微服务：Gateway统一拦截请求

1、在项目中新建gateway-server服务

 2、在gateway-server中引入nacos和gateway所需依赖

    com.alibaba.cloud
    spring-cloud-starter-alibaba-nacos-discovery




    org.springframework.cloud
    spring-cloud-starter-gateway



    com.alibaba.cloud
    spring-cloud-starter-alibaba-nacos-config

3、在nacos配置application.yml文件

spring:
  cloud:
    gateway:
      globalcors:
        add-to-simple-url-handler-mapping: true
        corsConfigurations:
          '[/**]':
            allowedHeaders: "*"
            allowedOrigins: "*"
            allowedMethods:
              - GET
              - POST
              - DELETE
              - PUT
              - OPTION
      routes:
        # 用户微服务
        - id: user
          uri: lb://leadnews-user
          predicates:
            - Path=/user/**
          filters:
            - StripPrefix= 1
        # 文章微服务
        - id: article
          uri: lb://leadnews-article
          predicates:
            - Path=/article/**
          filters:
            - StripPrefix= 1
        #搜索微服务
        - id: leadnews-search
          uri: lb://leadnews-search
          predicates:
            - Path=/search/**
          filters:
            - StripPrefix= 1
        #行为微服务
        - id: leadnews-behavior
          uri: lb://leadnews-behavior
          predicates:
            - Path=/behavior/**
          filters:
            - StripPrefix= 1
        #评论微服务
        - id: leadnews-comment
          uri: lb://leadnews-comment
          predicates:
            - Path=/comment/**
          filters:
            - StripPrefix= 1

4、在启动类添加开关注解 @EnableDiscoveryClient  //开启注册中心

package com.heima.app.gateway;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;

@SpringBootApplication
@EnableDiscoveryClient  //开启注册中心
public class AppGatewayApplication {

    public static void main(String[] args) {
        SpringApplication.run(AppGatewayApplication.class,args);
    }
}

5、新建AuthorizeFilter类实现请求拦截

        这里的业务场景是拦截除登录接口以外的接口，

        查看是否携带token，如果是则放行，否则返回错误

package com.heima.app.gateway.filter;


import com.heima.app.gateway.util.AppJwtUtil;
import io.jsonwebtoken.Claims;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang.StringUtils;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.core.Ordered;
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;

@Component
@Slf4j
public class AuthorizeFilter implements Ordered, GlobalFilter {
    @Override
    public Mono filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        //1.获取request和response对象
        ServerHttpRequest request = exchange.getRequest();
        ServerHttpResponse response = exchange.getResponse();

        //2.判断是否是登录
        if(request.getURI().getPath().contains("/login")){
            //放行
            return chain.filter(exchange);
        }


        //3.获取token
        String token = request.getHeaders().getFirst("token");

        //4.判断token是否存在
        if(StringUtils.isBlank(token)){
            response.setStatusCode(HttpStatus.UNAUTHORIZED);
            return response.setComplete();
        }

        //5.判断token是否有效
        try {
            Claims claimsBody = AppJwtUtil.getClaimsBody(token);
            //是否是过期
            int result = AppJwtUtil.verifyToken(claimsBody);
            if(result == 1 || result  == 2){
                response.setStatusCode(HttpStatus.UNAUTHORIZED);
                return response.setComplete();
            }
        }catch (Exception e){
            e.printStackTrace();
            response.setStatusCode(HttpStatus.UNAUTHORIZED);
            return response.setComplete();
        }

        //6.放行
        return chain.filter(exchange);
    }

    /**
     * 优先级设置  值越小  优先级越高
     * @return
     */
    @Override
    public int getOrder() {
        return 0;
    }
}

5、重启服务并测试