Spring Cloud OpenFeign中的请求头、参数和响应处理技巧

import feign.RequestInterceptor;
import feign.RequestTemplate;
import feign.Response;
import feign.codec.Decoder;
import feign.codec.Encoder;
import org.springframework.cloud.openfeign.support.SpringDecoder;
import org.springframework.cloud.openfeign.support.SpringEncoder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import feign.Feign;
 
@Configuration
public class FeignConfig {
 
    @Bean
    public Encoder feignEncoder() {
        return new SpringEncoder(feignHttpMessageConverter());
    }
 
    @Bean
    public Decoder feignDecoder() {
        return new SpringDecoder(feignHttpMessageConverter());
    }
 
    private ObjectFactory<HttpMessageConverters> feignHttpMessageConverter() {
        return new ObjectFactory<HttpMessageConverters>() {
            @Override
            public HttpMessageConverters getObject() {
                return new HttpMessageConverters(new AdditionalJackson2HttpMessageConverter());
            }
        };
    }
 
    @Bean
    public RequestInterceptor requestInterceptor() {
        return new RequestInterceptor() {
            @Override
            public void apply(RequestTemplate template) {
                template.header("Custom-Header", "value");
            }
        };
    }
 
    @Bean
    public Feign.Builder feignBuilder() {
        return Feign.builder()
                .encoder(feignEncoder())
                .decoder(feignDecoder())
                .requestInterceptor(requestInterceptor());
    }
}

这个配置类展示了如何自定义Feign的编码器、解码器和请求拦截器。在这个例子中，我们添加了一个自定义的请求头，并且使用了一个额外的消息转换器来处理特定的数据格式。这个配置可以用在需要对Feign客户端进行定制化配置的场景中。