spring cloud gateway WebFilter 比 GlobalFilter 早，并且 能作用于所有的 请求 包含 gateway项目里的 controller

ServerHttpResponse 没有body 只能从 DataBuffer里取 或者 放入

import cn.hutool.core.util.StrUtil;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.ObjectNode;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.http.HttpCookie;
import org.springframework.http.HttpStatus;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.stereotype.Component;
import org.springframework.web.server.ServerWebExchange;
import org.springframework.web.server.WebFilter;
import org.springframework.web.server.WebFilterChain;
import reactor.core.publisher.Mono;

import java.nio.charset.StandardCharsets;

@Component
public class JWTFilters implements WebFilter {
    private final Logger logger = LoggerFactory.getLogger(JWTFilters.class);

    @Override
    public Mono<Void> filter(ServerWebExchange exchange, WebFilterChain chain) {
        ServerHttpRequest request = exchange.getRequest();
        HttpCookie tokenCookie = exchange.getRequest().getCookies().getFirst("token");
        logger.info("cookie {}", tokenCookie);
        String pathStr = request.getPath().toString();
        if (tokenCookie != null && !StrUtil.isBlank(tokenCookie.getValue())) {
            // 校验 token
        } else {
            if (pathStr.startsWith("/login")) {
                // 调用登录 验证
            } else {
                // 需要登录
                ServerHttpResponse res = exchange.getResponse();
                res.setStatusCode(HttpStatus.UNAUTHORIZED);


                ObjectMapper resJSONMap = new ObjectMapper();

                ObjectNode resJSON = resJSONMap.createObjectNode();
                resJSON.put("retCode", "-1");
                resJSON.put("retMsg", "认证失败，缺少token");

                try {
                    // ServerHttpResponse 没有body 只能从 DataBuffer里取 或者 放入
                    String resStr = resJSONMap.writerWithDefaultPrettyPrinter().writeValueAsString(resJSON);
                    DataBuffer db = res.bufferFactory().wrap(resStr.getBytes(StandardCharsets.UTF_8));
                    return res.writeWith(Mono.just(db));
                } catch (JsonProcessingException e) {
                    logger.info("JSON 转换失败: {0}", e);
                    throw new RuntimeException(e);
                }

            }
        }

        logger.info(request.getPath().toString());
        logger.info("JWT Filters");
        return chain.filter(exchange);
    }
}