6

无法让 Feign Client 工作。首先尝试使用 POST。不断遇到与编码器/解码器相关的错误，说类型不正确。然后在github上找到了一个调用简单GET API的例子，决定试一试。仍然失败

在 Github 和在线上，我看到多个版本的 Feign Client Spring-Cloud、OpenFeign、Netflix.feign 有不同的版本。谁能描述一个应该用于生产的最好和稳定的 Feign 客户端是什么？

package com.paa.controllers;

import org.springframework.cloud.netflix.feign.FeignClient;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

@FeignClient (name="test-service",url="https://www.reddit.com/r")
public interface GetFeignClient {

     @RequestMapping(method = RequestMethod.GET, value = "/java.json")
     public String posts();
}

Controller:

@RestController
@RequestMapping("/some/api")
public class TestWLCController {

  @Autowired
  private GetFeignClient getFeignClient;

  .. some stuff


    @RequestMapping(value="/postSomething",method = RequestMethod.POST)
    @ApiOperation(value = "Configures something",
            notes = "basic rest controller for testing feign")

    public ResponseEntity<SomeResponse> feignPost(
            UriComponentsBuilder builder,
            @ApiParam(name = "myRequest", 
            value = "request for configuring something", 
            required = true)
            @Valid @RequestBody SomeRequest someRequest) {

        String resp = null;
        try {
            resp = getFeignClient.posts();
        } catch (Exception er) {
            er.printStackTrace();
        }

    }
}

应用：

尝试了所有可能的注释排列，认为它可以解决 AutoWire 的问题，但仍然失败

@Configuration
@ComponentScan
@EnableAutoConfiguration
//@EnableEurekaClient
@EnableFeignClients

//@SpringBootApplication
//@EnableFeignClients
//@EnableFeignClients(basePackages = {"com.paa.xenia.controllers", "com.paa.xenia.services"})
public class ServiceApplication extends SpringBootServletInitializer {

    @Override
    protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {

        return application.sources(XeniaServiceApplication.class);
    }

    public static void main(String[] args) {

        SpringApplication.run(ServiceApplication.class, args);
    }
}

2016-07-20 18:15:42.406[0;39m [31mERROR[0;39m [35m32749[0;39m [2m---[0;39m [2m[主][0;39m [36mo.s.boot .SpringApplication [0;39m [2m:[0;39m 应用程序启动失败

org.springframework.beans.factory.BeanCreationException：创建名为“testWLCController”的bean时出错：注入自动装配的依赖项失败；嵌套异常是 org.springframework.beans.factory.BeanCreationException：无法自动装配字段：私有 com.paa.controllers.GetFeignClient com.paa.controllers.TestWLCController.gfClient；嵌套异常是 org.springframework.beans.factory.BeanCreationException：创建名称为“com.aa..controllers.GetFeignClient”的 bean 时出错：FactoryBean 在创建对象时抛出异常；嵌套异常是 java.lang.NullPointerException at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:334) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE] at组织。run(SpringApplication.java:1180) [spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE] at com.paa.ServiceApplication.main(ServiceApplication.java:44) [bin/:na] 由：org.springframework.beans.factory.BeanCreationException：无法自动装配字段：私有com.paa.controllers.GetFeignClient com.paa.controllers.TestWLCController.gfClient；嵌套异常是 org.springframework.beans.factory.BeanCreationException：创建名称为“com.paa.controllers.GetFeignClient”的 bean 时出错：FactoryBean 在创建对象时抛出异常；嵌套异常是 java.lang.NullPointerException 在 org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:573) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE ] 在 org.springframework.beans。

4

3 回答 3

4

我不确定您是否最终自己弄清楚了，但是为了其他可能偶然发现此线程的人，下面是您尝试做的工作示例。我将首先指出一些不正确的事情，或者至少在你的代码中不需要，然后展示我的代码。

  1. 您应该尽量不要使用该url属性。<feign client name>.ribbon.listOfServers相反，使用in bootstrap.yml（或bootstrap.properties）设置服务器列表。这允许客户端负载平衡，因为listOfServers可以是逗号分隔的列表。
  2. 将 Ribbon 用于 HTTPS 连接，您需要指定 HTTP 连接不需要的两件事。端口，它是listOfServersand的一部分<feign client name>.ribbon.IsSecure: true。如果没有端口，则连接到端口 80，如果没有IsSecure，则使用 HTTP。

  3. 使用 测试curl，我发现 Reddit 需要很长时间才能响应。有关如何分解请求-响应周期所花费的总时间的详细信息，请参阅此 SO帖子。

    $ curl -v -H "User-Agent: Mozilla/5.0" -w "@curl-format.txt" -o /dev/null -s "https://www.reddit.com/r/java/top.json?count=1"
{ [2759 bytes data]
* Connection #0 to host www.reddit.com left intact
time_namelookup:     0.527
time_connect:        0.577
time_appconnect:     0.758
time_pretransfer:    0.758
time_redirect:       0.000
time_starttransfer: 11.189
                  ----------
time_total:         11.218

根据 Netflix Wiki，默认读取和连接超时为 3000 毫秒，因此除非您更改它们，否则您将始终超时。

  1. 您可能已经注意到我User-Agent在curl请求中指定了一个标头。那是因为 Reddis 似乎对此非常挑剔，如果没有指定，大多数时候会返回 HTTP 429“请求过多”。它们不会Retry-After在响应中返回标头，因此不知道您需要等待多长时间才能发出另一个请求。
  2. Spring Cloud Netflix 和 Netflix Feign 是开源的，所以一些（很多）耐心和调试技巧非常方便。

“谈话很便宜。给我看代码。” （托瓦兹，莱纳斯（2000-08-25））。

我使用出色的Spring Initializr站点生成了一个 Gradle 应用程序。这是文件中的一个片段build.gradle。

dependencies {
    compile('org.springframework.cloud:spring-cloud-starter-feign')
    compile('org.springframework.boot:spring-boot-starter-web')
    testCompile('org.springframework.boot:spring-boot-starter-test')
}

dependencyManagement {
    imports {
        mavenBom "org.springframework.cloud:spring-cloud-dependencies:Camden.SR3"
    }
}

假装客户端：

@FeignClient(name = "reddit")
public interface RedditClient {
    @RequestMapping(method = GET, value = "/r/java/top.json?count=1",
            headers = {USER_AGENT + "=Mozilla/5.0", ACCEPT + "=" + APPLICATION_JSON_VALUE})
    public String posts();
}

启动应用程序：

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

    @RestController
    static class DemoController {
        @Autowired
        private RedditClient redditClient;

        @GetMapping("/posts")
        public String posts() {
            return redditClient.posts();
        }
    }
}

bootstrap.yml：

reddit:
  ribbon:
    listOfServers: www.reddit.com:443
    ConnectTimeout: 20000
    ReadTimeout: 20000
    IsSecure: true
hystrix.command.default.execution:
  timeout.enabled: true
  isolation.thread.timeoutInMilliseconds: 50000

集成测试：

@RunWith(SpringRunner.class)
@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
public class DemoApplicationTest {
    @Autowired
    private TestRestTemplate restTemplate;

    @Test
    public void testGetPosts() {
        ResponseEntity<String> responseEntity = restTemplate.getForEntity("/posts", String.class);

        HttpStatus statusCode = responseEntity.getStatusCode();
        assertThat(String.format("Actual status code: %d, reason: %s.",
                statusCode.value(), statusCode.getReasonPhrase()),
                statusCode.is2xxSuccessful(), equalTo(true));
    }
}
于 2016-12-13T03:44:07.540 回答
1

依赖项：

<dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
        </dependency>

         <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-parent</artifactId>
                <version>Greenwich.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

应用程序：

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.openfeign.EnableFeignClients;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

import com.test.cloud.bookservice.models.Book;

@SpringBootApplication
@RestController
@RequestMapping("/books")
@EnableFeignClients
public class BookServiceApplication {

    Logger logger = LogManager.getLogger(BookServiceApplication.class);

    @Autowired
    private StoreClient storeClient;


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


    @GetMapping("/book")
    public Book findBook() {
            return this.restTemplate.getForObject("http://stores/book", Book.class);
    }

    @FeignClient(name = "StoreClient", url = "127.0.0.1:8089")
    interface StoreClient {
        @RequestMapping(method = RequestMethod.GET, value = "/stores/book", consumes = "application/json")
        Book getBook();
    }

}
于 2019-07-05T13:25:27.337 回答
0

有人有兴趣了解我们是如何做到的，所以为了他们的利益发布答案。

父模块

package com.hitech.module.base;

@EnableFeignClients
public abstract class BaseApplication extends SpringBootServletInitializer {
...
..
}

build.gradle:

buildscript {
    ext {
        springBootVersion = '1.3.5.RELEASE'
    }
    repositories {
        mavenCentral()
    }
    dependencies {
        classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
        classpath("io.spring.gradle:dependency-management-plugin:0.5.6.RELEASE")
    }
}
...
...

dependencies {
    compile('io.springfox:springfox-swagger-ui:2.5.0')
    compile('io.springfox:springfox-swagger2:2.5.0')
    compile('org.springframework.cloud:spring-cloud-starter-feign')

子模块

package com.hitech.module.app;

import com.hitech.module.base.BaseApplication;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.data.mongo.MongoDataAutoConfiguration;
import org.springframework.boot.autoconfigure.mongo.MongoAutoConfiguration;
import org.springframework.cloud.netflix.feign.EnableFeignClients;

@SpringBootApplication(exclude = {MongoDataAutoConfiguration.class, MongoAutoConfiguration.class},
        scanBasePackages = {"com.hitech.module.base", "com.hitech.module.app", })
@EnableFeignClients("com.hitech.module.app.clients")
public class MyServiceApplication extends BaseApplication {

    private static final Logger LOG = LoggerFactory.getLogger(MyServiceApplication.class);

    public static void main(String[] args) {

        String s1 = "google";

        LOG.info ("=== Started Orchestration Service ===");
        SpringApplication.run(MyServiceApplication.class, args);


    }
}

引导程序.yml

feign:
  hystrix:
    enabled: false
datasource:
  audit:
    mongodb:
      host: localhost
      port: 27019
      database: audit
于 2017-05-11T21:37:42.120 回答