[] args) {
         SpringApplication.run(Application.class, args);
     }
 }

Note: 使用Feign需要加上 @EnableFeignClients 注解

AbstractFallbackFactory.java

 package org.fool.feign.client;

 import feign.hystrix.FallbackFactory;
 import org.fool.feign.common.LogDomain;
 import org.fool.feign.common.ResultCode;
 import org.fool.feign.contract.response.ApplicationResponse;
 import org.fool.feign.logger.ApplicationLogger;
 import org.fool.feign.logger.ApplicationLoggerFactory;
 import org.fool.feign.util.JsonUtils;

 public abstract class AbstractFallbackFactory<T> implements FallbackFactory<T> {
     protected final ApplicationLogger LOGGER = ApplicationLoggerFactory.getLogger(getClass());
     private static final String DEFAULT_MESSAGE = "isolation by hystrix";

     String handleExceptions(Throwable cause, String message) {
         LOGGER.error(LogDomain.CLIENT, message, cause);

         ApplicationResponse response = ApplicationResponse.builder()
                 .resultCode(ResultCode.INTERNAL_ERROR)
                 .message(ResultCode.INTERNAL_ERROR + ":" + DEFAULT_MESSAGE)
                 .build();

         return JsonUtils.objectToJson(response);
     }
 }

OrderClient.java

 package org.fool.feign.client;

 import org.fool.feign.config.FeignConfiguration;
 import org.fool.feign.contract.request.DemoRequest;
 import org.springframework.cloud.openfeign.FeignClient;
 import org.springframework.stereotype.Component;
 import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestBody;

 import java.net.URI;

 @FeignClient(name = "ORDER-SERVICE", url = "url-placeholder",
         fallbackFactory = OrderClient.OrderClientFallbackFactory.class, configuration = FeignConfiguration.class)
 public interface OrderClient {

     @PostMapping(value = "/demo")
     String queryOrder(URI uri, @RequestBody DemoRequest orderRequest);

     @Component
     class OrderClientFallbackFactory extends AbstractFallbackFactory<OrderClient> {
         @Override
         public OrderClient create(Throwable throwable) {
             return new OrderClient() {
                 @Override
                 public String queryOrder(URI uri, DemoRequest orderRequest) {
                     String message = "failed to query_order with " + orderRequest + " url: " + uri.toString();
                     return handleExceptions(throwable, message);
                 }
             };
         }
     }
 }

Note:

通常第一个红框输入的是远程服务的URL，第二个红框则没有URI uri 参数，这里为了实现远程调用模版接口相同，请求URL不同，采用如下图所示实现

ApplicationTest.java

 package org.fool.feign.test;

 import org.fool.feign.Application;
 import org.fool.feign.client.OrderClient;
 import org.fool.feign.contract.request.DemoRequest;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.context.SpringBootTest;
 import org.springframework.test.context.junit4.SpringRunner;

 import java.net.URI;

 @RunWith(SpringRunner.class)
 @SpringBootTest(classes = Application.class)
 public class ApplicationTest {

     @Autowired
     private OrderClient orderClient;

     @Test
     public void test() throws Exception {
         String url = "http://localhost:8188/order/v1/resource";

         DemoRequest request = new DemoRequest();
         request.setOrderTime("2019-11-11");
         request.setBizTag("order");

         String result = orderClient.queryOrder(new URI(url), request);
         System.out.println(result);
     }
 }

Note: 实现动态调用如下图红框所示，动态传如一个URL

Console Output