Spring使用Feign代理Http请求

前言

在 spring-cloud 中，大家会用 feign 远程调用，以下记录下在 springboot 中代理http简单调用

实现1

pom.xml

<dependency>
    <groupId>io.github.openfeign</groupId>
    <artifactId>feign-core</artifactId>
    <version>11.0</version>
</dependency>

服务提供方

/**
 * @since 2020-11-18
 * 服务方
 */
@RestController
@RequestMapping("/feign")
public class FeignController {

    @GetMapping("/get/{id}")
    public String test1(@PathVariable Integer id) {
        return "id1=" + id;
    }

    @GetMapping("/get")
    public String test2(@RequestParam Integer id) {
        return "id2=" + id;
    }
}

服务消费方

/**
 * 消费方
 * @since 2020-11-18
 */
public interface TestService {

    //直接url path中添加参数
    @RequestLine("GET /feign/get/{id}")
    String test1(@Param("id") Integer id);

    //url带参数
    @RequestLine("GET /feign/get?id={id}")
    String test2(@Param("id") Integer id);
}

测试

class TestServiceTest {

    @Test
    void test1() {
        TestService testService = Feign.builder().target(TestService.class, "http://127.0.0.1:8080");
        String ret = testService.test1(1);
        System.out.println(ret);
    }

    @Test
    void test2() {
        TestService testService = Feign.builder().target(TestService.class, "http://127.0.0.1:8080");
        String ret = testService.test2(2);
        System.out.println(ret);
    }
}

实现2

pom.xml

<!-- https://mvnrepository.com/artifact/org.springframework.cloud/spring-cloud-starter-openfeign -->
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-openfeign</artifactId>
    <version>2.2.6.RELEASE</version>
</dependency>
<!-- https://mvnrepository.com/artifact/io.github.openfeign/feign-okhttp -->
<dependency>
    <groupId>io.github.openfeign</groupId>
    <artifactId>feign-okhttp</artifactId>
    <version>11.0</version>
</dependency>

application.properties

feign.httpclient.enabled=false
feign.okhttp.enabled=true

// 启动
@EnableFeignClients

feign

@Configuration
@ConditionalOnClass(Feign.class)
@AutoConfigureBefore(FeignAutoConfiguration.class)
public class FeignOkHttpConfig {

    @Bean
    public okhttp3.OkHttpClient okHttpClient(){
        return new okhttp3.OkHttpClient.Builder()
                .readTimeout(60, TimeUnit.SECONDS)
                .connectTimeout(60, TimeUnit.SECONDS)
                .writeTimeout(120, TimeUnit.SECONDS)
                .connectionPool(new ConnectionPool())
                .build();
    }
}

feign代理

/**
 * @since 2020-11-18
 *
 * 调用方
 */
@FeignClient(name = "feignClientProxy",url = "http://localhost:8080")
public interface FeignClientProxy {

    @RequestMapping(value = "/feign/get", method = RequestMethod.GET)
    @ResponseBody
    String invoke(@RequestParam(value="id") Integer id);

    /**
     * 容错处理类，当调用失败时 返回空字符串
     */
    @Component
    class DefaultFallback implements FeignClientProxy {
        @Override
        public String invoke(@RequestParam(value="id") Integer id){
            return "err";
        }
    }
}

调用方

/**
 * 调用方
 * @since 2020-11-18
 */
@Controller
@RequestMapping("/demo")
public class FeignDemoController {

    @Autowired
    FeignClientProxy feignClientProxy;

    // http://localhost:8080/demo/feign?id=3
    @RequestMapping(value = "feign")
    @ResponseBody
    public String testFeign(@RequestParam(name = "id") Integer id) throws JsonProcessingException {
        ObjectMapper objectMapper = new ObjectMapper();
        String respResponseBody = feignClientProxy.invoke(id);
        return "调用结果:" + objectMapper.writeValueAsString(respResponseBody);

    }
}