自定义Feign客户端

一 介绍

默认使用HttpURLConnection连接HTTP服务

二 编写自定义客户端

1 增加依赖

            
                  org.apache.httpcomponents
                  httpclient
                  4.5.2
            

2 实现Client接口

package org.crazyit.cloud;

import java.io.IOException;
import java.net.URI;
import java.util.Collection;
import java.util.HashMap;

import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpRequestBase;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

import feign.Client;
import feign.Request;
import feign.Request.Options;
import feign.Response;

public class MyClient implements Client {

    public Response execute(Request request, Options options)
            throws IOException {
        System.out.println("this is my client");
        try {
            // 创建一个默认的客户端
            CloseableHttpClient httpclient = HttpClients.createDefault();
            // 获取调用的HTTP方法
            final String method = request.method();
            // 创建一个HttpClient的HttpRequest
            HttpRequestBase httpRequest = new HttpRequestBase() {
                public String getMethod() {
                    return method;
                }
            };
            // 设置请求地址
            httpRequest.setURI(new URI(request.url()));
            // 执行请求，获取响应
            HttpResponse httpResponse = httpclient.execute(httpRequest);
            // 获取响应的主体内容
            byte[] body = EntityUtils.toByteArray(httpResponse.getEntity());
            // 将HttpClient的响应对象转换为Feign的Response
            Response response = Response.builder()
                    .body(body)
                    .headers(new HashMap>())
                    .status(httpResponse.getStatusLine().getStatusCode())
                    .build();
            return response;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

}

3 编写测试类

package org.crazyit.cloud;
import feign.Feign;
public class MyClientTest {
      public static void main(String[] args) {
            HelloClient client = Feign.builder()
                        .client(new MyClient())
                        .target(HelloClient.class,
                        "http://localhost:8080");
            String result = client.hello();
            System.out.println(result);
      }
}

4 启动微服务

5 测试结果

this is my client

Hello World