2020-07-08---gateway

1.什么是gateway：
服务网关：它是基于spring5.0、spring boot2.0，和reactor开发的服务网关，它是基于filter提供了网关的基本功能：安全、监控、限流。
它分为：路由、断言、拦截

2.配置网关服务：首先pom文件中需要配置相关依赖。需要删除spring boot web和actor相关依赖。否则会启动失败

 <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-gateway</artifactId>
        </dependency>


基于路劲的网关配置：
spring:
  application:
    name: spring-cloud-gateway
  cloud:
    gateway:
      routes:
      - id: spring-cloud-gateway
        uri: http://localhost:8888
        predicates:
        - Path=/testGateway

3.自定义网关拦截器：

package com.shuai1.fileter;

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.stereotype.Component;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;
import sun.net.www.http.HttpClient;

//自定义的拦截器
@Component
public class Myfilter implements GlobalFilter, Ordered {
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
//获取username参数
        String username= exchange.getRequest().getQueryParams().getFirst("username");
//判断，为空的话返回相应的响应
        if(username==null){
            System.out.println("非法的用户，不能为空");
            exchange.getResponse().setStatusCode(HttpStatus.NOT_ACCEPTABLE);
            return exchange.getResponse().setComplete();
        }
        return chain.filter(exchange);
    }

    public int getOrder() {
        return 0;
    }
}