Spring Cloud Gateway 全局过滤器实现

在构建微服务架构时，Spring Cloud Gateway 作为服务网关，承担着路由转发、权限校验等职责。

全局过滤器（Global Filter）是 Spring Cloud Gateway 中用于处理跨服务的通用逻辑的组件，例如权限验证、日志记录等。

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.http.HttpStatus;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.stereotype.Component;
import org.springframework.util.AntPathMatcher;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;

import java.nio.charset.StandardCharsets;

@Component
public class GlobalAuthFilter implements GlobalFilter, Ordered {

    private AntPathMatcher antPathMatcher = new AntPathMatcher();

    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        ServerHttpRequest serverHttpRequest = exchange.getRequest();
        String path = serverHttpRequest.getURI().getPath();
        // 判断路径中是否包含 "inner"，只允许内部调用
        if (antPathMatcher.match("/**/inner/**", path)) {
            ServerHttpResponse response = exchange.getResponse();
            response.setStatusCode(HttpStatus.FORBIDDEN);
            DataBufferFactory dataBufferFactory = response.bufferFactory();
            DataBuffer dataBuffer = dataBufferFactory.wrap("无权限".getBytes(StandardCharsets.UTF_8));
            return response.writeWith(Mono.just(dataBuffer));
        }
        // 统一权限校验，此处应添加JWT等验证逻辑
        // todo 统一权限校验，通过 JWT 获取登录用户信息
        return chain.filter(exchange);
    }

    /**
     * 设置过滤器的优先级
     * 值越小，优先级越高
     * @return
     */
    @Override
    public int getOrder() {
        return 0;
    }
}