spring cloud java 2、SpringCloud之Gateway断言Predicate&GatewayFilterFactory源码解析

接口RouteLocator：实现类包括CachingRouteLocator、CompositeRouteLocator、RouteDefinitionRouteLocator。

接口RouteDefinitionLocator：CacheRouteDefinitionLocator、CompositeRouteDefinitionLocator、InMemoryRouteDefinitionRepository、PropertiesRouteDefinitionLocator、接口RouteDefinitionLocatorRepository、DiscoveryClientRouteDefinitionLocator。

接口RoutePredicateFactory：默认生成14种路由策略。PathRoutePredicateFactory、HeaderRoutePredicateFactory等。

接口Predicate：

1、GatewayAutoConfiguration

初始化13种路由策略、30种GatewayFilter、RouteDefinitionRouteLocator。

2、RouteDefinitionRouteLocator

public class RouteDefinitionRouteLocator

implements RouteLocator, BeanFactoryAware, ApplicationEventPublisherAware {

private final Map predicates = new LinkedHashMap<>();

private final Map gatewayFilterFactories = new HashMap<>();

public RouteDefinitionRouteLocator(RouteDefinitionLocator routeDefinitionLocator,

List predicates,List gatewayFilterFactories,

GatewayProperties gatewayProperties,ConfigurationService configurationService) {

// CompositeRouteDefinitionLocator

this.routeDefinitionLocator = routeDefinitionLocator;

this.configurationService = configurationService;

//13种路由策略

initFactories(predicates);

// 30种GatewayFilter

gatewayFilterFactories.forEach(

// GatewayFilterFactory factory.name()：获取实现类基于接口的前缀

factory -> this.gatewayFilterFactories.put(factory.name(), factory));

this.gatewayProperties = gatewayProperties;

}

}

private void initFactories(List predicates) {

predicates.forEach(factory -> {

String key = factory.name();//获取实现类基于接口的前缀

this.predicates.put(key, factory);

});

}

匹配规则与其对应的实体对象建立映射关系。

RoutePredicateFactory的全部实现类名是在其接口RoutePredicateFactory增加了“策略”前缀。比如PathRoutePredicateFactory表明请求基于“前缀Path”路径的匹配规则。HostRoutePredicateFactory表明请求基于“前缀host”host匹配指定值等。

private Route convertToRoute(RouteDefinition routeDefinition) {

AsyncPredicate predicate = combinePredicates(routeDefinition);

List gatewayFilters = getFilters(routeDefinition);

return Route.async(routeDefinition).asyncPredicate(predicate)

.replaceFilters(gatewayFilters).build();

}

根据配置获取AsyncPredicate。处理当前Routes下的过滤器。

备注：GatewayProperties中规定routes选项可以配置多个不同目标服务的路由Route。convertToRoute只是处理其中某个Route对应的RouteDefinition。

private AsyncPredicate combinePredicates(

RouteDefinition routeDefinition) {

List predicates = routeDefinition.getPredicates();

AsyncPredicate predicate = lookup(routeDefinition,

predicates.get(0));

for (PredicateDefinition andPredicate : predicates.subList(1,

predicates.size())) {

AsyncPredicate found = lookup(routeDefinition,

andPredicate);

predicate = predicate.and(found);

}

return predicate;

}

private AsyncPredicate lookup(RouteDefinition route,

PredicateDefinition predicate) {

// 根据配置文件从RouteDefinitionRouteLocator属性集合中获取对应的Predicate

RoutePredicateFactory