Spring Cloud Gateway 限流实战，终于有人写清楚了！

import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.core.io.buffer.DataBufferUtils;
import org.springframework.http.HttpStatus;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;
 
import java.nio.charset.StandardCharsets;
 
public class RequestRateLimiterFilter implements GlobalFilter {
 
    private final RequestRateLimiter requestRateLimiter;
 
    public RequestRateLimiterFilter(RequestRateLimiter requestRateLimiter) {
        this.requestRateLimiter = requestRateLimiter;
    }
 
    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        return requestRateLimiter.isAllowed(exchange)
                .flatMap(response -> {
                    if (response.isCommitted()) {
                        return Mono.error(new RuntimeException("Request rejected"));
                    }
 
                    ServerHttpResponse response = exchange.getResponse();
                    response.setStatusCode(HttpStatus.TOO_MANY_REQUESTS);
                    String result = "Requests too many";
                    response.getHeaders().setContentType(MediaType.APPLICATION_JSON);
                    DataBufferUtils.write(response.bufferFactory().wrap(result.getBytes(StandardCharsets.UTF_8)), response);
                    return response.setComplete();
                });
    }
}

这段代码实现了一个全局过滤器，用于Spring Cloud Gateway中的限流处理。它通过RequestRateLimiter组件的isAllowed方法检查请求是否超出了限制，并返回合适的响应。如果请求被拒绝，它将返回一个429 Too Many Requests响应，并显示一个错误信息。这是一个简洁且有教育意义的实现，对于需要在自己的项目中实现类似功能的开发者来说，值得借鉴。