从零开始学习 Spring Cloud Gateway：打造可扩展的微服务网关

<dependencies>
  <!--nacos服务发现依赖-->
  <dependency>
      <groupId>com.alibaba.cloud</groupId>
      <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
  </dependency>

  <dependency>
      <groupId>org.springframework.cloud</groupId>
      <artifactId>spring-cloud-starter-gateway</artifactId>
  </dependency>
  <dependency>
      <groupId>org.springframework.cloud</groupId>
      <artifactId>spring-cloud-starter-loadbalancer</artifactId>
  </dependency>
</dependencies>
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package com.zbbmeta.gateway;

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

/**
 * @author springboot葵花宝典
 * @description: TODO
 */
@SpringBootApplication
public class GatewayApplication {
    public static void main(String[] args) {
        SpringApplication.run(GatewayApplication.class,args);
    }
}
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server:
  port: 9999 # 网关端口
spring:
  application:
    name: gateway-service # 服务名称
  cloud:
    nacos:
      server-addr: localhost:8848 # nacos地址
    # 开启nacos负载均衡策略
    loadbalancer:
      nacos:
        enabled: true
    gateway:
      routes: # 网关路由配置
        - id: user-service # 路由id，自定义，只要唯一即可
          #uri: http://127.0.0.1:8088 # 路由的目标地址 http就是固定地址
          uri: lb://user-service # 路由的目标地址 lb就是负载均衡，后面跟服务名称
          predicates: # 路由断言，也就是判断请求是否符合路由规则的条件
            - Path=/user/** # 这个是按照路径匹配，只要以/user/开头就符合要求
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spring:
  cloud:
    gateway:
      routes:
      - id: header_route
        uri: https://example.org
        predicates:
        - Header=X-Request-Id, \d+
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spring:
  cloud:
    gateway:
      routes:
      - id: user-service 
        uri: lb://userservice 
        predicates: 
        - Path=/user/** 
        filters: # 过滤器
        - AddRequestHeader=Learn, learn springboot! # 添加请求头
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@GetMapping("/{id}")
public User test(@PathVariable("id") Long id, HttpServletRequest httpRequest){
    String learn = httpRequest.getHeader("Learn");

    System.out.println("Learn = " + learn);


    User user = userService.getById(id);

    return user;
}
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spring:
    gateway:
      routes: # 网关路由配置
      - id: user-service # 路由id，自定义，只要唯一即可
        #uri: http://127.0.0.1:8088 # 路由的目标地址 http就是固定地址
        uri: lb://user-service # 路由的目标地址 lb就是负载均衡，后面跟服务名称
        predicates: # 路由断言，也就是判断请求是否符合路由规则的条件
          - Path=/user/** # 这个是按照路径匹配，只要以/user/开头就符合要求
      default-filters: # 默认过滤项
        - AddRequestHeader=Learn, learn springbot! # 添加请求头
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public interface GlobalFilter {
    /**
     *  处理当前请求，有必要的话通过{@link GatewayFilterChain}将请求交给下一个过滤器处理
     *
     * @param exchange 请求上下文，里面可以获取Request、Response等信息
     * @param chain 用来把请求委托给下一个过滤器 
     * @return {@code Mono<Void>} 返回标示当前过滤器业务结束
     */
    Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain);
}
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package com.zbbmeta.gateway.filters;

import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.stereotype.Component;
import org.springframework.util.MultiValueMap;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;
import reactor.netty.http.server.HttpServerRequest;

import java.util.List;

/**
 * @author springboot葵花宝典
 * @description: TODO
 */
@Component
public class AuthorizeFilter implements GlobalFilter {
    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        // 1.获取请求头
        HttpHeaders headers = exchange.getRequest().getHeaders();
        // 2.获取请求头key是authorization
        List<String> auths = headers.get("authorization");
        // 3.校验
        if(auths.contains("admin")){
            // 放行
            return chain.filter(exchange);
        }
        // 4.拦截
        // 4.1.禁止访问，设置状态码
        exchange.getResponse().setStatusCode(HttpStatus.FORBIDDEN);
        // 4.2.结束处理
        return exchange.getResponse().setComplete();
    }
}
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