Spring Cloud Gateway--用GlobalFilter实现动态路由--实例/方案

旧城等待， 2023-09-29 12:30 12阅读 0赞

原文网址：[Spring Cloud Gateway--用GlobalFilter实现动态路由--实例/方案\_IT利刃出鞘的博客-CSDN博客][Spring Cloud Gateway--_GlobalFilter_--_IT_-CSDN]

## 简介 ##

本文用示例介绍Spring Cloud Gateway的动态路由（强制路由）的方案。

## **为什么需要动态路由** ##

**场景1：开发环境：提高调试效率**

在开发软件（例如Idea）上打断点调试是最快的调试方法。如果是与前端联调，前端一般将请求地址设置为网关，这样会负载均衡到不同的机器上，不能指定到自己的电脑。

如果有了动态路由，那么可以指定某个url直接路由到自己电脑。

**场景2：线上环境：可以快速将请求切到某个服务器**

如果没有动态路由，代码上线时如果出了问题，需要回滚代码，重新部署，很慢。

如果有了动态路由，代码上线时，只更新部分实例，然后将流量切过去，如果有问题，立马切到其他未更新的实例即可。

## 实例 ##

### gateway项目 ###

#### **自定义GlobalFilter（核心）** ####

package com.knife.dynamic;
    
    import lombok.extern.slf4j.Slf4j;
    import org.springframework.cloud.gateway.filter.GatewayFilterChain;
    import org.springframework.cloud.gateway.filter.GlobalFilter;
    import org.springframework.cloud.gateway.support.ServerWebExchangeUtils;
    import org.springframework.core.Ordered;
    import org.springframework.http.server.reactive.ServerHttpRequest;
    import org.springframework.stereotype.Component;
    import org.springframework.web.server.ServerWebExchange;
    import org.springframework.web.util.UriComponentsBuilder;
    import reactor.core.publisher.Mono;
    
    import java.net.URI;
    
    /**
     * 动态路由
     */
    @Slf4j
    @Component
    public class Router4jClientFilter implements GlobalFilter, Ordered {
        @Override
        public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
            ServerHttpRequest originalRequest = exchange.getRequest();
    
            // 可获得所有请求参数
            // Map<String, String> cachedRequestBody = exchange
            // .getAttribute(ServerWebExchangeUtils.CACHED_REQUEST_BODY_ATTR);
    
            //获取域名+端口后的path
            String rawPath = originalRequest.getURI().getRawPath();
    
            // todo 从redis中取出所有url，然后用rawPath去匹配
    
            String host = "localhost";
            int port = 9012;
    
            URI originUri = exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR);
    
            URI newUri = UriComponentsBuilder.fromUri(originUri)
                    .host(host)
                    .port(port)
                    .build()
                    .toUri();
    
            //重新封装request对象
            ServerHttpRequest newRequest = originalRequest.mutate().uri(newUri).build();
    
            // NettyRoutingFilter 最终从GATEWAY_REQUEST_URL_ATTR 取出uri对象进行http请求
            // 所以这里要将新的对象覆盖进去
            exchange.getAttributes().put(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR, newUri);
    
            return chain.filter(exchange.mutate().request(newRequest).build());
    
            // 也可以加回调方法
            // return chain.filter(exchange.mutate().request(newRequest).build())
            //         .then(Mono.fromRunnable(() -> {
            //             //请求完成回调方法 可以在此完成计算请求耗时等操作
            //         }));
        }
    
        /**
         * 这里不能用@Order，必须实现Ordered接口
         * 值必须大于10150。原因：Gateway有自己的过滤器，两个比较重要的如下：
         *      RouteToRequestUrlFilter：将根据Route将网关请求转为真实的请求。order = 10000
         *      ReactiveLoadBalancerClientFilter：负载均衡。order = 10150
         */
        @Override
        public int getOrder() {
            return 15000;
        }
    }

#### 配置文件 ####

server:
      port: 6001
    
    spring:
      application:
        name: gateway
      cloud:
        gateway:
          discovery:
            locator:
              # 解析微服务名称为主机名和端口，实现动态路由
              enabled: true
              # 服务名使用小写
              lower-case-service-id: true
        nacos:
          discovery:
            server-addr: localhost:8848
    
    # 配置Gateway日志等级，输出转发细节信息
    logging:
      level:
        org.springframework.cloud.gateway: debug

#### 依赖 ####

<?xml version="1.0" encoding="UTF-8"?>
    <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
        <modelVersion>4.0.0</modelVersion>
        <parent>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            
            <version>2.4.13</version>
            <relativePath/> 
        </parent>
        <groupId>com.knife</groupId>
        <artifactId>gateway</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <name>gateway</name>
        <description>Demo project for Spring Boot</description>
    
        <properties>
            <java.version>1.8</java.version>
        </properties>
    
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter</artifactId>
            </dependency>
    
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-gateway</artifactId>
            </dependency>
    
            <dependency>
                <groupId>com.alibaba.cloud</groupId>
                <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
            </dependency>
    
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-loadbalancer</artifactId>
            </dependency>
    
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <version>1.18.24</version>
                <scope>provided</scope>
            </dependency>
    
            <dependency>
                <groupId>com.knife</groupId>
                <artifactId>router4j-client</artifactId>
                <version>0.0.1-SNAPSHOT</version>
            </dependency>
    
        </dependencies>
    
        <dependencyManagement>
            <dependencies>
                <dependency>
                    <groupId>org.springframework.cloud</groupId>
                    <artifactId>spring-cloud-dependencies</artifactId>
                    <version>2020.0.1</version>
                    <type>pom</type>
                    <scope>import</scope>
                </dependency>
    
                <dependency>
                    <groupId>com.alibaba.cloud</groupId>
                    <artifactId>spring-cloud-alibaba-dependencies</artifactId>
                    <version>2021.1</version>
                    <type>pom</type>
                    <scope>import</scope>
                </dependency>
            </dependencies>
        </dependencyManagement>
    
        <build>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                    <version>2.4.13</version>
                </plugin>
            </plugins>
        </build>
    
    </project>

### nacos项目 ###

nacos直接从官方下载，然后运行即可。

见：[Nacos 快速开始][Nacos]

### 业务项目 ###

**Controller**

package com.knife.order.controller;
    
    import com.knife.common.entity.Result;
    import com.knife.order.entity.Order;
    import lombok.extern.slf4j.Slf4j;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.PostMapping;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    /**
     * http://localhost:9011/order/create/?userId=1&productId=1&count=10&money=100
     */
    @Slf4j
    @RestController
    @RequestMapping("order")
    public class OrderController {
        // 正常流程
        @PostMapping("create")
        public Result create(Order order) {
            log.info("订单服务：创建订单：{}", order);
    
            return new Result().message("创建订单成功");
        }
    
    }

#### **配置文件** ####

**bootstrap.yml**

spring:
      application:
        name: order
      cloud:
        nacos:
          config:
            server-addr: 127.0.0.1:8848

**application.yml**

server:
      port: 9012
    
    spring:
      application:
        name: order
      cloud:
        nacos:
          discovery:
            server-addr: 127.0.0.1:8848

#### **依赖** ####

<?xml version="1.0" encoding="UTF-8"?>
    <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
        <modelVersion>4.0.0</modelVersion>
        <parent>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            <version>2.4.13</version>
        </parent>
        <modelVersion>4.0.0</modelVersion>
        <packaging>pom</packaging>
        <groupId>com.knife</groupId>
        <artifactId>parent</artifactId>
        <version>0.0.1-SNAPSHOT</version>
    
        <properties>
            <java.version>1.8</java.version>
        </properties>
    
        <dependencyManagement>
            <dependencies>
                <dependency>
                    <groupId>org.springframework.cloud</groupId>
                    <artifactId>spring-cloud-dependencies</artifactId>
                    <version>2020.0.1</version>
                    <type>pom</type>
                    <scope>import</scope>
                </dependency>
    
                <dependency>
                    <groupId>com.alibaba.cloud</groupId>
                    <artifactId>spring-cloud-alibaba-dependencies</artifactId>
                    <version>2021.1</version>
                    <type>pom</type>
                    <scope>import</scope>
                </dependency>
            </dependencies>
        </dependencyManagement>
    
        <properties>
            <java.version>1.8</java.version>
        </properties>
    
        <dependencyManagement>
    
    
            <dependencies>
                <dependency>
                    <groupId>com.alibaba.cloud</groupId>
                    <artifactId>spring-cloud-alibaba-dependencies</artifactId>
                    <version>2021.1</version>
                    <type>pom</type>
                    <scope>import</scope>
                </dependency>
            </dependencies>
        </dependencyManagement>
    
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
    
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-openfeign</artifactId>
            </dependency>
    
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <version>1.18.24</version>
                <scope>provided</scope>
            </dependency>
    
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <scope>test</scope>
            </dependency>
    
            <dependency>
                <groupId>com.alibaba.cloud</groupId>
                <artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
            </dependency>
    
            <dependency>
                <groupId>com.alibaba.cloud</groupId>
                <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
                <exclusions>
                    <exclusion>
                        <groupId> springframework.cloud</groupId>
                        <artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
                    </exclusion>
                </exclusions>
            </dependency>
    
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-loadbalancer</artifactId>
            </dependency>
    
            <dependency>
                <groupId>com.knife</groupId>
                <artifactId>common</artifactId>
                <version>0.0.1-SNAPSHOT</version>
            </dependency>
    
        </dependencies>
    
        <build>
            <plugins>
    
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                    <version>2.4.13</version>
                </plugin>
    
            </plugins>
        </build>
    
    </project>

#### 测试 ####

#### 启动程序 ####

**1.启动nacos服务**

执行：startup.cmd -m standalone

**2.启动gateway服务**

**3.启动两个业务服务（order）**

分别以不同的端口号启动。

先以上边的配置启动，再修改application.yml里的端口号，然后启动。修改后的为：

server:
      port: 9013
    
    spring:
      application:
        name: order
      cloud:
        nacos:
          discovery:
            server-addr: 127.0.0.1:8848

Idea同一个服务启动两个实例的方法见：[Intellij IDEA--项目设置--导入项目/导入包/乱码/JDK版本\_IT利刃出鞘的博客-CSDN博客][Intellij IDEA--_--_JDK_IT_-CSDN]

搜索关键字“同一服务启动多个实例”

#### 测试 ####

POST方式请求：[http://localhost:6001/order/order/create/?userId=1&productId=1&count=10&money=100][http_localhost_6001_order_order_create_userId_1_productId_1_count_10_money_100]

请求10次，结果：请求全部到了指定的服务：9012端口

9012端口的服务：

![037511e6d6da4766a69bf2341d08a57d.png][]

9013端口的服务：

![cffd99e2cca14229bc8ec67c63b75545.png][]

[Spring Cloud Gateway--_GlobalFilter_--_IT_-CSDN]: https://knife.blog.csdn.net/article/details/124485989
[Nacos]: https://nacos.io/zh-cn/docs/quick-start.html
[Intellij IDEA--_--_JDK_IT_-CSDN]: https://knife.blog.csdn.net/article/details/104720249
[http_localhost_6001_order_order_create_userId_1_productId_1_count_10_money_100]: http://localhost:6001/order/order/create/?userId=1&productId=1&count=10&money=100
[037511e6d6da4766a69bf2341d08a57d.png]: https://img-blog.csdnimg.cn/037511e6d6da4766a69bf2341d08a57d.png
[cffd99e2cca14229bc8ec67c63b75545.png]: https://img-blog.csdnimg.cn/cffd99e2cca14229bc8ec67c63b75545.png