前言：作者查阅了Sentinel官网、51CTO、CSDN、码农家园、博客园等很多技术文章都没有很准确的springmvc集成Sentinel的示例，因此整理了本文，主要介绍SpringMvc集成Sentinel
SpringMvc集成Sentinel
一、Sentinel 介绍
随着微服务的流行，服务和服务之间的稳定性变得越来越重要。Sentinel 是面向分布式、多语言异构化服务架构的流量治理组件，主要以流量为切入点，从流量路由、流量控制、流量整形、熔断降级、系统自适应过载保护、热点流量防护等多个维度来帮助开发者保障微服务的稳定性。
GitHub主页：https://github.com/alibaba/Sentinel
中文文档：https://sentinelguard.io/zh-cn/docs/introduction.html
控制台文档：https://sentinelguard.io/zh-cn/docs/dashboard.html
核心类解析：https://github.com/alibaba/Sentinel/wiki/Sentinel-核心类解析
Sentinel示例项目：https://github.com/alibaba/Sentinel/tree/master/sentinel-demo
二、Sentinel 基本概念
资源
资源是 Sentinel 的关键概念。它可以是 Java 应用程序中的任何内容，例如，由应用程序提供的服务，或由应用程序调用的其它应用提供的服务，甚至可以是一段代码。在接下来的文档中，我们都会用资源来描述代码块。
只要通过 Sentinel API 定义的代码，就是资源，能够被 Sentinel 保护起来。大部分情况下，可以使用方法签名，URL，甚至服务名称作为资源名来标示资源。
规则
围绕资源的实时状态设定的规则，可以包括流量控制规则、熔断降级规则以及系统保护规则。所有规则可以动态实时调整。
三、springMVC集成Sentinel
这里用的是spring
<spring.version>5.3.18</spring.version>
<servlet.api.version>2.5</servlet.api.version> <sentinel.version>1.8.6</sentinel.version>
1、springmvc项目引入依赖pom
<!-- 这是sentinel的核心依赖 -->
<dependency>
<groupId>com.alibaba.csp</groupId>
<artifactId>sentinel-core</artifactId>
<version>${sentinel.version}</version>
</dependency>
<!-- 这是将自己项目和sentinel-dashboard打通的依赖 -->
<dependency>
<groupId>com.alibaba.csp</groupId>
<artifactId>sentinel-transport-simple-http</artifactId>
<version>${sentinel.version}</version>
</dependency>
<!-- 这是使用sentinel对限流资源进行AOP -->
<dependency>
<groupId>com.alibaba.csp</groupId>
<artifactId>sentinel-annotation-aspectj</artifactId>
<version>${sentinel.version}</version>
</dependency>
<!--这是使用sentinel适配Web Servlet的依赖-->
<dependency>
<groupId>com.alibaba.csp</groupId>
<artifactId>sentinel-web-servlet</artifactId>
<version>${sentinel.version}</version>
</dependency>
<!-- 这是使用sentinel热点参数限流功能依赖 -->
<dependency>
<groupId>com.alibaba.csp</groupId>
<artifactId>sentinel-parameter-flow-control</artifactId>
<version>${sentinel.version}</version>
</dependency>2、添加配置文件
在application.properties下创建同级文件sentinel.properties，内容如下
# 集成到sentinel的项目名称
project.name=spring-sentinel-demo
# 对应的sentinel-dashboard地址
csp.sentinel.dashboard.server=localhost:80803、添加配置类引入配置文件
创建配置类SentinelAspectConfiguration并引入配置文件sentinel.properties
import com.alibaba.csp.sentinel.annotation.aspectj.SentinelResourceAspect;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;
import org.springframework.context.annotation.PropertySources;
@Configuration
@PropertySources({@PropertySource("classpath:/sentinel.properties")})
public class SentinelAspectConfiguration {
@Bean
public SentinelResourceAspect sentinelResourceAspect() {
return new SentinelResourceAspect();
}
}4、web.xml新增如下过滤器配置
<filter>
<filter-name>SentinelCommonFilter</filter-name>
<filter-class>com.alibaba.csp.sentinel.adapter.servlet.CommonFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>SentinelCommonFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>接入 filter 之后，所有访问的 Web URL 就会被自动统计为 Sentinel 的资源---来源于 https://sentinelguard.io/zh-cn/docs/open-source-framework-integrations.html
开源框架适配的Web 适配下的Web Servlet
5、创建Controller接口
@Controller
public class WebMvcTestController {
@GetMapping("/hello")
@ResponseBody
public String apiHello(String id) {
System.out.println("id = " + id);
Date date = new Date();
System.out.println("date = " + date);
return "Hello!";
}
@GetMapping("/doBusiness")
@ResponseBody
public String doBusiness(String id) {
System.out.println("doBusiness = ");
return "Oops...";
}
}6、下载控制台-即图形化实时监控平台
参考 https://sentinelguard.io/zh-cn/docs/dashboard.html Sentinel 控制台的下载和启动
访问 https://github.com/alibaba/Sentinel/releases/tag/1.8.6
点击下载
7、运行控制台
java -Dserver.port=8080 -Dcsp.sentinel.dashboard.server=localhost:8080 -Dproject.name=sentinel-dashboard -jar sentinel-dashboard.jar
运行控制台后运行springmvc项目，然后访问某一个路径，就可以在控制台看到了，实时监控如果这个路径没有被访问是显示不出来的
这个时候我们配置限流为即Qps为2
8、测试限流
这里我们用postman进行压测，填写请求的路径保存。并点击run调出压测执行器
执行后查看结果如下
四、自定义异常返回
1、定义如下接口(这里只进行了常见的url定义方式的定义)
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;
@Controller
@RequestMapping("/test")
public class WebMvcTestController {
/**
* 1.未配置流控规则 1000次请求没有间隔发起请求，应该在1秒中完成09:44:33
* @param id
* @return
*/
@RequestMapping("/RequestMapping")
@ResponseBody
public String RequestMapping(String id) {
return "RequestMapping!";
}
@GetMapping("/GetMapping")
@ResponseBody
public String GetMapping(String id) {
return "GetMapping...";
}
@PostMapping("/PostMapping")
@ResponseBody
public String PostMapping(String id) {
return "PostMapping...";
}
/*
* 路径变量（Path Variables）：使用花括号 {} 来标记路径中的变量，并通过 @PathVariable 注解将其绑定到方法参数上
* */
@GetMapping("/GetMapping/{id}")
@ResponseBody
public String apiFoo(@PathVariable("id") Long id) {
return "Hello " + id;
}
/*
* Ant风格的路径匹配：
* 使用 ? 表示任意单个字符，
* * 表示任意多个字符（不包含路径分隔符 /），
* ** 表示任意多个字符（包含路径分隔符 /）。
* */
@GetMapping("/Ant/*/{id}")
@ResponseBody
public String Ant(@PathVariable("id") Long id) {
return "Ant " + id;
}
/*
* 正则表达式路径匹配：使用 @RequestMapping 注解的 value 属性结合正则表达式来定义请求路径。
* */
@GetMapping(value = "/users/{id:\\d+}")
@ResponseBody
public String pattern(@PathVariable("id") int id) {
return "Ant " + id;
}
}2、自定义限流返回处理Handler
import com.alibaba.csp.sentinel.adapter.servlet.callback.UrlBlockHandler;
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.alibaba.fastjson.JSON;
import org.springframework.context.ApplicationContext;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.mvc.condition.PatternsRequestCondition;
import org.springframework.web.servlet.mvc.method.RequestMappingInfo;
import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping;
import org.springframework.web.util.UrlPathHelper;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.*;
public class SentinelExceptionHandler implements UrlBlockHandler {
@Override
public void blocked(HttpServletRequest request, HttpServletResponse httpServletResponse, BlockException e) throws IOException {
String contextPath = request.getContextPath();
String servletPath = request.getServletPath();
String requestURI = request.getRequestURI();
String url = request.getRequestURL().toString();
System.out.println("servletPath = " + servletPath);
System.out.println("requestURI = " + requestURI);
System.out.println("url = " + url);
if (contextPath == null) {
contextPath = "";
}
ApplicationContext controllerApplicationContext = LiteFlowApplicationContext.getControllerApplicationContext();
RequestMappingHandlerMapping handlerMapping = controllerApplicationContext.getBean(RequestMappingHandlerMapping.class);
// 查找匹配的处理方法
Class<?> returnType = null;
Map<RequestMappingInfo, HandlerMethod> handlerMethods = handlerMapping.getHandlerMethods();
for (Map.Entry<RequestMappingInfo, HandlerMethod> entry : handlerMethods.entrySet()) {
RequestMappingInfo requestMappingInfo = entry.getKey();
HandlerMethod handlerMethod = entry.getValue();
//匹配url
if (requestMappingInfo.getPatternsCondition().getPatterns().contains(requestURI)) {
System.out.println("Controller: " + handlerMethod.getBeanType().getName());
System.out.println("Method: " + handlerMethod.getMethod().getName());
System.out.println("getReturnType: " + handlerMethod.getMethod().getReturnType());
returnType = handlerMethod.getMethod().getReturnType();
break;
}
//匹配路径带参数的url
UrlPathHelper pathHelper = new UrlPathHelper();
String lookupPath = pathHelper.getPathWithinApplication(request);
PatternsRequestCondition patternsCondition = requestMappingInfo.getPatternsCondition();
if (patternsCondition != null && patternsCondition.getMatchingPatterns(lookupPath).size() > 0) {
System.out.println("Controller1111: " + handlerMethod.getBeanType().getName());
System.out.println("Method111: " + handlerMethod.getMethod().getName());
System.out.println("getReturnType: " + handlerMethod.getMethod().getReturnType());
returnType = handlerMethod.getMethod().getReturnType();
break;
}
}
httpServletResponse.setContentType("application/json;charset=utf-8");
ResponseData data = null;
if (returnType != null) {
if (returnType == String.class) {
String str = "返回类型为字符串方法限流";
httpServletResponse.getWriter().write(str);
return;
} else if (returnType == Integer.class) {
httpServletResponse.getWriter().write(new Integer(1));
return;
} else if (returnType == Long.class) {
httpServletResponse.getWriter().write(2);
return;
} else if (returnType == Double.class) {
} else if (returnType == Boolean.class) {
} else if (returnType == Float.class) {
} else if (returnType == Byte.class) {
}
}
//BlockException 异常接口,包含Sentinel的五个异常
// FlowException 限流异常
// DegradeException 降级异常
// ParamFlowException 参数限流异常
// AuthorityException 授权异常
// SystemBlockException 系统负载异常
if (e instanceof FlowException) {
data = new ResponseData(-1, "流控规则被触发......");
} else if (e instanceof DegradeException) {
data = new ResponseData(-2, "降级规则被触发...");
} else if (e instanceof AuthorityException) {
data = new ResponseData(-3, "授权规则被触发...");
} else if (e instanceof ParamFlowException) {
data = new ResponseData(-4, "热点规则被触发...");
} else if (e instanceof SystemBlockException) {
data = new ResponseData(-5, "系统规则被触发...");
}
httpServletResponse.getWriter().write(JSON.toJSONString(data));
}
}3、使用自定义限流处理类
import com.alibaba.csp.sentinel.adapter.servlet.callback.WebCallbackManager;
import org.springframework.context.annotation.Configuration;
@Configuration
public class SentinelConfig {
public SentinelConfig() {
WebCallbackManager.setUrlBlockHandler(new SentinelExceptionHandler());
}
}4、配置限流并测试结果
当开启限流后访问触发自定义UrlBlockHandler后结果如下
访问对应得url后控制台打印
servletPath = /test/RequestMapping
requestURI = /test/RequestMapping
url = http://localhost:8081/test/RequestMapping
Controller: org.example.WebMvcTestController
Method: RequestMapping
getReturnType: class java.lang.String
servletPath = /test/GetMapping
requestURI = /test/GetMapping
url = http://localhost:8081/test/GetMapping
Controller: org.example.WebMvcTestController
Method: GetMapping
getReturnType: class java.lang.String
servletPath = /test/PostMapping
requestURI = /test/PostMapping
url = http://localhost:8081/test/PostMapping
Controller: org.example.WebMvcTestController
Method: PostMapping
getReturnType: class java.lang.String
servletPath = /test/GetMapping/4
requestURI = /test/GetMapping/4
url = http://localhost:8081/test/GetMapping/4
Controller1111: org.example.WebMvcTestController
Method111: apiFoo
getReturnType: class java.lang.String
servletPath = /test/Ant/a/5
requestURI = /test/Ant/a/5
url = http://localhost:8081/test/Ant/a/5
Controller1111: org.example.WebMvcTestController
Method111: Ant
getReturnType: class java.lang.String
servletPath = /test/users/5
requestURI = /test/users/5
url = http://localhost:8081/test/users/5
Controller1111: org.example.WebMvcTestController
Method111: pattern
getReturnType: class java.lang.String5、页面效果如下
五、springboot集成Sentinel
因为springboot集成文章较多，这里不多做赘述
Sentinel 与 Spring Boot/Spring Cloud 的整合见 Sentinel Spring Cloud Starter。
作者：京东健康 马仁喜
来源：京东云开发者社区 转载请注明来源
