springboot 接口并发限制(Semaphore)

@RestController
@RequestMapping({"/Test"})
public class test {

    private static final Log logger = LogFactory.getLog(test.class);
    // 使用 Semaphore 并发限制3个 超过阻塞
    private final Semaphore permit = new Semaphore(3, true);


    @RequestMapping(value = {"/port"},method = {RequestMethod.POST})
    public String portCollect(@RequestBody String in) {
        logger.info("in_item=" + in);
        
        String aa = "";
        try {
            // 获取令牌
            permit.acquire();
            Thread.sleep(20000);
            aa = "222";
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            // 释放令牌
            permit.release();
            return aa;
        }

    }

}