前言

• 讲解spring boot中使用。spring cloud中使用（gateway、nacos中使用）。注意，只做限流讲解，同时spring boot为spring mvc框架。spring cloud使用spring webflux框架

• 基础环境 spring boot 2.4.13，sentinel 2021.1,nacos 2021.1，gateway 3.0.7

• 不提供sentinel控制台jar包，版本1.8.2。不提供nacos中心jar包，版本2.0.3。

spring boot项目限流（需要gateway等的往下翻）

• 在单独的spring boot整体项目中限流，此处我做的是代码持久化，注意是注解式。

• pom.xml文件配置

        <!-- sentinel -->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
            <version>2021.1</version>
        </dependency>

• xxx.yml配置

spring:
  cloud:
    sentinel:
      transport:
        dashboard: localhost:30010  //控制包jar包地址。是否与控制台连接开关，不做测试建议注释，会产生本地文件
        heartbeat-interval-ms: 5000  //心跳时间ms
      enabled: true //Sentinel自动化配置是否生效

• 创建自定义规则配置。注意，我这里spring boot项目是多模块，为了解耦才这么写

public abstract class CustomSentinelConfig {

    @PostConstruct
    private void config() {
        List<FlowRule> flowRules = new ArrayList<>();

        /**
         * 添加限流方式
         * 10次拒绝访问
         */
        FlowRule flowRule1 = new FlowRule();
        //资源名，资源名是限流规则的作用对象
        flowRule1.setResource("限流-10");
        //限流阈值
        flowRule1.setCount(10);
        //调用关系限流策略：直接、链路、关联
        flowRule1.setStrategy(0);
        //限流阈值类型，QPS 或线程数模式
        flowRule1.setGrade(RuleConstant.FLOW_GRADE_QPS);
        //流控效果（直接拒绝 / 慢启动模式 / 排队等待），不支持按调用关系限流，不支持线程
        flowRule1.setControlBehavior(0);
        //组装
        flowRules.add(flowRule1);

        /**
         * 添加限流方式
         * 5次等待排队
         */
        FlowRule flowRule2 = new FlowRule();
        //资源名，资源名是限流规则的作用对象
        flowRule2.setResource("限流等待-5");
        //限流阈值
        flowRule2.setCount(5);
        //调用关系限流策略：直接、链路、关联
        flowRule2.setStrategy(0);
        //限流阈值类型，QPS 或线程数模式
        flowRule2.setGrade(RuleConstant.FLOW_GRADE_QPS);
        //流控效果（直接拒绝 / 慢启动模式 / 排队等待），不支持按调用关系限流，不支持线程
        flowRule2.setControlBehavior(2);
        //超时时间设置
        flowRule2.setMaxQueueingTimeMs(60000);
        //组装
        flowRules.add(flowRule2);

        /**
         * 添加限流方式
         * 2次拒绝访问
         */
        FlowRule flowRule3 = new FlowRule();
        //资源名，资源名是限流规则的作用对象
        flowRule3.setResource("限流-2");
        //限流阈值
        flowRule3.setCount(2);
        //调用关系限流策略：直接、链路、关联
        flowRule3.setStrategy(0);
        //限流阈值类型，QPS 或线程数模式
        flowRule3.setGrade(RuleConstant.FLOW_GRADE_QPS);
        //流控效果（直接拒绝 / 慢启动模式 / 排队等待），不支持按调用关系限流，不支持线程
        flowRule3.setControlBehavior(0);
        //组装
        flowRules.add(flowRule3);

        /**
         * 添加限流方式
         * 10次等待排队
         */
        FlowRule flowRule4 = new FlowRule();
        //资源名，资源名是限流规则的作用对象
        flowRule4.setResource("限流等待-10");
        //限流阈值
        flowRule4.setCount(10);
        //调用关系限流策略：直接、链路、关联
        flowRule4.setStrategy(0);
        //限流阈值类型，QPS 或线程数模式
        flowRule4.setGrade(RuleConstant.FLOW_GRADE_QPS);
        //流控效果（直接拒绝 / 慢启动模式 / 排队等待），不支持按调用关系限流，不支持线程
        flowRule4.setControlBehavior(2);
        //超时时间设置
        flowRule4.setMaxQueueingTimeMs(60000);
        //组装
        flowRules.add(flowRule4);

        /**
         * 添加限流方式
         * 线程最多五个
         */
        FlowRule flowRule5 = new FlowRule();
        //资源名，资源名是限流规则的作用对象
        flowRule5.setResource("线程-5");
        //限流阈值
        flowRule5.setCount(5);
        //调用关系限流策略：直接、链路、关联
        flowRule5.setStrategy(0);
        //限流阈值类型，QPS 或线程数模式
        flowRule5.setGrade(RuleConstant.FLOW_GRADE_THREAD);
        //流控效果（直接拒绝 / 慢启动模式 / 排队等待），不支持按调用关系限流，不支持线程
        flowRule5.setControlBehavior(0);
        //超时时间设置
        flowRule5.setMaxQueueingTimeMs(60000);
        //组装
        flowRules.add(flowRule5);


        /**
         * 组装限流
         */
        FlowRuleManager.loadRules(currentLimitRules(flowRules));
    }

    /**
     * 限流规则配置
     *
     * @param rules
     * @return
     */
    protected abstract List<FlowRule> currentLimitRules(List<FlowRule> rules);

}

/**
 * 自定义限流规则
 *
 * @date 2021-8-9
 */
@Configuration
public class SentinelConfig extends CustomSentinelConfig {

    @Override
    protected List<FlowRule> currentLimitRules(List<FlowRule> rules) {
        return rules;  //为了解耦，继承默认配置，此处自定义增添配置
    }
}

• 在接口上使用，注意：限流可以在方法上使用，不仅仅只针对接口

    /**
     * 下载、文件
     *
     * @param url
     * @param response
     */
    @SentinelResource(value = "限流-10")  //value为对应规则
    @GetMapping("/download")
    public void download(@RequestParam String url, HttpServletResponse response) throws Exception {
        new RestBeanUtil<String, String>(null)
                .build(new OnCallBeanListener<String, String>() {
                    @Override
                    public String run(String value) throws Exception {
                        try {
                            log.info("文件下载:" + url);
                            ossService.handlerDownload(url, response);
                        } catch (Exception e) {
                            e.printStackTrace();
                            MinioUtil.downLoadFail(response, e);
                        }
                        return null;
                    }
                });
    }

• 返回规则当限流时候，需要自定义一个规则配置

/**
 * 自定义、外接哨兵异常
 *
 * @date 2021/8/9
 */
@Configuration
public class CustomBlockHandler implements BlockExceptionHandler {

    @Override
    public void handle(HttpServletRequest request, HttpServletResponse response, BlockException e) throws Exception {
        String msg = null;
        if (e instanceof FlowException) {
            //限流
            msg = JSON.toJSONString(new RestBean<>(RestCodeType.BUSY_BUSINESS));
        } else if (e instanceof DegradeException) {
            //BUSY_TOO_MANY_PEOPLE
            msg = JSON.toJSONString(new RestBean<>(RestCodeType.BUSY_UNREACHABLE));
        } else if (e instanceof ParamFlowException) {
            //热点参数限流
            msg = JSON.toJSONString(new RestBean<>(RestCodeType.BUSY_BUSINESS));
        } else if (e instanceof SystemBlockException) {
            //系统规则
            msg = JSON.toJSONString(new RestBean<>(RestCodeType.BUSY_UNREACHABLE));
        } else if (e instanceof AuthorityException) {
            //授权规则
            msg = JSON.toJSONString(new RestBean<>(RestCodeType.BUSY_UNREACHABLE));
        }
        response.setStatus(HttpStatus.NOT_ACCEPTABLE.value());
        response.setCharacterEncoding("utf-8");
        response.setHeader("Content-Type", "application/json;charset=utf-8");
        response.getWriter().write(msg);
        response.getWriter().close();
    }

}

• RestBean是自定义的restful风格实体，RestCodeType为枚举类

    /**
     * 流量限制类
     */
    BUSY_BUSINESS(70000, "当前业务繁忙，请稍后再试"),

    BUSY_UNREACHABLE(70010, "当前业务暂停，请稍后再试"),

    BUSY_TOO_MANY_PEOPLE(70020, "当前访问人数过多，请稍后再试"),

    BUSY_IP_BAN(70030, "超出接口访问次数，请稍后再试"),

spring cloud 限流注意：框架为webflux

• pom.xml文件配置

<!--gateway依赖，不能与web依赖放在一起-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-gateway</artifactId>
            <version>3.0.7</version>
        </dependency>

        <!--gateway与nacos获取微服务-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-loadbalancer</artifactId>
            <version>3.0.5</version>
        </dependency>

        <!--lombok-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.18</version>
            <scope>provided</scope>
        </dependency>

        <!-- 注册中心-->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
            <version>2021.1</version>
        </dependency>

        <!--fastjson-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.75</version>
        </dependency>

        <!--sentinel-->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
            <version>2021.1</version>
        </dependency>

        <!--sentinel-nacos-->
        <dependency>
            <groupId>com.alibaba.csp</groupId>
            <artifactId>sentinel-datasource-nacos</artifactId>
            <version>1.8.3</version>
        </dependency>

        <!--sentinel-gateway 暂时不用添加，后续讲解-->  
        <!--        <dependency>-->
        <!--            <groupId>com.alibaba.cloud</groupId>-->
        <!--            <artifactId>spring-cloud-alibaba-sentinel-gateway</artifactId>-->
        <!--            <version>2021.1</version>-->
        <!--        </dependency>-->

• xxx.yml配置

---
spring:
  application:
    name: gateway
  cloud:
    nacos:
      discovery:
        server-addr: 127.0.0.1:8848
        group: remote
        namespace: b14470b8-2099-41c1-8652-8cad015b0b53


---
#限流配置
spring:
  cloud:
    sentinel:
      transport:
        dashboard: localhost:30010
        heartbeat-interval-ms: 5000
      datasource:
        ds1:
          nacos:
            server-addr: 127.0.0.1:8848
            dataId: sentinel-service
            groupId: sentinel
            data-type: json
            rule_type: flow
            namespace: b14470b8-2099-41c1-8652-8cad015b0b53  //看是否为个人空间，否则去掉
      enabled: true //此处必须打开

---
spring:
  cloud:
    gateway:
      discovery:
        locator:
          enabled: false
          lower-case-service-id: true
      routes:   //网关的路由，测试使用，不成功去掉
        - id: oss-service
          uri: lb://oss
          predicates:
            - Path=/oss/**
            - Method=GET,POST

• 打开nacos中心，创建sentinel-service配置
  

  

  image.png

• 文件配置

resource：资源名称
limitApp：来源应用
grade：阀值类型，0---线程数，1---QPS
count：单机阀值
strategy：流控模式，0---直接，1---关联，2---链路
controlBehavior：流控效果，0---快速失败，1---warmUp，2---排队等待
clusterMode：是否集群

[
    {
       "resource": "/authentication/queryUserList",
       "limitApp":"default",
       "grade":1,
       "count":1,
       "strategy":0,
       "controlBehavior":0,
       "clusterMode":false 
    },
    {
       "resource": "/main/s",
       "limitApp":"default",
       "grade":1,
       "count":1,
       "strategy":0,
       "controlBehavior":0,
       "clusterMode":false 
    }
]

• 配置限流返回信息

@Configuration
public class SentinelHandler implements BlockRequestHandler {

    @Value("${customGateWay.sentinel.info:{\"result\":7000,\"message\":\"当前业务繁忙，请稍后再试\"}}")
    private String info;

    @Override
    public Mono<ServerResponse> handleRequest(ServerWebExchange exchange, Throwable throwable) {
        return ServerResponse.ok().contentType(MediaType.APPLICATION_JSON).body(Mono.just(info), String.class);
    }
}

• 启动项目

  
  
  

  image.png

image.png

spring 网关限流基于spring-cloud-alibaba-sentinel-gateway包

• 上面的spring cloud限流针对的是接口名称，加上下包后，将会是针对网关的限流

        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-alibaba-sentinel-gateway</artifactId>
            <version>2021.1</version>
        </dependency>

• 根据项目业务需求，看是针对单个接口限流还是某类业务限流。添加后，接口限流将会失败，二者应该是存一不兼容。
  

  

  image.png

• 修改SentinelHandler的继承类，否则无法正常回调

//import com.alibaba.csp.sentinel.adapter.spring.webflux.callback.BlockRequestHandler;
import com.alibaba.csp.sentinel.adapter.gateway.sc.callback.BlockRequestHandler;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.MediaType;
import org.springframework.web.reactive.function.server.ServerResponse;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;



/**
 * 限流、处理器
 *
 * @date 2022/4/6
 */
@Configuration
public class SentinelHandler implements BlockRequestHandler {

    @Value("${customGateWay.sentinel.info:{\"result\":7000,\"message\":\"当前业务繁忙，请稍后再试\"}}")
    private String info;

    @Override
    public Mono<ServerResponse> handleRequest(ServerWebExchange exchange, Throwable throwable) {
        return ServerResponse.ok().contentType(MediaType.APPLICATION_JSON).body(Mono.just(info), String.class);
    }
}

注意

• 不必要的文件不使用sentinel控制台时，请注释dashboard监控，否则会产生大量警告日志

      transport:
#        dashboard: localhost:30010
        heartbeat-interval-ms: 5000