diff --git a/assets/feign工作流程.png b/assets/feign工作流程.png new file mode 100644 index 0000000..6fe26a2 Binary files /dev/null and b/assets/feign工作流程.png differ diff --git a/changelog.md b/changelog.md index d5939f8..2e3e6e3 100644 --- a/changelog.md +++ b/changelog.md @@ -475,16 +475,16 @@ spring: Port of the service provider: 19922 ``` - # [集成ribbon实现客户端负载均衡](#集成ribbon实现客户端负载均衡) > 代码分支: load-balancer ## 关于ribbon -> (翻译自官方文档)ribbon是一个提供如下功能的依赖包: -> - 负载均衡 -> - 容错机制 -> - 支持多种协议(HTTP, TCP, UDP)，支持异步和响应式的调用方式 -> - 缓存和批处理 + +(翻译自官方文档)ribbon是一个提供如下功能的依赖包: +- 负载均衡 +- 容错机制 +- 支持多种协议(HTTP, TCP, UDP)，支持异步和响应式的调用方式 +- 缓存和批处理 #### ribbon核心API @@ -971,6 +971,74 @@ public class ConsumerApplication { 访问```http://localhost:8080/foo``` +# [集成Feign简化调用方式](#集成Feign简化调用方式) +> 代码分支: open-feign + +## 关于feign +[Open Feign](https://github.com/OpenFeign/feign) 是一个简化http调用方式的Java客户端，通过处理接口的注解生成响应报文。使用示例: + +```java +interface HelloService { + + @RequestLine("GET /hello") + String hello(); +} + +@Test +public void testOpenFeign() { + HelloService helloService = Feign.builder() + .target(HelloService.class, "http://localhost:8080"); + String response = helloService.hello(); +} +``` + +Spring Cloud基于Open Feign开发了[Spring Cloud OpenFeign](https://github.com/spring-cloud/spring-cloud-openfeign) ，得以支持Spring Mvc的注解（通过实现feign的Contract接口，实现类为SpringMvcContract），使用示例: + +```java +interface WorldService { + + @GetMapping("/world") + String world(); +} + +@Test +public void testSpringCloudOpenFeign() { + WorldService worldService = Feign.builder() + .contract(new SpringMvcContract()) + .target(WorldService.class, "http://localhost:8080"); + String response = worldService.world(); +} +``` + +可以dubug上面两个示例，代码放在测试类FeignTest中，重点关注Contract接口对注解的解析 + + +#### Open Feign核心API + +Open Feign工作流程: + +![](./assets/feign工作流程.png) + +一、Contract接口 + +负责解析Feign客户端接口的类注解、方法注解和参数。实现类```feign.Contract.Default```支持Open Feign的注解，比如上面第一个示例中的RequestLine注解；Spring Cloud OpenFeign开发的实现类```SpringMvcContract```支持Spring MVC的注解，如GetMapping、PostMapping、RequestMapping。 + +二、Encoder接口 + +编码器，将请求对象编码为请求体 + +三、Decoder接口 + +解码器，将响应体解码为对象 + +四、RequestInterceptor拦截器接口 + +对请求进行拦截处理 + +五、Client接口 + +提交http请求的接口 + diff --git a/mini-spring-cloud-openfeign/src/main/java/com/github/cloud/openfeign/ribbon/LoadBalancerFeignClient.java b/mini-spring-cloud-openfeign/src/main/java/com/github/cloud/openfeign/ribbon/LoadBalancerFeignClient.java index c347068..d172492 100644 --- a/mini-spring-cloud-openfeign/src/main/java/com/github/cloud/openfeign/ribbon/LoadBalancerFeignClient.java +++ b/mini-spring-cloud-openfeign/src/main/java/com/github/cloud/openfeign/ribbon/LoadBalancerFeignClient.java @@ -1,8 +1,5 @@ package com.github.cloud.openfeign.ribbon; -import com.netflix.client.ClientException; -import com.netflix.client.ClientRequest; -import com.netflix.client.IResponse; import feign.Client; import feign.Request; import feign.Response; @@ -13,7 +10,6 @@ import java.io.IOException; import java.net.URI; import java.nio.charset.StandardCharsets; import java.util.HashMap; -import java.util.Map; /** * 具备负载均衡能力的feign client @@ -32,81 +28,23 @@ public class LoadBalancerFeignClient implements Client { this.delegate = delegate; } + @SuppressWarnings("deprecation") @Override public Response execute(Request request, Request.Options options) throws IOException { - //客户端负载均衡 - URI original = URI.create(request.url()); - String serviceId = original.getHost(); - //选择服务实例 - ServiceInstance serviceInstance = loadBalancerClient.choose(serviceId); - //重建请求URI - URI uri = loadBalancerClient.reconstructURI(serviceInstance, original); - - Response response = delegate.execute(new RibbonRequest(request, uri).toRequest(), options); - return new RibbonResponse(uri, response).getResponse(); - } - - private static class RibbonRequest extends ClientRequest { - - private Request request; - - public RibbonRequest(Request request, URI uri) { - this.request = request; - setUri(uri); - } - - @SuppressWarnings("deprecation") - private Request toRequest() { - return Request.create(request.httpMethod(), getUri().toASCIIString(), new HashMap<>(), + try { + //客户端负载均衡 + URI original = URI.create(request.url()); + String serviceId = original.getHost(); + //选择服务实例 + ServiceInstance serviceInstance = loadBalancerClient.choose(serviceId); + //重建请求URI + URI uri = loadBalancerClient.reconstructURI(serviceInstance, original); + + Request newRequest = Request.create(request.httpMethod(), uri.toASCIIString(), new HashMap<>(), request.body(), StandardCharsets.UTF_8); - } - } - - private static class RibbonResponse implements IResponse { - - private final URI uri; - - private final Response response; - - protected RibbonResponse(URI uri, Response response) { - this.uri = uri; - this.response = response; - } - - @Override - public Object getPayload() throws ClientException { - return response.body(); - } - - @Override - public boolean hasPayload() { - return response.body() != null; - } - - @Override - public boolean isSuccess() { - return response.status() == 200; - } - - @Override - public URI getRequestedURI() { - return uri; - } - - @Override - public Map getHeaders() { - return new HashMap<>(); - } - - @Override - public void close() throws IOException { - if (response != null && response.body() != null) { - response.body().close(); - } - } - - public Response getResponse() { - return response; + return delegate.execute(newRequest, options); + } catch (IOException e) { + throw new RuntimeException(e); } } }