1.什么是微服务网关

微服务网关是整个微服务API接口的入口。

可以实现：

API接口过滤

验证登录

解决跨域

日志拦截

权限控制

限流熔断

负载均衡

黑白名单机制

2.过滤器和网关的区别

过滤器局部拦截

网关全局拦截

3.zuul网关和gateway网关区别

gateway比zuul的性能要好很多。

zuul底层基于servlet实现，阻塞式api，不支持长连接

gateway基于spring5构建，响应式非阻塞api，支持长连接

4.网关与nginx区别

相同点：都可以实现api拦截，负载均衡，反向代理，请求过滤

不同点： gateway采用java语言编写 nginx采用c语言编写

5.搭建网关

1）pom依赖

<properties>
        <boot-version>2.1.11.RELEASE</boot-version>
    </properties>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.11.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <dependencies>
        <!--nacos-->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-alibaba-nacos-discovery</artifactId>
            <version>2.1.1.RELEASE</version>
        </dependency>
        <!--openfegin-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>
        <!--gateway -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-gateway</artifactId>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Greenwich.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>${boot-version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <dependency>
                <groupId>com.alibaba.cloud</groupId>
                <artifactId>spring-cloud-alibaba-dependencies</artifactId>
                <version>2.1.1.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

2）yml配置

server:
  port: 80
####服务网关名称
spring:
  application:
    name: demo-gateway
  cloud:
    gateway:
      ###路由策略
      routes:
        ###根据我们的服务名称查找地址实现调用
        - id: member
          ####转发 https://www.baidu.com/  http://127.0.0.1:8080/  lb://nacos-member/
          uri: lb://nacos-member/
          filters:
            - StripPrefix=1
          ###匹配规则
          predicates:
            - Path=/member/**
      discovery:
        locator:
          ###允许通过注册中心获取地址调用
          enabled: true
    nacos:
      discovery:
        server-addr: 127.0.0.1:8848

3）全局过滤

package com.demo.filter;

import org.apache.commons.lang3.StringUtils;
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.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;

/**
 * 全局过滤-验证token
 */
@Component
public class TokenGlobalFilter implements GlobalFilter, Ordered {
    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
//        //获取参数
//        String token = exchange.getRequest().getQueryParams().getFirst("token");
//        if (StringUtils.isEmpty(token)) {
//            ServerHttpResponse response = exchange.getResponse();
//            response.setStatusCode(HttpStatus.INTERNAL_SERVER_ERROR);
//            String msg = "token not is null ";
//            DataBuffer buffer = response.bufferFactory().wrap(msg.getBytes());
//            return response.writeWith(Mono.just(buffer));
//        }
        // 直接转发到真实服务
        return chain.filter(exchange);
    }

    @Override
    public int getOrder() {
        return 0;
    }
}

package com.demo.filter;

import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.http.HttpHeaders;
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;

/**
 * 全局过滤-跨域设置
 */
@Component
public class CrossOriginFilter implements GlobalFilter {

    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        ServerHttpRequest request = exchange.getRequest();
        ServerHttpResponse response = exchange.getResponse();
        HttpHeaders headers = response.getHeaders();
        headers.add(HttpHeaders.ACCESS_CONTROL_ALLOW_ORIGIN, "*");
        headers.add(HttpHeaders.ACCESS_CONTROL_ALLOW_METHODS, "POST, GET, PUT, OPTIONS, DELETE, PATCH");
        headers.add(HttpHeaders.ACCESS_CONTROL_ALLOW_CREDENTIALS, "true");
        headers.add(HttpHeaders.ACCESS_CONTROL_ALLOW_HEADERS, "*");
        headers.add(HttpHeaders.ACCESS_CONTROL_EXPOSE_HEADERS, "*");
        return chain.filter(exchange);

    }
}

4）启动

package com.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class AppGateWay {
    public static void main(String[] args) {
        SpringApplication.run(AppGateWay.class);
    }
}

5）测试

http://localhost/member/getUser?userId=1