通过计数器实现限流

@RestController
public class Demo1_CounterTest {

    Counter counter = new CounterBasic();

    int limit = 3000;

    @RequestMapping("/hello")
    public void hello() {

        counter.incr();
        // 请求超过限制
        if (counter.get() > limit) {
            // 限流
            return;
        }

        try {
            // 业务逻辑
        } finally {
            // 处理完毕， 数量减一
            counter.decr();
        }
    }
}