异步线程中获取到的request为空怎么办

在异步线程中获取到的request为空，这是因为异步线程和原始的请求线程不在同一个线程中，异步线程无法直接访问原始的请求线程的request对象。解决这个问题的方法有两种：

1. 使用Callable接口：可以将异步任务封装成一个Callable对象，并将原始的request对象作为参数传递给Callable对象。在异步任务中，可以通过Future对象获取到Callable对象的返回值，从而获取到request对象。

代码示例：

@RestController
public class MyController {

    @Autowired
    private AsyncService asyncService;

    @RequestMapping("/test")
    public String test(HttpServletRequest request) throws Exception {
        Callable<String> task = () -> {
            // 异步任务中获取request对象
            HttpServletRequest asyncRequest = AsyncRequestContextHolder.getRequest();
            // 处理业务逻辑
            return "success";
        };
        Future<String> future = asyncService.execute(task);
        String result = future.get();
        return result;
    }
}

@Service
public class AsyncService {

    @Autowired
    private AsyncTaskExecutor taskExecutor;

    public <T> Future<T> execute(Callable<T> task) {
        AsyncRequestContextCallable<T> callable = new AsyncRequestContextCallable<>(task);
        return taskExecutor.submit(callable);
    }
}

public class AsyncRequestContextCallable<T> implements Callable<T> {

    private final Callable<T> task;

    private final HttpServletRequest request;

    public AsyncRequestContextCallable(Callable<T> task) {
        this.task = task;
        this.request = AsyncRequestContextHolder.getRequest();
    }

    @Override
    public T call() throws Exception {
        AsyncRequestContextHolder.setRequest(request);
        try {
            return task.call();
        } finally {
            AsyncRequestContextHolder.resetRequest();
        }
    }
}

public class AsyncRequestContextHolder {

    private static final ThreadLocal<HttpServletRequest> requestHolder = new ThreadLocal<>();

    public static void setRequest(HttpServletRequest request) {
        requestHolder.set(request);
    }

    public static HttpServletRequest getRequest() {
        return requestHolder.get();
    }

    public static void resetRequest() {
        requestHolder.remove();
    }
}

2. 使用ServletRequestAttributes：可以使用Spring提供的ServletRequestAttributes类来获取request对象。这个类是一个请求属性的存储器，可以在任何线程中存储和获取请求属性。在异步任务中，可以通过ServletRequestAttributes来获取到原始的request对象。

代码示例：

@RestController
public class MyController {

    @Autowired
    private AsyncService asyncService;

    @RequestMapping("/test")
    public String test(HttpServletRequest request) throws Exception {
        Callable<String> task = () -> {
            // 异步任务中获取request对象
            ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
            HttpServletRequest asyncRequest = attributes.getRequest();
            // 处理业务逻辑
            return "success";
        };
        Future<String> future = asyncService.execute(task);
        String result = future.get();
        return result;
    }
}

@Service
public class AsyncService {

    @Autowired
    private AsyncTaskExecutor taskExecutor;

    public <T> Future<T> execute(Callable<T> task) {
        return taskExecutor.submit(() -> {
            RequestAttributes attributes = RequestContextHolder.getRequestAttributes();
            try {
                RequestContextHolder.setRequestAttributes(attributes, true);
                return task.call();
            } finally {
                RequestContextHolder.resetRequestAttributes();
            }
        });
    }
}

以上两种方法都可以解决异步线程中获取request对象为空的问题，具体选择哪种方法取决于具体的业务需求和开发习惯。