# Api 网关 **场景**：当我们在做接口平台的时候，我们需要在每一个接口结束调用相关的方法进行记录次数，但是这时候就有问题了，如果我们需要在每一个接口调用的时候到要执行的话难道不能「提取出来」吗？ 答案时肯定的，但是我们要用什么技术？AOP ？网关？ AOP 这个 Spring 非常重要的特性，那么该如何实现`这个项目`的相关接口执行之后调用统计方法呢？ ```java @Aspect @Component public class MethodExecutionCounterAspect { // 定义切点，可以根据自己的需求进行配置 @After("execution(* com.example.yourpackage.YourService.*(..))") public void afterMethodExecution(JoinPoint joinPoint) { // 记录方法执行次数 // 查询数据库进行加一 methodExecutionCount++; System.out.println("Method executed: " + joinPoint.getSignature()); System.out.println("Method execution count: " + methodExecutionCount); // 执行目标方法 Object result = joinPoint.proceed(); // 可以在这里添加额外的逻辑，根据需要修改 result return result; } } ``` ![](https://cdn.hashnode.com/res/hashnode/image/upload/v1695809092352/f12e8aa0-a305-4757-9d5d-11539b61297d.png align="center") 但是 AOP 也有缺点，只能在单个项目中使用，虽然我们可以封装成 SDK 但是还是需要在每一个项目中引入和调用，有没有更简单的呢？当然那就是 `网关`使用网关之后就可以做 \*\*「统一」\*\*管理 ![](https://cdn.hashnode.com/res/hashnode/image/upload/v1695809368884/af0747ff-73fb-4c94-b0fe-4f6e4ffb18bf.png align="center") # 网关 什么是网关？理解成火车站的检票口，**统一** 去检票。 ## 作用 统一去进行一些操作、处理一些问题。 比如： 1. 路由 2. 负载均衡 3. 统一鉴权 4. 跨域 5. 统一业务处理（缓存） 6. 访问控制 7. 发布控制 8. 流量染色 9. 接口保护 1. 限制请求 2. 信息脱敏 3. 降级（熔断） 4. 限流：学习令牌桶算法、学习漏桶算法，学习一下 RedisLimitHandler 5. 超时时间 10. 统一日志 11. 统一文档 ### 路由 起到`转发`的作用，比如有接口 A 和接口 B，网关会记录这些信息，根据用户访问的地址和参数，转发请求到对应的接口（服务器 / 集群） /a => 接口A /b => 接口 [官方文档](https://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#gateway-request-predicates-factories) 官方文档永远都是最重要的，记住这一点！ ### 负载均衡 在路由的基础上 /c => 服务 A / 集群 A（随机转发到其中的某一个机器） uri 从固定地址改成 lb:xxxx ### **统一处理跨域** 网关统一处理跨域，不用在每个项目里单独处理，这个的原因是网关一般是挡在最前面的原因。[文档](https://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#cors-configuration) ### **发布控制** 灰度发布，比如上线新接口，先给新接口分配 20% 的流量，老接口 80%，再慢慢调整比重。[文档](https://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#the-weight-route-predicate-factory) ```xml spring: cloud: gateway: routes: - id: weight_high uri: https://weighthigh.org predicates: - Weight=group1, 8 - id: weight_low uri: https://weightlow.org predicates: - Weight=group1, 2 ``` 这里的 `Weight=group1` 意识是把这两个断言设置成一组 ### **流量染色** 给请求（流量）添加一些标识，一般是设置请求头中，添加新的请求头。这样就可以区分是不是经过了网关，没有经过网关的就不会有对应的请求头，可以防止直接请求后端接口 [文档](https://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#cors-configuration) [全局染色](https://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#default-filters) ```xml spring: cloud: gateway: routes: - id: after_route # path 的内容会拼到这个的后面进行请求 uri: http://localhost:8123 predicates: - Path=/api/** # 流量染色 filters: - AddRequestHeader=yupi, handsome ``` ### **统一接口保护** 1. 限制请求：[https://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#requestheadersize-gatewayfilter-factory](https://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#requestheadersize-gatewayfilter-factory%EF%BF%BC2%E4%BF%A1%E6%81%AF%E8%84%B1%E6%95%8F%EF%BC%9Ahttps://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#the-removerequestheader-gatewayfilter-factory%EF%BF%BC3%E9%99%8D%E7%BA%A7%EF%BC%88%E7%86%94%E6%96%AD%EF%BC%89%EF%BC%9Ahttps://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#fallback-headers%EF%BF%BC4%E9%99%90%E6%B5%81%EF%BC%9Ahttps://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#the-requestratelimiter-gatewayfilter-factory%EF%BF%BC5%E8%B6%85%E6%97%B6%E6%97%B6%E9%97%B4%EF%BC%9Ahttps://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#http-timeouts-configuration%EF%BF%BC6%E9%87%8D%E8%AF%95%EF%BC%88%E4%B8%9A%E5%8A%A1%E4%BF%9D%E6%8A%A4%EF%BC%89%EF%BC%9Ahttps://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#the-retry-gatewayfilter-factory) 2. 信息脱敏：[https://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#the-removerequestheader-gatewayfilter-factory](https://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#requestheadersize-gatewayfilter-factory%EF%BF%BC2%E4%BF%A1%E6%81%AF%E8%84%B1%E6%95%8F%EF%BC%9Ahttps://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#the-removerequestheader-gatewayfilter-factory%EF%BF%BC3%E9%99%8D%E7%BA%A7%EF%BC%88%E7%86%94%E6%96%AD%EF%BC%89%EF%BC%9Ahttps://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#fallback-headers%EF%BF%BC4%E9%99%90%E6%B5%81%EF%BC%9Ahttps://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#the-requestratelimiter-gatewayfilter-factory%EF%BF%BC5%E8%B6%85%E6%97%B6%E6%97%B6%E9%97%B4%EF%BC%9Ahttps://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#http-timeouts-configuration%EF%BF%BC6%E9%87%8D%E8%AF%95%EF%BC%88%E4%B8%9A%E5%8A%A1%E4%BF%9D%E6%8A%A4%EF%BC%89%EF%BC%9Ahttps://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#the-retry-gatewayfilter-factory) 3. 降级（熔断）：[https://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#fallback-headers](https://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#requestheadersize-gatewayfilter-factory%EF%BF%BC2%E4%BF%A1%E6%81%AF%E8%84%B1%E6%95%8F%EF%BC%9Ahttps://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#the-removerequestheader-gatewayfilter-factory%EF%BF%BC3%E9%99%8D%E7%BA%A7%EF%BC%88%E7%86%94%E6%96%AD%EF%BC%89%EF%BC%9Ahttps://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#fallback-headers%EF%BF%BC4%E9%99%90%E6%B5%81%EF%BC%9Ahttps://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#the-requestratelimiter-gatewayfilter-factory%EF%BF%BC5%E8%B6%85%E6%97%B6%E6%97%B6%E9%97%B4%EF%BC%9Ahttps://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#http-timeouts-configuration%EF%BF%BC6%E9%87%8D%E8%AF%95%EF%BC%88%E4%B8%9A%E5%8A%A1%E4%BF%9D%E6%8A%A4%EF%BC%89%EF%BC%9Ahttps://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#the-retry-gatewayfilter-factory) 4. 限流：[https://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#the-requestratelimiter-gatewayfilter-factory](https://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#requestheadersize-gatewayfilter-factory%EF%BF%BC2%E4%BF%A1%E6%81%AF%E8%84%B1%E6%95%8F%EF%BC%9Ahttps://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#the-removerequestheader-gatewayfilter-factory%EF%BF%BC3%E9%99%8D%E7%BA%A7%EF%BC%88%E7%86%94%E6%96%AD%EF%BC%89%EF%BC%9Ahttps://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#fallback-headers%EF%BF%BC4%E9%99%90%E6%B5%81%EF%BC%9Ahttps://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#the-requestratelimiter-gatewayfilter-factory%EF%BF%BC5%E8%B6%85%E6%97%B6%E6%97%B6%E9%97%B4%EF%BC%9Ahttps://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#http-timeouts-configuration%EF%BF%BC6%E9%87%8D%E8%AF%95%EF%BC%88%E4%B8%9A%E5%8A%A1%E4%BF%9D%E6%8A%A4%EF%BC%89%EF%BC%9Ahttps://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#the-retry-gatewayfilter-factory) 5. 超时时间：[https://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#http-timeouts-configuration](https://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#requestheadersize-gatewayfilter-factory%EF%BF%BC2%E4%BF%A1%E6%81%AF%E8%84%B1%E6%95%8F%EF%BC%9Ahttps://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#the-removerequestheader-gatewayfilter-factory%EF%BF%BC3%E9%99%8D%E7%BA%A7%EF%BC%88%E7%86%94%E6%96%AD%EF%BC%89%EF%BC%9Ahttps://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#fallback-headers%EF%BF%BC4%E9%99%90%E6%B5%81%EF%BC%9Ahttps://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#the-requestratelimiter-gatewayfilter-factory%EF%BF%BC5%E8%B6%85%E6%97%B6%E6%97%B6%E9%97%B4%EF%BC%9Ahttps://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#http-timeouts-configuration%EF%BF%BC6%E9%87%8D%E8%AF%95%EF%BC%88%E4%B8%9A%E5%8A%A1%E4%BF%9D%E6%8A%A4%EF%BC%89%EF%BC%9Ahttps://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#the-retry-gatewayfilter-factory) 6. 重试（业务保护）： [https://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#the-retry-gatewayfilter-factory](https://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#requestheadersize-gatewayfilter-factory%EF%BF%BC2%E4%BF%A1%E6%81%AF%E8%84%B1%E6%95%8F%EF%BC%9Ahttps://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#the-removerequestheader-gatewayfilter-factory%EF%BF%BC3%E9%99%8D%E7%BA%A7%EF%BC%88%E7%86%94%E6%96%AD%EF%BC%89%EF%BC%9Ahttps://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#fallback-headers%EF%BF%BC4%E9%99%90%E6%B5%81%EF%BC%9Ahttps://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#the-requestratelimiter-gatewayfilter-factory%EF%BF%BC5%E8%B6%85%E6%97%B6%E6%97%B6%E9%97%B4%EF%BC%9Ahttps://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#http-timeouts-configuration%EF%BF%BC6%E9%87%8D%E8%AF%95%EF%BC%88%E4%B8%9A%E5%8A%A1%E4%BF%9D%E6%8A%A4%EF%BC%89%EF%BC%9Ahttps://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#the-retry-gatewayfilter-factory) ### **统一业务处理** 把一些每个项目中都要做的通用逻辑放到上层（网关），统一处理，比如本项目的次数统计 ### 统一的**访问控制** 黑白名单，比如限制 DDOS IP ### **统一日志** 统一的请求、响应信息记录 ### **统一文档** 将下游项目的文档进行聚合，在一个页面统一查看 建议用：[https://doc.xiaominfo.com/docs/middleware-sources/aggregation-introduction ](https://doc.xiaominfo.com/docs/middleware-sources/aggregation-introduction%EF%BF%BC) ## **网关的分类** 1. 全局网关（接入层网关）：作用是负载均衡、请求日志等，不和业务逻辑绑定 2. 业务网关（微服务网关）：会有一些业务逻辑，作用是将请求转发到不同的业务 / 项目 / 接口 / 服务 ## **网关实现** 1. Nginx（全局网关）、Kong 网关（API 网关，Kong)，编程成本相对高一点，还需要学新的语言 2. [Spring](https://github.com/Kong/kong%EF%BC%89%EF%BC%8C%E7%BC%96%E7%A8%8B%E6%88%90%E6%9C%AC%E7%9B%B8%E5%AF%B9%E9%AB%98%E4%B8%80%E7%82%B9%EF%BF%BC2Spring) Cloud Gateway（取代了 Zuul）性能高、可以用 Java 代码来写逻辑，适于学习 ## **Spring Cloud Gateway 用法** 路由（根据什么条件，转发请求到哪里） 断言：一组规则、条件，用来确定如何转发路由 过滤器：对请求进行一系列的处理，比如添加请求头、添加请求参数 创建项目需要安装的依赖 ![](https://cdn.hashnode.com/res/hashnode/image/upload/v1695862683921/3c1bfb22-aae1-4cae-bec5-0eba3449e11f.png align="center") **请求流程：** 1. 客户端发起请求 2. Handler Mapping：根据断言，去将请求转发到对应的路由 3. Web Handler：处理请求（一层层经过过滤器） 4. 实际调用服务 ![](https://cdn.hashnode.com/res/hashnode/image/upload/v1695860928569/f485ee39-0fb2-4f2d-9ff4-99ddb9a15385.png align="center") ### **两种配置方式** 1. 配置式（方便、规范） 1） 简化版 ```xml spring: cloud: gateway: routes: - id: after_route uri: https://example.org predicates: - Cookie=mycookie,mycookievalue ``` 1. 全称版 ```xml spring: cloud: gateway: routes: - id: after_route uri: https://example.org predicates: - name: Cookie args: name: mycookie regexp: mycookievalue ``` 2. 编程式（灵活、相对麻烦） ```java @SpringBootApplication public class DemogatewayApplication { @Bean public RouteLocator customRouteLocator(RouteLocatorBuilder builder) { return builder.routes() .route("path_route", r -> r.path("/get") .uri("http://httpbin.org")) .route("host_route", r -> r.host("*.myhost.org") .uri("http://httpbin.org")) .route("rewrite_route", r -> r.host("*.rewrite.org") .filters(f -> f.rewritePath("/foo/(?.*)", "/${segment}")) .uri("http://httpbin.org")) .route("hystrix_route", r -> r.host("*.hystrix.org") .filters(f -> f.hystrix(c -> c.setName("slowcmd"))) .uri("http://httpbin.org")) .route("hystrix_fallback_route", r -> r.host("*.hystrixfallback.org") .filters(f -> f.hystrix(c -> c.setName("slowcmd").setFallbackUri("forward:/hystrixfallback"))) .uri("http://httpbin.org")) .route("limit_route", r -> r .host("*.limited.org").and().path("/anything/**") .filters(f -> f.requestRateLimiter(c -> c.setRateLimiter(redisRateLimiter()))) .uri("http://httpbin.org")) .build(); } } ``` ### 开启日志 ```xml logging: level: org: springframework: cloud: gateway: trace ``` ### **断言** 1. After 在 xx 时间之后 场景：一般某个活动的结束、开始就需要这种`断言` 2. Before 在 xx 时间之前 3. Between 在 xx 时间之间 4. 请求类别 5. 请求头（包含 Cookie） 6. 查询参数 7. 客户端地址 8. **权重** ### **过滤器** 基本功能：对请求头、请求参数、响应头的增删改查 1. 添加请求头 2. 添加请求参数 3. 添加响应头 4. 降级 5. 限流 6. 重试 依赖 ```xml org.springframework.cloud spring-cloud-starter-circuitbreaker-reactor-resilience4j ```