25.gateway的Filter 过滤器工厂（springcloud）

package com.it.filter;
 
import com.fasterxml.jackson.databind.ObjectMapper;
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.http.HttpHeaders;
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 reactor.core.publisher.Mono;
 
import java.net.URI;
import java.util.HashMap;
 
/**
 * 定义了一个过滤器，
 * 需要给该过滤器指定执行顺序，通常一个项目中有多个过滤器，组成过滤器的责任链模式。
 */
@Component
public class MyGlobalFilter implements GlobalFilter, Ordered {
 
    /**
     * 这个就是全部过滤的方法
     * 常用责任链模式
     * @param exchange
     * @param chain
     * @return
     */
    @lombok.SneakyThrows
    @Override
    public Mono filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        //针对请求的过滤，拿到请求 header url 参数
        ServerHttpRequest request = exchange.getRequest();
 
        String uri = request.getURI().getPath();
        System.out.println(uri);
        HttpHeaders headers = request.getHeaders();
        System.out.println(headers);
        String name = request.getMethod().name();
        System.out.println(name);
        String hostName = request.getRemoteAddress().getHostName();
        System.out.println(hostName);
 
        //响应相关的
        ServerHttpResponse response = exchange.getResponse();
 
        //放行,转入下一个过滤器
//        return chain.filter(exchange);
 
        //不放行
        response.getHeaders().set("content-type","application/json;charset=utf-8");
        //组装业务返回值
        HashMap map = new HashMap<>();
        map.put("code", HttpStatus.UNAUTHORIZED.value());
        map.put("msg","你未授权！");
        ObjectMapper objectMapper = new ObjectMapper();
        //因为返回类型为Mono，所以需要把map转换成一个字节
        byte[] bytes = objectMapper.writeValueAsBytes(objectMapper);
        //通过buffer工厂将字节数组包装成一个数据包
        DataBuffer wrap = response.bufferFactory().wrap(bytes);
        return response.writeWith(Mono.just(wrap));
 
 
    }
 
    /**
     * 指定过滤器执行顺序的方法
     * 越小越先执行
     * @return
     */
    @Override
    public int getOrder() {
        return -1;
    }
}