获取SpringCloud gateway 响应的response的值，可以查看、修改

gateway获取、修改客户端请求Request的参数，我们在上一篇已经讲过了。那么网关发起请求后，微服务返回回来的response的值，还是要经过网关才发给客户端的。很多时候，我们希望能看到响应的值，或者修改它。那么怎么做呢？

    import org.reactivestreams.Publisher;
    import org.springframework.cloud.gateway.filter.GatewayFilterChain;
    import org.springframework.cloud.gateway.filter.GlobalFilter;
    import org.springframework.core.Ordered;
    import org.springframework.core.io.buffer.DataBuffer;
    import org.springframework.core.io.buffer.DataBufferFactory;
    import org.springframework.core.io.buffer.DataBufferUtils;
    import org.springframework.http.server.reactive.ServerHttpResponse;
    import org.springframework.http.server.reactive.ServerHttpResponseDecorator;
    import org.springframework.stereotype.Component;
    import org.springframework.web.server.ServerWebExchange;
    import reactor.core.publisher.Flux;
    import reactor.core.publisher.Mono;
     
    import java.nio.charset.Charset;
     
    /**
     * @author wuweifeng wrote on 2018/10/31.
     */
    @Component
    public class WrapperResponseGlobalFilter implements GlobalFilter, Ordered {
        @Override
        public int getOrder() {
            // -1 is response write filter, must be called before that
            return -2;
        }
     
        @Override
        public Mono filter(ServerWebExchange exchange, GatewayFilterChain chain) {
            ServerHttpResponse originalResponse = exchange.getResponse();
            DataBufferFactory bufferFactory = originalResponse.bufferFactory();
            ServerHttpResponseDecorator decoratedResponse = new ServerHttpResponseDecorator(originalResponse) {
                @Override
                public Mono writeWith(Publisher