Sentinel接入SpringCloud（一）

目标:手动配置限流资源保护
工具：IDEA–2020.1、Sentinel、本地服务器（作为测试）
学习目标:手动配置限流资源保护
本次学习的工程下载链接放到文本最后面

创建一个基于Springboot的项目，并集成Greenwich.SR2版本的依赖，并添加Sentinel依赖包：

<properties>
    <java.version>1.8</java.version>
    <spring-cloud.version>Greenwich.SR2</spring-cloud.version>
</properties>

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>com.alibaba.cloud</groupId>
        <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
        <exclusions>
            <exclusion>
                <groupId>org.junit.vintage</groupId>
                <artifactId>junit-vintage-engine</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
</dependencies>

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-dependencies</artifactId>
            <version>${spring-cloud.version}</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-alibaba-dependencies</artifactId>
            <version>2.1.1.RELEASE</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>

</dependencyManagement>

创建一个REST接口，并通过@SentinelResource配置限流保护资源
//创建一个REST接口，并通过@SentinelResource配置限流保护资源

@RestController
public class HelloController {
//配置后触发限流调用blockHandler中的参数资源多刷新界面几次就能看到效果了
@SentinelResource(value = “hello”,blockHandler = “blockHandlerHello”)
@GetMapping(“/say”)
public String hello(){
return “hello ,xmaven”;
}
public String blockHandlerHello(BlockException e){
return “被限流了”;
} }
手动配置限流规则

//手动配置限流规则，通过Sentinel的InitFunc SPI接口来实现，只需要实现自己的InitFunc接口，并在init方法中编写规则加载的逻辑即可

//还需要在resource下的META-INF.services下配置这个包的路径com.xmaven.FlowRuleInitFunc
public class FlowRuleInitFunc implements InitFunc{
@Override
public void init() throws Exception {
List rules=new ArrayList<>();
FlowRule rule=new FlowRule();
rule.setCount(1);
rule.setResource(“hello”);
rule.setGrade(RuleConstant.FLOW_GRADE_QPS);
rule.setLimitApp(“default”);
rules.add(rule);
FlowRuleManager.loadRules(rules);
} }
还要在Resource目录下创建META-INF/com.alibaba.csp.sentinel.init.InitFunc文件,文件就是自动以扩展点的全路径

       com.xmaven.FlowRuleInitFunc

启动服务后，访问http://localhost:8090/say方法，多刷新访问几次，超过设定的阈值，就会触发限流

下载链接：spring-cloud-sentinel-sample.rar

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Sentinel接入SpringCloud（一）

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