这是一个散列处理器，我想在其中使用SHA-1算法对FileInputStream进行散列，然后将散列添加到“HashValue”下的交换标头中
@Component
公共类FileContentHashExpression实现表达式{

@Override
    public <T> T evaluate(Exchange exchange, Class<T> type) {
        // TODO Check for String type and generic file message
        if (type != String.class){
            throw new IllegalArgumentException("This is String only expression");
        }
        try (FileInputStream fileInputStream = new FileInputStream(((File)exchange.getIn(GenericFileMessage.class).getGenericFile().getFile()))) {
            exchange.getIn().setHeader("HashValue", DigestUtils.sha1(fileInputStream));
            return (T) (DigestUtils.sha1(fileInputStream));
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }