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