GateWay实现新增服务不用重启网关

GateWay网关

实现目标： 通过代码写路由策略，实现新增服务的时候，不用重启网关

核心点： 从Eureka获取服务的注册信息

实现过程如下： 自定义一个过滤器

import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.cloud.client.discovery.DiscoveryClient;
import org.springframework.cloud.gateway.filter.FilterDefinition;
import org.springframework.cloud.gateway.handler.predicate.PredicateDefinition;
import org.springframework.cloud.gateway.route.RouteDefinition;
import org.springframework.cloud.gateway.route.RouteDefinitionLocator;
import org.springframework.stereotype.Component;
import reactor.core.publisher.Flux;
import java.net.URI;
import java.util.*;
/**
 * @author ma
 * @date 2022/5/23
 */
@Component
@Slf4j
public class MyRouteDefinitionLocator implements RouteDefinitionLocator {

    @Autowired
    private DiscoveryClient discoveryClient;

    @Value("${spring.application.name}")
    private String gatewayName;

    @Override
    public Flux<RouteDefinition> getRouteDefinitions() {
        // 服务发现
        List<String> serviceList = discoveryClient.getServices();
        // 只有网关服务，直接返回
        if (serviceList.size() < 2){
            return Flux.empty();
        }
        // 服务的个数
        int serviceNum = serviceList.size();
        if (serviceList.contains(gatewayName)){
            // 排除网关服务
            serviceNum--;
        }
        RouteDefinition[] routeDefinitions = new RouteDefinition[serviceNum];
        int count = 0;
        for (String service : serviceList) {
            if (service.equalsIgnoreCase(gatewayName)){
                continue;
            }
            RouteDefinition definition = new RouteDefinition();
            definition.setId(service);
            // 负载均衡
            definition.setUri(URI.create("lb://"+service));
            // 根据微服务名，进行路径匹配
            definition.setPredicates(Collections.singletonList(new PredicateDefinition("Path=/"+service+"/**")));
            // 去掉微服务名
            List<FilterDefinition> filterDefinitionList = new ArrayList<>();
            filterDefinitionList.add(new FilterDefinition("StripPrefix=1"));
            definition.setFilters(filterDefinitionList);
            routeDefinitions[count++] = definition;
        }
        return Flux.just(routeDefinitions);
    }
}

通过以上步骤，我们在新增服务的时候，会从eureka自动拉取服务信息，从而实现不用重启网关就能新增服务