How to migrate to GroupDocs.Viewer 19.8 or higher

This article contains information about migration from the legacy API to GroupDocs.Viewer 20.1 or higher.

Why To Migrate

Here are the key reasons to use the new updated API provided by GroupDocs.Viewer for Java since version 20.1:

  • Viewer class introduced as a single entry point to manage the document rendering process to any supported file format (instead of ViewerHtmlHander / ViewerImageHander classes from previous versions).
  • The overall rendering speed improved dramatically by saving rendered page as soon as it was rendered, not when all pages list were rendered. 
  • Product architecture was redesigned from scratch in order to decreased memory usage (from 10% to 400% approx. depending on document type).
  • Document viewing options simplified so it’s easy to instantiate proper options class and control over document rendering and saving processes.

How To Migrate

Here is a brief comparison of how to display document into HTML form using old and new API.

Old coding style

    //Get Configurations
    ViewerConfig config = Utilities.getConfigurations();

    // Create html handler
    ViewerHtmlHandler htmlHandler = new ViewerHtmlHandler(config);

    // Guid implies that unique document name 
    String guid = "sample.docx";

    //Instantiate the HtmlOptions object
    HtmlOptions options = new HtmlOptions();

    //to get html representations of pages with embedded resources
    options.setResourcesEmbedded(true);

    // Set password if document is password protected. 
    if (documentPassword != null && !documentPassword.isEmpty()) {
        options.setPassword(documentPassword);
    }

    //Get document pages in html form
    List<PageHtml> pages = htmlHandler.getPages(guid, options);

    for (PageHtml page : pages) {
        //Save each page at disk
        Utilities.saveAsHtml(page.getPageNumber() + "_" + documentName, page.getHtmlContent());
    }

New coding style

    LoadOptions loadOptions = new LoadOptions();
    loadOptions.setPassword("documentPassword");
    try (Viewer viewer = new Viewer("sample.docx", loadOptions)) {
        HtmlViewOptions options = HtmlViewOptions.forEmbeddedResources();
        viewer.view(options);
    }

More resources

GitHub Examples

You may easily run the code above and see the feature in action in our GitHub examples:

Free Online App

Along with full-featured Java library we provide simple but powerful free Apps. You are welcome to view Word, PDF, Excel, PowerPoint documents with free to use online GroupDocs Viewer App.

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