springcloud-sentinel
├── src
│   └── main
│       ├── java
│       │   └── com.example
│       │       ├── config
│       │       │   └── SentinelConfig.java
│       │       ├── controller
│       │       │   └── TestSentinelController.java
│       │       ├── service
│       │       │   └── HelloService.java
│       │       └── SentinelApplication.java
│       └── resources
│           └── application.properties
└── pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.example</groupId>
    <artifactId>springboot-sentinel-demo</artifactId>
    <version>1.0-SNAPSHOT</version>
    <properties>
        <java.version>1.8</java.version>
        <spring-boot.version>2.6.3</spring-boot.version>
        <spring-cloud-alibaba.version>2021.0.1.0</spring-cloud-alibaba.version>
    </properties>
    <dependencyManagement>
        <dependencies>
            <!-- Spring Boot 依賴管理 -->
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>${spring-boot.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <!-- Spring Cloud Alibaba 依賴管理 -->
            <dependency>
                <groupId>com.alibaba.cloud</groupId>
                <artifactId>spring-cloud-alibaba-dependencies</artifactId>
                <version>${spring-cloud-alibaba.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>
    <dependencies>
        <!-- Spring Boot Web -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!-- Sentinel 依賴 -->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
        </dependency>
        <!-- Lombok -->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <version>${spring-boot.version}</version>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

# application.properties
spring.application.name=sentinel-demo
server.port=8080
# Sentinel 控制臺(tái)地址
spring.cloud.sentinel.transport.dashboard=localhost:8080
# 取消Sentinel控制臺(tái)懶加載
spring.cloud.sentinel.eager=true
# 設(shè)置應(yīng)用與Sentinel控制臺(tái)的心跳間隔時(shí)間
spring.cloud.sentinel.transport.heartbeat-interval-ms=3000

package com.example.config;
import com.alibaba.csp.sentinel.annotation.aspectj.SentinelResourceAspect;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
/**
 * Sentinel配置類
 * 注冊(cè)SentinelResourceAspect，用于支持@SentinelResource注解
 */
@Configuration
public class SentinelConfig {
    @Bean
    public SentinelResourceAspect sentinelResourceAspect() {
        return new SentinelResourceAspect();
    }
}

package com.example.service;
import com.alibaba.csp.sentinel.annotation.SentinelResource;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import org.springframework.stereotype.Service;
/**
 * 業(yè)務(wù)服務(wù)類
 * 使用@SentinelResource注解定義資源點(diǎn)
 */
@Service
public class HelloService {
    /**
     * 定義一個(gè)資源點(diǎn)，指定blockHandler處理限流異常
     * @param name 參數(shù)
     * @return 返回結(jié)果
     */
    @SentinelResource(value = "sayHello", blockHandler = "sayHelloExceptionHandler")
    public String sayHello(String name) {
        return "Hello, " + name;
    }
    /**
     * 定義一個(gè)資源點(diǎn)，同時(shí)指定blockHandler和fallback
     * blockHandler: 處理限流異常
     * fallback: 處理業(yè)務(wù)異常
     * @param name 參數(shù)
     * @return 返回結(jié)果
     */
    @SentinelResource(value = "circuitBreaker", 
                     fallback = "circuitBreakerFallback", 
                     blockHandler = "sayHelloExceptionHandler")
    public String circuitBreaker(String name) {
        // 模擬業(yè)務(wù)邏輯，當(dāng)name為"test"時(shí)拋出異常
        if ("test".equals(name)) {
            return "Hello, " + name;
        }
        throw new RuntimeException("發(fā)生異常");
    }
    /**
     * 熔斷降級(jí)處理方法，處理業(yè)務(wù)異常
     * @param name 參數(shù)
     * @return 降級(jí)返回結(jié)果
     */
    public String circuitBreakerFallback(String name) {
        return "服務(wù)異常，熔斷降級(jí)，請(qǐng)稍后重試!";
    }
    /**
     * 限流降級(jí)處理方法，處理限流異常
     * @param name 參數(shù)
     * @param ex 限流異常
     * @return 限流返回結(jié)果
     */
    public String sayHelloExceptionHandler(String name, BlockException ex) {
        return "訪問過快，限流降級(jí)，請(qǐng)稍后重試!";
    }
}

package com.example.controller;
import com.example.service.HelloService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
/**
 * 測(cè)試Sentinel的控制器
 */
@RestController
@RequestMapping("/sentinel")
public class TestSentinelController {
    @Autowired
    private HelloService helloService;
    /**
     * 測(cè)試限流功能
     * @param name 參數(shù)
     * @return 返回結(jié)果
     */
    @GetMapping("/hello")
    public String hello(@RequestParam("name") String name) {
        return helloService.sayHello(name);
    }
    /**
     * 測(cè)試熔斷功能
     * @param name 參數(shù)
     * @return 返回結(jié)果
     */
    @GetMapping("/circuit")
    public String circuitBreaker(@RequestParam("name") String name) {
        return helloService.circuitBreaker(name);
    }
}

package com.example;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
/**
 * Sentinel示例應(yīng)用啟動(dòng)類
 */
@SpringBootApplication
public class SentinelApplication {
    public static void main(String[] args) {
        SpringApplication.run(SentinelApplication.class, args);
    }
}

wget https://github.com/alibaba/Sentinel/releases/download/1.8.6/sentinel-dashboard-1.8.6.jar

java -Dserver.port=8080 -jar sentinel-dashboard-1.8.6.jar

http://localhost:8080

mvn spring-boot:run

http://localhost:8080/sentinel/hello?name=world

http://localhost:8080/sentinel/circuit?name=test

http://localhost:8080/sentinel/circuit?name=other

# 配置Sentinel規(guī)則持久化到文件
spring.cloud.sentinel.datasource.ds1.file.file=classpath:sentinel/flow-rule.json
spring.cloud.sentinel.datasource.ds1.file.data-type=json
spring.cloud.sentinel.datasource.ds1.file.rule-type=flow
spring.cloud.sentinel.datasource.ds2.file.file=classpath:sentinel/degrade-rule.json
spring.cloud.sentinel.datasource.ds2.file.data-type=json
spring.cloud.sentinel.datasource.ds2.file.rule-type=degrade

# 配置Sentinel規(guī)則持久化到Nacos
spring.cloud.sentinel.datasource.ds1.nacos.server-addr=localhost:8848
spring.cloud.sentinel.datasource.ds1.nacos.data-id=sentinel-flow-rules
spring.cloud.sentinel.datasource.ds1.nacos.group-id=SENTINEL_GROUP
spring.cloud.sentinel.datasource.ds1.nacos.data-type=json
spring.cloud.sentinel.datasource.ds1.nacos.rule-type=flow
spring.cloud.sentinel.datasource.ds2.nacos.server-addr=localhost:8848
spring.cloud.sentinel.datasource.ds2.nacos.data-id=sentinel-degrade-rules
spring.cloud.sentinel.datasource.ds2.nacos.group-id=SENTINEL_GROUP
spring.cloud.sentinel.datasource.ds2.nacos.data-type=json
spring.cloud.sentinel.datasource.ds2.nacos.rule-type=degrade

package com.example.config;
import com.alibaba.csp.sentinel.adapter.spring.webmvc.callback.BlockExceptionHandler;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.alibaba.csp.sentinel.slots.block.authority.AuthorityException;
import com.alibaba.csp.sentinel.slots.block.degrade.DegradeException;
import com.alibaba.csp.sentinel.slots.block.flow.FlowException;
import com.alibaba.csp.sentinel.slots.block.flow.param.ParamFlowException;
import com.alibaba.csp.sentinel.slots.system.SystemBlockException;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.MediaType;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.PrintWriter;
import java.util.HashMap;
import java.util.Map;
/**
 * 自定義Sentinel全局異常處理
 */
@Configuration
public class SentinelBlockExceptionHandler implements BlockExceptionHandler {
    @Override
    public void handle(HttpServletRequest request, HttpServletResponse response, BlockException e) throws Exception {
        // 設(shè)置響應(yīng)類型
        response.setStatus(429);
        response.setContentType(MediaType.APPLICATION_JSON_VALUE);
        response.setCharacterEncoding("UTF-8");
        Map<String, Object> result = new HashMap<>();
        result.put("code", 429);
        result.put("success", false);
        if (e instanceof FlowException) {
            result.put("message", "請(qǐng)求被限流了");
        } else if (e instanceof DegradeException) {
            result.put("message", "請(qǐng)求被降級(jí)了");
        } else if (e instanceof ParamFlowException) {
            result.put("message", "熱點(diǎn)參數(shù)限流");
        } else if (e instanceof SystemBlockException) {
            result.put("message", "系統(tǒng)規(guī)則限制");
        } else if (e instanceof AuthorityException) {
            result.put("message", "授權(quán)規(guī)則不通過");
        } else {
            result.put("message", "未知限流降級(jí)");
        }
        // 返回JSON數(shù)據(jù)
        PrintWriter out = response.getWriter();
        out.write(new ObjectMapper().writeValueAsString(result));
        out.flush();
        out.close();
    }
}