如何在Spring Cloud Gateway GlobalFilter中获取当前Trace ID

import org.springframework.cloud.gateway.filter.GatewayFilter;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.core.Ordered;
import org.springframework.stereotype.Component;
import org.springframework.web.server.ServerWebExchange;

@Component
public class TraceIdFilter implements GatewayFilter, Ordered {

    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        // 在这里获取当前的Trace ID
        String traceId = exchange.getRequest().getHeaders().getFirst("X-B3-TraceId");
        
        // 可以根据需要对Trace ID进行处理
        
        // 将Trace ID添加到请求头中，以便后续的服务可以使用
        exchange.getRequest().mutate().header("X-Trace-Id", traceId);
        
        // 继续执行过滤器链
        return chain.filter(exchange);
    }

    @Override
    public int getOrder() {
        // 设置过滤器的执行顺序
        return Ordered.HIGHEST_PRECEDENCE;
    }
}