public static HttpServletRequest getRequest() {
    HttpServletRequest httpServletRequest = null;
    try {
        RequestAttributes requestAttributes = RequestContextHolder.getRequestAttributes();
        if (requestAttributes instanceof ServletRequestAttributes) {
            ServletRequestAttributes servletRequestAttributes = (ServletRequestAttributes) requestAttributes;
            httpServletRequest = servletRequestAttributes.getRequest();
        }
    } catch (Exception e) {
        // 記錄異常，但不向外拋出，以避免可能的業(yè)務(wù)邏輯中斷
        log.error("獲取HttpServletRequest時(shí)發(fā)生異常：", e);
    }
    // 返回獲取到的請(qǐng)求對(duì)象，如果失敗則返回null
    return httpServletRequest;
}

@RestController
@RequestMapping("/test")
@Slf4j
public class TestController {
    @GetMapping("/missing-request-header")
    public String getMissingRequestHeader() {
        // 主線程獲取請(qǐng)求頭信息
        String mainThreadLanguages = ServletUtils.getLanguagesExistProblem();
        log.info("主線程獲取請(qǐng)求頭信息：{}", mainThreadLanguages);
        new Thread(() -> {
            // 子線程獲取請(qǐng)求頭信息
            String subThreadLanguages = ServletUtils.getLanguagesExistProblem();
            log.info("子線程獲取請(qǐng)求頭信息：{}", subThreadLanguages);
        }).start();
        return "success";
    }
}

@Slf4j
public class ServletUtils {

    private final static String X_CLIENT_LANG = "X-CLIENT-LANG";

    public static String  getLanguagesExistProblem() {
        HttpServletRequest request = getRequest();
        Assert.notNull(request);
        String lang =  request.getHeader(X_CLIENT_LANG);
        if (StrUtil.isNotBlank(lang)) {
            return lang;
        }
        return "zh-cn";
    }
}

public static void setRequestAttributes(@Nullable RequestAttributes attributes, boolean inheritable) {
   if (attributes == null) {
      resetRequestAttributes();
   }
   else {
      if (inheritable) {
         inheritableRequestAttributesHolder.set(attributes);
         requestAttributesHolder.remove();
      }
      else {
         requestAttributesHolder.set(attributes);
         inheritableRequestAttributesHolder.remove();
      }
   }
}

@GetMapping("/get-request-header-in-thread")
    public String getRequestHeaderInThread() {
        // 主線程獲取請(qǐng)求頭信息
        String mainThreadLanguages = ServletUtils.getLanguages();
        log.info("主線程獲取請(qǐng)求頭信息：{}", mainThreadLanguages);
        new Thread(() -> {
            try {
                TimeUnit.SECONDS.sleep(5);
            } catch (InterruptedException e) {
                throw new RuntimeException(e);
            }
            // 子線程獲取請(qǐng)求頭信息
            String subThreadLanguages = ServletUtils.getLanguages();
            log.info("子線程獲取請(qǐng)求頭信息：{}", subThreadLanguages);
        }).start();
        return "success";
    }

@GetMapping("/get-request-header-in-thread")
public String getRequestHeaderInThread() {
    // 主線程獲取請(qǐng)求頭信息
    String mainThreadLanguages = ServletUtils.getLanguages();
    CountDownLatch latch = new CountDownLatch(1);
    log.info("主線程獲取請(qǐng)求頭信息：{}", mainThreadLanguages);
    new Thread(() -> {
        try {
            TimeUnit.SECONDS.sleep(5);
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        }
        // 子線程獲取請(qǐng)求頭信息
        String subThreadLanguages = ServletUtils.getLanguages();
        log.info("子線程獲取請(qǐng)求頭信息：{}", subThreadLanguages);
        latch.countDown();
    }).start();
    // 等待計(jì)數(shù)器變?yōu)榱?
    try {
        latch.await();
    } catch (InterruptedException e) {
        throw new RuntimeException(e);
    }
    log.info("確保父子線程全部執(zhí)行完畢");
    return "success";
}

@GetMapping("/get-request-header-in-async-thread/{isJoin}")
    public String getRequestHeaderInThread() {
        // 主線程獲取請(qǐng)求頭信息
        String mainThreadLanguages = ServletUtils.getLanguages();
        log.info("主線程獲取請(qǐng)求頭信息：{}", mainThreadLanguages);
        // 獲取當(dāng)前servletRequestAttributes對(duì)象
        ServletRequestAttributes servletRequestAttributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
        new Thread(() -> {
        // 將servletRequestAttributes設(shè)定到子線程中
        RequestContextHolder.setRequestAttributes(servletRequestAttributes);
            try {
                TimeUnit.SECONDS.sleep(5);
            } catch (InterruptedException e) {
                throw new RuntimeException(e);
            }
            // 子線程獲取請(qǐng)求頭信息
            String subThreadLanguages = ServletUtils.getLanguages();
            log.info("子線程獲取請(qǐng)求頭信息：{}", subThreadLanguages);
        }).start();
        return "success";
    }