SA实战 ·《SpringCloud Alibaba实战》第13章-服务网关：项目整合SpringCloud Gateway网关 下

<dependencies>
    <dependency>
        <groupId>com.alibaba.cloud</groupId>
        <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
    </dependency>
    <dependency>
        <groupId>com.alibaba.cloud</groupId>
        <artifactId>spring-cloud-alibaba-sentinel-gateway</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>com.alibaba.csp</groupId>
        <artifactId>sentinel-spring-cloud-gateway-adapter</artifactId>
    </dependency>
</dependencies>

/**
 * @author binghe (公众号：冰河技术)
 * @version 1.0.0
 * @description 网关配置类
 */
@Configuration
public class GatewayConfig {
    private final List<ViewResolver> viewResolvers;
    private final ServerCodecConfigurer serverCodecConfigurer;
    @Value("${spring.cloud.gateway.discovery.locator.route-id-prefix}")
    private String routeIdPrefix;
    public GatewayConfig(ObjectProvider<List<ViewResolver>> viewResolversProvider,
                                ServerCodecConfigurer serverCodecConfigurer) {
        this.viewResolvers = viewResolversProvider.getIfAvailable(Collections::emptyList);
        this.serverCodecConfigurer = serverCodecConfigurer;
    }
    /**
     * 初始化一个限流的过滤器
     */
    @Bean
    @Order(Ordered.HIGHEST_PRECEDENCE)
    public GlobalFilter sentinelGatewayFilter() {
        return new SentinelGatewayFilter();
    }
    @PostConstruct
    public void init() {
       this.initGatewayRules();
       this.initBlockHandlers();
    }
    /**
     * 配置初始化的限流参数
     */
    private void initGatewayRules() {
        Set<GatewayFlowRule> rules = new HashSet<>();
        /**
         * Sentinel整合SpringCloud Gateway使用的API类型为Route ID类型，也就是基于route维度时，
         * 由于Sentinel为SpringCloud Gateway网关生成的API名称规则如下：
         * 生成的规则为：${spring.cloud.gateway.discovery.locator.route-id-prefix}后面直接加上目标微服务的名称，如下所示。
         * ${spring.cloud.gateway.discovery.locator.route-id-prefix}目标微服务的名称
         * 其中，${spring.cloud.gateway.discovery.locator.route-id-prefix}是在yml文件中配置的访问前缀
         *
         * 为了让通过服务网关访问目标微服务链接后，请求链路中生成的API名称与流控规则中生成的API名称一致，以达到启动项目即可实现访问链接的限流效果，
         * 而无需登录Setinel管理界面手动配置限流规则，可以将
         * resource参数设置为${spring.cloud.gateway.discovery.locator.route-id-prefix}目标微服务的名称
         *
         * 当然，如果不按照上述配置，也可以在项目启动后，通过服务网关访问目标微服务链接后，在Sentinel管理界面的请求链路中找到对应的API名称所代表的请求链路，
         * 然后手动配置限流规则。
         **/
//        //用户微服务网关
//        rules.add(this.getGatewayFlowRule("user-gateway"));
//        //商品微服务网关
//        rules.add(this.getGatewayFlowRule("product-gateway"));
//        //订单微服务网关
//        rules.add(this.getGatewayFlowRule("order-gateway"));
        //用户微服务网关
        rules.add(this.getGatewayFlowRule(getResource("server-user")));
        //商品微服务网关
        rules.add(this.getGatewayFlowRule(getResource("server-product")));
        //订单微服务网关
        rules.add(this.getGatewayFlowRule(getResource("server-order")));
        //加载规则
        GatewayRuleManager.loadRules(rules);
    }
    private String getResource(String targetServiceName){
        if (routeIdPrefix == null){
            routeIdPrefix = "";
        }
        return routeIdPrefix.concat(targetServiceName);
    }
    private GatewayFlowRule getGatewayFlowRule(String resource){
        //传入资源名称生成GatewayFlowRule
        GatewayFlowRule gatewayFlowRule = new GatewayFlowRule(resource);
        //限流阈值
        gatewayFlowRule.setCount(1);
        //统计的时间窗口，单位为
        gatewayFlowRule.setIntervalSec(1);
        return gatewayFlowRule;
    }
    /**
     * 配置限流的异常处理器
     */
    @Bean
    @Order(Ordered.HIGHEST_PRECEDENCE)
    public SentinelGatewayBlockExceptionHandler sentinelGatewayBlockExceptionHandler() {
        return new SentinelGatewayBlockExceptionHandler(viewResolvers, serverCodecConfigurer);
    }
    /**
     * 自定义限流异常页面
     */
    private void initBlockHandlers() {
        BlockRequestHandler blockRequestHandler = new BlockRequestHandler() {
            @Override
            public Mono<ServerResponse> handleRequest(ServerWebExchange serverWebExchange, Throwable throwable) {
                Map map = new HashMap<>();
                map.put("code", 1001);
                map.put("codeMsg", "接口被限流了");
                return ServerResponse.status(HttpStatus.OK).
                        contentType(MediaType.APPLICATION_JSON_UTF8).
                        body(BodyInserters.fromObject(map));
            }
        };
        GatewayCallbackManager.setBlockHandler(blockRequestHandler);
    }
}

private void initCustomizedApis() {
    Set<ApiDefinition> definitions = new HashSet<>();
    ApiDefinition api1 = new ApiDefinition("user_api1")
        .setPredicateItems(new HashSet<ApiPredicateItem>() {{
            // 以/server-user/user/api1 开头的请求
            add(new ApiPathPredicateItem().setPattern("/server-user/user/api1/**").
                setMatchStrategy(SentinelGatewayConstants.URL_MATCH_STRATEGY_PREFIX));
        }});
    ApiDefinition api2 = new ApiDefinition("user_api2")
        .setPredicateItems(new HashSet<ApiPredicateItem>() {{
            // 以/server-user/user/api2/demo1 完成的url路径匹配
            add(new ApiPathPredicateItem().setPattern("/server-user/user/api2/demo1"));
        }});
    definitions.add(api1);
    definitions.add(api2);
    GatewayApiDefinitionManager.loadApiDefinitions(definitions);
}