【SpringCloud教程】8.SpringCloud Alibaba服务保护Sentinel代码控制限流

上篇讲到了Sentinel 简单使用和Sentinel dashboard 控制台整合，这篇主要讲到通过注解和自定义编码来实现限流。

import com.alibaba.csp.sentinel.slots.block.RuleConstant;
import com.alibaba.csp.sentinel.slots.block.flow.FlowRule;
import com.alibaba.csp.sentinel.slots.block.flow.FlowRuleManager;
import org.springframework.context.annotation.Configuration;

import javax.annotation.PostConstruct;
import java.util.ArrayList;
import java.util.List;


@Configuration
public class SentinelConfig {

    @PostConstruct
    public void init() {
        List rules = new ArrayList<>();
        FlowRule rule1 = new FlowRule();
        rule1.setResource("userQps");
        // QPS控制在1，每秒钟运行1个请求
        rule1.setCount(1);
        // QPS限流
        rule1.setGrade(RuleConstant.FLOW_GRADE_QPS);
        rule1.setLimitApp("default");
        rules.add(rule1);
        FlowRuleManager.loadRules(rules);
    }
}

@SentinelResource 对应 配置类的resource，代码如下：

public String qpsException(BlockException e) {
    e.printStackTrace();
    return "当前访问人数过多，稍后重试!";
}

@GetMapping("testAnnotation")
@SentinelResource(value = "userQps", blockHandler = "qpsException")
public String testAnnotation() throws InterruptedException {
    Thread.sleep(1000);
    return "terry";
}

被限流后：

    public String qpsException(BlockException e) {
        e.printStackTrace();
        return "当前访问人数过多，稍后重试!";
    }

    @RequestMapping("/testCode")
    public String orderToMember() {
        Entry entry = null;
        try {
            entry = SphU.entry("userQps");
            return "terry";
        } catch (BlockException e) {
            // 限流的情况就会进入到Exception
            return qpsException(e);
        } finally {
            // 避免调用链记录异常
            if (entry != null) {
                entry.exit();
            }
        }
    }

测试：

被限流后：