private static void initFlowQpsRule() {
    List<FlowRule> rules = new ArrayList<>();
    FlowRule rule1 = new FlowRule();
    rule1.setResource(resource);
    // Set max qps to 20
    rule1.setCount(20);
    rule1.setGrade(RuleConstant.FLOW_GRADE_QPS);
    rule1.setLimitApp("default");
    rules.add(rule1);
    FlowRuleManager.loadRules(rules);
}

private static void initDegradeRule() {
    List<DegradeRule> rules = new ArrayList<>();
    DegradeRule rule = new DegradeRule(resource);
       .setGrade(CircuitBreakerStrategy.ERROR_RATIO.getType());
       .setCount(0.7); // Threshold is 70% error ratio
       .setMinRequestAmount(100)
       .setStatIntervalMs(30000) // 30s
       .setTimeWindow(10);
    rules.add(rule);
    DegradeRuleManager.loadRules(rules);
}

private void initSystemProtectionRule() {
  List<SystemRule> rules = new ArrayList<>();
  SystemRule rule = new SystemRule();
  rule.setHighestSystemLoad(10);
  rules.add(rule);
  SystemRuleManager.loadRules(rules);
}

<dependency> <groupId>com.alibaba.csp</groupId> <artifactId>sentinel-parameter-flow-control</artifactId> <version>x.y.z</version> </dependency>

// paramA in index 0, paramB in index 1.
// 若需要配置例外项或者使用集群维度流控，则传入的参数只支持基本类型。
SphU.entry(resourceName, EntryType.IN, 1, paramA, paramB);

public static void doWithSentinel(String resource, Object... params) {
    Entry entry = null;
    try {
        entry = SphU.entry(resource, EntryType.IN, 1, params);
        // 业务逻辑
    } catch (BlockException e) {
        // 被限流
        throw new RuntimeException("访问被限流：" + resource);
    } finally {
        if (entry != null) {
            entry.exit(1, params);
        }
    }
}

@SentinelResource("myMethod")
public Result doSomething(String uid, int type) {
  // some logic here...
}

ParamFlowRule rule = new ParamFlowRule(resourceName)
   .setParamIdx(0)
   .setCount(5);
// 针对 int 类型的参数 PARAM_B，单独设置限流 QPS 阈值为 10，而不是全局的阈值 5.
ParamFlowItem item = new ParamFlowItem().setObject(String.valueOf(PARAM_B))
   .setClassType(int.class.getName())
   .setCount(10);
rule.setParamFlowItemList(Collections.singletonList(item));
ParamFlowRuleManager.loadRules(Collections.singletonList(rule));

其中，type=flow 以 JSON 格式返回现有的限流规则，degrade 返回现有生效的降级规则列表，system 则返回系统保护规则。

[
    {
        "clusterConfig": {
            "acquireRefuseStrategy": 0,
            "clientOfflineTime": 2000,
            "fallbackToLocalWhenFail": true,
            "resourceTimeout": 2000,
            "resourceTimeoutStrategy": 0,
            "sampleCount": 10,
            "strategy": 0,
            "thresholdType": 0,
            "windowIntervalMs": 1000
        },
        "clusterMode": false,
        "controlBehavior": 0,
        "count": 1,
        "grade": 1,
        "limitApp": "default",
        "maxQueueingTimeMs": 500,
        "resource": "/hello/{name}",
        "strategy": 0,
        "warmUpPeriodSec": 10
    }
]

import com.alibaba.csp.sentinel.datasource.FileRefreshableDataSource;
import com.alibaba.csp.sentinel.datasource.FileWritableDataSource;
import com.alibaba.csp.sentinel.datasource.ReadableDataSource;
import com.alibaba.csp.sentinel.datasource.WritableDataSource;
import com.alibaba.csp.sentinel.init.InitFunc;
import com.alibaba.csp.sentinel.slots.block.flow.FlowRule;
import com.alibaba.csp.sentinel.slots.block.flow.FlowRuleManager;
import com.alibaba.csp.sentinel.transport.util.WritableDataSourceRegistry;
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.TypeReference;
import java.util.List;

/**
 * Sentinel 规则文件持久化
 * 控制台推送规则 → 内存 → 自动写入本地文件
 */
public class FileDataSourceInit implements InitFunc {

    @Override
    public void init() throws Exception {
        // 规则文件存放路径（可修改）
        String flowRulePath = "/usr/local/sentinel/flow-rule.json";

        // 可读数据源：启动时从文件加载规则
        ReadableDataSource<String, List<FlowRule>> ds = new FileRefreshableDataSource<>(
            flowRulePath, 
            source -> JSON.parseObject(source, new TypeReference<List<FlowRule>>() {})
        );

        // 注册到流量规则管理器
        FlowRuleManager.register2Property(ds.getProperty());

        // 可写数据源：控制台推送规则时自动写入文件
        WritableDataSource<List<FlowRule>> wds = new FileWritableDataSource<>(
            flowRulePath, 
            this::encodeJson
        );

        // 注册写入器
        WritableDataSourceRegistry.registerFlowDataSource(wds);
    }

    /**
     * 对象转JSON
     */
    private <T> String encodeJson(T t) {
        return JSON.toJSONString(t, true);
    }
}

#安装docker环境
[root@ubuntu2404 ~]#apt update && apt -y install docker.io 

#拉取镜像v1.8.8
[root@ubuntu2404 ~]#docker pull bladex/sentinel-dashboard
[root@ubuntu2404 ~]#docker pull registry.cn-beijing.aliyuncs.com/wangxiaochun/sentinel-dashboard:1.8.8

[root@ubuntu2404 ~]#docker images 
REPOSITORY                         TAG         IMAGE ID       CREATED        SIZE
bladex/sentinel-dashboard          latest      aa398704ebd3   3 years ago    147MB

#启动Sentinel-dashboard（版本不同端口不同）
# 1.8.8 端口：8080
[root@ubuntu2404 ~]#docker run --name sentinel -d -p 8080:8080 -p 8719:8719 registry.cn-beijing.aliyuncs.com/wangxiaochun/sentinel-dashboard:1.8.8

# 1.8.9 + bladex 镜像端口：8858
[root@ubuntu2404 ~]#docker run --name sentinel -d -p 8080:8858 -p 8719:8719 registry.cn-beijing.aliyuncs.com/wangxiaochun/sentinel-dashboard:1.8.9
[root@ubuntu2404 ~]#docker run --name sentinel -d -p 8080:8858 -p 8719:8719 bladex/sentinel-dashboard

#确认启动
[root@ubuntu2404 ~]#docker ps 
CONTAINER ID   IMAGE                          COMMAND                  CREATED         STATUS         PORTS                                                                                               NAMES
7e5270b7718d   bladex/sentinel-dashboard      "java -Djava.securit…"   2 seconds ago   Up 2 seconds   0.0.0.0:8719->8719/tcp, :::8719->8719/tcp, 0.0.0.0:8080->8858/tcp, :::8080->8858/tcp                   sentinel

#登录Sentinel,默认用户和密码都是sentinel
http://sentinel.wang.org:8080/

#安装工具，支持17，21
[root@ubuntu2404 ~]#apt update && apt -y install openjdk-21-jdk maven
[root@ubuntu2404 ~]#apt update && apt -y install openjdk-17-jdk maven

#确认版本
[root@ubuntu2404 ~]#mvn -v
Apache Maven 3.6.3
Maven home: /usr/share/maven
Java version: 17.0.9, vendor: Private Build, runtime: /usr/lib/jvm/java-17-openjdk-amd64
Default locale: en_US, platform encoding: UTF-8
OS name: "linux", version: "5.15.0-67-generic", arch: "amd64", family: "unix"

#主机解析
[root@ubuntu2404 ~]#cat /etc/hosts
10.0.0.100 sentinel.wang.org 
10.0.0.101 ubuntu2204.wang.org

#配置应用
[root@ubuntu2404 sentinel-sample]#cat src/main/resources/application.yml 
spring:
  application:
    name: sentinel-sample
  cloud:
    sentinel:
      eager: true
      transport:
        port: 8719
        dashboard: sentinel.wang.org:8080

#编译
[root@ubuntu2404 sentinel-sample]#mvn clean package -Dmaven.test.skip=true
[INFO] Replacing main artifact with repackaged archive
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------

#运行
[root@ubuntu2404 sentinel-sample]#java -version
openjdk version "17.0.9" 2023-10-17

#方法1：启动默认端口8080
[root@ubuntu2404 sentinel-sample]#java -jar target/sentinel-sample-0.0.1-SNAPSHOT.jar

#方法2：指定端口
[root@ubuntu2404 ~]#java -jar target/sentinel-sample-0.0.1-SNAPSHOT.jar --server.port=8888

#方法3：临时指定sentinel地址
[root@ubuntu2404 sentinel-sample]#java -Dspring.cloud.sentinel.transport.dashboard=10.0.0.100:8080 -jar target/sentinel-sample-0.0.1-SNAPSHOT.jar

#测试访问应用
http://10.0.0.101:8080/hello/wang

#https://sentinelguard.io/zh-cn/docs/flow-control.html
[root@ubuntu2404 ~]#curl http://sentinel.wang.org:8719/cnode?id=sentinel-sample
idx id                                 thread   pass     blocked   success   total   aRt   1m-pass   1mblock   1m-all   exception  
2   /app/sentinel-sample/machines.json 0         0.0       0.0       0.0        0.0      0.0   0         0     
     0        0.0  
#其中：
thread： 代表当前处理该资源的线程数；
pass： 代表一秒内到来到的请求；
blocked： 代表一秒内被流量控制的请求数量；
success： 代表一秒内成功处理完的请求；
total： 代表到一秒内到来的请求以及被阻止的请求总和；
RT： 代表一秒内该资源的平均响应时间；
1m-pass： 则是一分钟内到来的请求；
1m-block： 则是一分钟内被阻止的请求；
1m-all： 则是一分钟内到来的请求和被阻止的请求的总和；
exception： 则是一秒内业务本身异常的总和。

#如果和sentinel安装在同一台主机,可以省略安装工具
[root@ubuntu2404 ~]#apt update && apt -y install docker.io 

#拉取镜像
[root@ubuntu2404 ~]#docker pull registry.cn-beijing.aliyuncs.com/wangxiaochun/nacos-server:v2.4.3-slim
[root@ubuntu2404 ~]#docker pull registry.cn-beijing.aliyuncs.com/wangxiaochun/nacos-server:v2.2.3-slim
[root@ubuntu2404 ~]#docker pull nacos/nacos-server:v2.2.3-slim

[root@ubuntu2404 ~]#docker images 
REPOSITORY                             TAG           IMAGE ID       CREATED        SIZE
nacos/nacos-server                     v2.2.3-slim   2266763b639b   6 months ago   383MB

#启动nacos
[root@ubuntu2404 ~]#docker run --name nacos -e MODE=standalone -p 8848:8848 -p 9848:9848 -d registry.cn-beijing.aliyuncs.com/wangxiaochun/nacos-server:v2.4.3-slim
[root@ubuntu2404 ~]#docker run --name nacos -e MODE=standalone -p 8848:8848 -p 9848:9848 -d registry.cn-beijing.aliyuncs.com/wangxiaochun/nacos-server:v2.2.3-slim
[root@ubuntu2404 ~]#docker run --name nacos -e MODE=standalone -p 8848:8848 -p 9848:9848 -d nacos/nacos-server:v2.2.3-slim

[root@ubuntu2404 ~]#docker ps
CONTAINER ID   IMAGE                                   COMMAND                  CREATED         STATUS         PORTS                                                                                             NAMES
852f9991653b   nacos/nacos-server:v2.2.3-slim          "bin/docker-startup.…"   4 minutes ago   Up 4 minutes   0.0.0.0:8848->8848/tcp, :::8848->8848/tcp, 0.0.0.0:9848->9848/tcp, :::9848->9848/tcp                   nacos

#登录nacos
http://nacos.wang.org:8848/nacos/

#安装工具
[root@ubuntu2404 ~]#apt update && apt -y install openjdk-21-jdk maven
[root@ubuntu2404 ~]#apt update && apt -y install openjdk-17-jdk maven

#确认版本
[root@ubuntu2404 ~]#mvn -v
Apache Maven 3.6.3
Maven home: /usr/share/maven
Java version: 17.0.9, vendor: Private Build, runtime: /usr/lib/jvm/java-17-openjdk-amd64
Default locale: en_US, platform encoding: UTF-8
OS name: "linux", version: "5.15.0-67-generic", arch: "amd64", family: "unix"

[root@ubuntu2404 ~]#hostname 
ubuntu2204.wang.org

#主机解析
[root@ubuntu2404 ~]#cat /etc/hosts
10.0.0.100 sentinel.wang.org nacos.wang.org
10.0.0.101 ubuntu2204.wang.org

#配置应用
[root@ubuntu2404 sentinel-nacos-demo]#cat src/main/resources/application.yml 
spring:
  application:
    name: sentinel-nacos-demo
  cloud:
    nacos:
      discovery:
        server-addr: nacos.wang.org:8848
    sentinel:
      eager: true
      transport:
        port: 8719
        dashboard: sentinel.wang.org:8080

#编译
[root@ubuntu2404 sentinel-nacos-demo]#mvn clean package -Dmaven.test.skip=true
[INFO] Replacing main artifact with repackaged archive
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------

#运行
[root@ubuntu2404 sentinel-nacos-demo]#java -version
openjdk version "17.0.9" 2023-10-17

#方法1,默认8080
[root@ubuntu2404 sentinel-nacos-demo]#java -jar target/sentinel-nacos-demo-0.0.1-SNAPSHOT.jar 

#方法2：指定端口
[root@ubuntu2404 ~]#java -jar sentinel-nacos-demo-0.0.1-SNAPSHOT.jar --server.port=8888

#方法3：临时指定配置
[root@ubuntu2404 sentinel-nacos-demo]#java -Dspring.cloud.nacos.discovery.server-addr=10.0.0.100:8848 -Dspring.cloud.nacos.config.server-addr=10.0.0.100:8848 -Dspring.cloud.sentinel.transport.dashboard=10.0.0.100:8080 -jar target/sentinel-nacos-demo-0.0.1-SNAPSHOT.jar

#快速刷新页面,观察效果
http://10.0.0.101:8080/hello/zhangqing

Transfer-Encoding: chunked

Date: Thu, 30 Nov 2023 10:22:29 GMT

HTTP/1.1 200

Content-Type: text/plain;charset=UTF-8

Content-Length: 19

Date: Thu, 30 Nov 2023 10:22:30 GMT

HTTP/1.1 429

Transfer-Encoding: chunked

Date: Thu, 30 Nov 2023 10:22:30 GMT

HTTP/1.1 200

Content-Type: text/plain;charset=UTF-8

Content-Length: 19

Date: Thu, 30 Nov 2023 10:22:31 GMT