（一）Feign之支持文件上传和使用对象作为参数接收（一）Feign之支持文件上传和使

一、需求描述
1、需要支持文件上传。
2、使用实体类的对象作为参数传递。
3、POST请求方式为Form表单提交。Content-Type: application/x-www-form-urlencoded。
二、术语解释
1、Logger.Level：日志级别
2、Retryer:重试机制
3、ErrorDecoder：错误解码器
4、Request.Options:
connectTimeoutMillis; // connectTimeout配置项
readTimeoutMillis; // readTimeout配置项
5、RequestInterceptor：请求拦截器
6、Contract:：处理Feign接口注解，Spring Cloud Feign 使用SpringMvcContract 实现，处理Spring mvc 注解，也就是我们为什么可以用Spring mvc 注解的原因。
7、Client：Http客户端接口，默认是Client.Default，但是我们是不使用它的默认实现，Spring Cloud Feign为我们提供了okhttp3和ApacheHttpClient两种实现方式，只需使用maven引入以下两个中的一个依赖即可,版本自由选择。
8、Encoder：编码器，将一个对象转换成http请求体中， Spring Cloud Feign 使用 SpringEncoder
9、Decoder：解码器，将一个http响应转换成一个对象，Spring Cloud Feign 使用 ResponseEntityDecoder
10、FeignLoggerFactory：日志工厂
11、Feign.Builder：Feign接口构建类，覆盖默认Feign.Builder，比如：HystrixFeign.Builder
12、FeignContext：管理了所有的java config 配置
三、具体实现

import com.fasterxml.jackson.core.JsonParser; import feign.Contract; import feign.Logger; import feign.codec.Decoder; import feign.codec.Encoder; import feign.form.FormEncoder; import org.springframework.beans.BeansException; import org.springframework.beans.factory.ObjectFactory; import org.springframework.boot.autoconfigure.http.HttpMessageConverters; import org.springframework.cloud.openfeign.AnnotatedParameterProcessor; import org.springframework.cloud.openfeign.annotation.PathVariableParameterProcessor; import org.springframework.cloud.openfeign.annotation.RequestHeaderParameterProcessor; import org.springframework.cloud.openfeign.annotation.RequestParamParameterProcessor; import org.springframework.cloud.openfeign.support.ResponseEntityDecoder; import org.springframework.cloud.openfeign.support.SpringDecoder; import org.springframework.cloud.openfeign.support.SpringEncoder; import org.springframework.cloud.openfeign.support.SpringMvcContract; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.http.MediaType; import org.springframework.http.converter.HttpMessageConverter; import org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter; import org.springframework.http.converter.json.Jackson2ObjectMapperBuilder; import java.util.ArrayList; import java.util.List; @Configuration public class FeignServiceConfiguration {HttpMessageConverter mappingJackson2HttpMessageConverter = new ContentTypeFixedJackson2HttpMessageConverter(); private static class ContentTypeFixedJackson2HttpMessageConverter extends AbstractJackson2HttpMessageConverter { public ContentTypeFixedJackson2HttpMessageConverter() { super(Jackson2ObjectMapperBuilder.json() .featuresToEnable(JsonParser.Feature.ALLOW_UNQUOTED_CONTROL_CHARS, JsonParser.Feature.ALLOW_BACKSLASH_ESCAPING_ANY_CHARACTER) .build(), MediaType.TEXT_HTML, MediaType.APPLICATION_JSON_UTF8, new MediaType("application", "*+json")); } }HttpMessageConverters messageConverters = new HttpMessageConverters(mappingJackson2HttpMessageConverter); ObjectFactory messageConvertersFactory = new ObjectFactory() { @Override public HttpMessageConverters getObject() throws BeansException { return messageConverters; } }; @Bean public Decoder feignDecoder() { return new ResponseEntityDecoder(new SpringDecoder(this.messageConvertersFactory)); }@Bean public Encoder feignEncoder() { return new FormEncoder(new SpringEncoder(messageConvertersFactory)); }/** * 开启Feign的日志 * * @return */ @Bean public Logger.Level logger() { return Logger.Level.FULL; } }

【（一）Feign之支持文件上传和使用对象作为参数接收】四、测试结果

...[TestFeignClient#post] ---> POST http://www.baidu.com/test HTTP/1.1 ...[TestFeignClient#post] Accept: application/json; charset=UTF-8 ...[TestFeignClient#post] Content-Type: application/x-www-form-urlencoded; charset=UTF-8 ...[TestFeignClient#post] Content-Length: 30 ...[TestFeignClient#post] ...[TestFeignClient#post] password=123456&username=admin ...[TestFeignClient#post] ---> END HTTP (30-byte body)