用aspose-word解决doc转docx工具类

首先pom中添加依赖（官网的收费！）

<dependency>
   <groupId>com.aspose</groupId>
   <artifactId>aspose-words</artifactId>
   <version>20.4.0</version>
   <scope>system</scope>
   <systemPath>${project.basedir}/lib/aspose-words.jar</systemPath>
</dependency>

以下为工具类：

/**
 * 文档工具类
 */
public class DocumentUtils{
    /**
     * doc文件的输入流转换成docx的输入流
     * @param inputStream
     * @return
     */
    @SneakyThrows
    public static InputStream docToDocx(InputStream inputStream){
        if(FileMagic.valueOf(inputStream) == FileMagic.OLE2) {
            Document document = new Document(inputStream);
            ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
            document.save(outputStream, 20);
            closeStream(outputStream);
            return new ByteArrayInputStream(outputStream.toByteArray());
        }else{
            return inputStream;
        }
    }

    private static void closeStream(OutputStream outputStream) throws IOException {
        if(outputStream != null){
            outputStream.close();
        }
    }

    private static void closeStream(InputStream inputStream) throws IOException {
        if(inputStream != null){
            inputStream.close();
        }
    }
}