spring:
  application:
    name: hello-gateway
  cloud:
    gateway:
      routes:
        - id: path_route
          uri: http://127.0.0.1:8082
          predicates:
          - Path=/hello/**

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>spring-cloud-tutorials</artifactId>
        <groupId>com.bolingcavalry</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>gateway-dynamic-route</artifactId>

    <dependencies>
        <dependency>
            <groupId>com.bolingcavalry</groupId>
            <artifactId>common</artifactId>
            <version>${project.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-gateway</artifactId>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <!-- 如果父工程不是springboot，就要用以下方式使用插件，才能生成正常的jar -->
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <mainClass>com.bolingcavalry.gateway.GatewayDynamicRouteApplication</mainClass>
                </configuration>
                <executions>
                    <execution>
                        <goals>
                            <goal>repackage</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>

package com.bolingcavalry.gateway;

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

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

package com.bolingcavalry.gateway.filter;

import lombok.Data;
import lombok.ToString;
import lombok.extern.slf4j.Slf4j;
import org.springframework.cloud.gateway.filter.GatewayFilter;
import org.springframework.cloud.gateway.filter.factory.AbstractGatewayFilterFactory;
import org.springframework.cloud.gateway.route.Route;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpMethod;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.stereotype.Component;
import org.springframework.util.MultiValueMap;
import org.springframework.web.util.UriComponentsBuilder;
import java.net.URI;
import static org.springframework.cloud.gateway.support.ServerWebExchangeUtils.GATEWAY_ROUTE_ATTR;

@Component
@Slf4j
public class BizLogicRouteGatewayFilterFactory extends AbstractGatewayFilterFactory<BizLogicRouteGatewayFilterFactory.BizLogicRouteConfig> {

    private static final String TAG_TEST_USER = "tag-test-user";

    public BizLogicRouteGatewayFilterFactory() {
        super(BizLogicRouteConfig.class);
    }

    @Override
    public GatewayFilter apply(BizLogicRouteConfig config) {

        return (exchange, chain) -> {
            // 本次的請求對象
            ServerHttpRequest request =  exchange.getRequest();

            // 調(diào)用方請求時的path
            String rawPath = request.getURI().getRawPath();

            log.info("rawPath [{}]", rawPath);

            // 請求頭
            HttpHeaders headers = request.getHeaders();

            // 請求方法
            HttpMethod httpMethod = request.getMethod();

            // 請求參數(shù)
            MultiValueMap<String, String> queryParams = request.getQueryParams();

            // 這就是定制的業(yè)務(wù)邏輯，isTestUser等于ture代表當前請求來自測試用戶，需要被轉(zhuǎn)發(fā)到測試環(huán)境
            boolean isTestUser = false;

            // 如果header中有tag-test-user這個key，并且值等于true(不區(qū)分大小寫)，
            // 就認為當前請求是測試用戶發(fā)來的
            if (headers.containsKey(TAG_TEST_USER)) {
                String tageTestUser = headers.get(TAG_TEST_USER).get(0);

                if ("true".equalsIgnoreCase(tageTestUser)) {
                    isTestUser = true;
                }
            }

            URI uri;

            if (isTestUser) {
                log.info("這是測試用戶的請求");
                // 從配置文件中得到測試環(huán)境的uri
                uri = UriComponentsBuilder.fromHttpUrl(config.getTestEnvUri() + rawPath).queryParams(queryParams).build().toUri();
            } else {
                log.info("這是普通用戶的請求");
                // 從配置文件中得到正式環(huán)境的uri
                uri = UriComponentsBuilder.fromHttpUrl(config.getProdEnvUri() + rawPath).queryParams(queryParams).build().toUri();
            }

            // 生成新的Request對象，該對象放棄了常規(guī)路由配置中的spring.cloud.gateway.routes.uri字段
            ServerHttpRequest serverHttpRequest = request.mutate().uri(uri).method(httpMethod).headers(httpHeaders -> httpHeaders = httpHeaders).build();

            // 取出當前的route對象
            Route route = exchange.getAttribute(GATEWAY_ROUTE_ATTR);
            //從新設(shè)置Route地址
            Route newRoute =
                    Route.async().asyncPredicate(route.getPredicate()).filters(route.getFilters()).id(route.getId())
                            .order(route.getOrder()).uri(uri).build();
            // 放回exchange中
            exchange.getAttributes().put(GATEWAY_ROUTE_ATTR,newRoute);

            // 鏈式處理，交給下一個過濾器
            return chain.filter(exchange.mutate().request(serverHttpRequest).build());
        };
    }

    /**
     * 這是過濾器的配置類，配置信息會保存在此處
     */
    @Data
    @ToString
    public static class BizLogicRouteConfig {
        // 生產(chǎn)環(huán)境的服務(wù)地址
        private String prodEnvUri;

        // 測試環(huán)境的服務(wù)地址
        private String testEnvUri;
    }
}

server:
  #服務(wù)端口
  port: 8086
spring:
  application:
    name: gateway-dynamic-route
  cloud:
    gateway:
      routes:
        - id: path_route
          uri: http://0.0.0.0:8082
          predicates:
          - Path=/hello/**
          filters:
            - name: BizLogicRoute
              args:
                prodEnvUri: http://127.0.0.1:8082
                testEnvUri: http://127.0.0.1:8087

package com.bolingcavalry.provider.controller;

import com.bolingcavalry.common.Constants;
import org.springframework.web.bind.annotation.*;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Map;

@RestController
@RequestMapping("/hello")
public class Hello {

    private String dateStr(){
        return new SimpleDateFormat("yyyy-MM-dd hh:mm:ss").format(new Date());
    }

    /**
     * 返回字符串類型
     * @return
     */
    @GetMapping("/str")
    public String helloStr() {
        return Constants.HELLO_PREFIX + ", " + dateStr() + " (from test enviroment)";
    }
}