Process of editing PowerPoint PPTX documents in Java

introduction

Building applications for programmatically editing Open Office XML (OOXML) documents such as PowerPoint, Excel, and Word has never been easier. Depending on the project scope, Java developers can leverage open source third-party libraries in their code, or use simplified plug-in APIs to manipulate content stored and displayed in OOXML structures.

In this article, we will discuss the structure of PowerPoint presentation XML (PPTX) files specifically and learn the basic process of how to manipulate PPTX content. We will then discuss a popular open source Java library for programmatic manipulation of PPTX files (particularly instances of replacement text strings) and then explore a free third-party API solution that can help simplify the process and reduce local memory consumption.

What is the structure of PowerPoint PPTX files?

Like all OOXML files, the PowerPoint PPTX file is structured as a ZIP archive containing a series of hierarchical organization of XML files. They are essentially a series of directories, most of which are responsible for storing and scheduling the resources we see in PowerPoint applications (or any PPTX file readers).

PPTX archives start with a basic root structure that defines the various content types (for example, multimedia content) we see in PowerPoint. The core of the PPTX document is at the directory level, and components such as slides (e.g., , etc.), slide layouts (e.g., templates), slide masters (e.g., global styles and placeholders), and other content (e.g., charts, media, and themes) are clearly organized. The relationship between interdependent components in a PPTX file is stored in_relsIn the directory.relsin XML file. These relationship files are automatically updated when changes are made to slides or other content.

Given this file structure, suppose we want to manually replace the text string in the PowerPoint slide without opening the file using PowerPoint or any other PPTX reader. To do this, we first need to convert the PPTX archive to a ZIP file (with.zipextension), then unzip its contents. After that, we will checkppt/Files, which lists slides in order, and then navigate toppt/slides/Directory to find the target slide (e.g.). To modify the slide, we will open, find the text we need to run (usually the structure is<a:t> “string” </a:t>,lie in<a:r></a:r>within the tag), and replace the text content with the new string. Then, we will check_relsDirectory to ensure that the slide relationship remains intact; after that, we repackage the files as ZIP archives and reintroduce them.pptxExtension.

Programmatically change PPTX files in Java

To handle the exact same process in Java, we need to consider several different possibilities based on the context. Obviously, no one wants to temporarily map the entire OOXML structure into a custom Java program—so we need to determine whether it makes more sense to use an open source library or a plug-and-play API service based on project constraints.

If we choose the open source route,Apache POIWould be a good choice. Apache POI is an open source Java API designed to help developers handle Microsoft documents, including PowerPoint PPTX (as well as Excel XLSX, Word DOCX, etc.).

For projects involving PPTX files, we first need to import the relevant Apache POI class for PowerPoint projects (for example,XMLSlideShow、XSLFSlideandXSLFTextShape). Then, we will useXMLSlideShowClass loading PPTX file, callinggetSlides()Method, useXSLFTextShapeClass filters text content and callsgetText()andsetText()Method to replace a specific string.

This will be totally feasible, but it is worth noting that the challenge of using an open source library like Apache POI is how memory is handled. Apache POI loads all data into local memory, and although there are some workarounds—for example, increasing the JVM heap size or implementing a stream-based API—we can consume a lot of resources when dealing with large-scale PPTX files.

Using third-party APIs to solve

If we cannot handle PPTX editing workflow locally, a cloud API solution may be helpful. This solution offloads most of the file processing work to an external server and returns results, reducing overhead. As an added benefit, it also simplifies the process of building string replacement requests. We will look at one of the following API solutions.

The following example Java code can be used to call a free Web API that replaces all string instances found in the PPTX documentation. The API is free to use and requires a free API key, and its parameters are extremely simple and easy to use.

To build our API calls, we first need to incorporate the client library into our Maven project. We willAdd the following toJitPack) Repository Quote:

<repositories>
    <repository>
        <id></id>
        <url></url>
    </repository>
</repositories>

Next, we willAdd the following dependency references to:

<dependencies>
    <dependency>
        <groupId></groupId>
        <artifactId></artifactId>
        <version>v4.25</version>
    </dependency>
</dependencies>

Once we have done this, we now copy and add the following import class to the top of the file:

// Import classes:
//import ;
//import ;
//import ;
//import .*;
//import ;

Now, we will initialize the API client with the following code and then configure API key authorization.setAPIKey()The method will capture our API key string:

ApiClient defaultClient = ();

// Configure API key authorization: Apikey
ApiKeyAuth Apikey = (ApiKeyAuth) ("Apikey");
("YOUR API KEY");
// Uncomment the following line to set a prefix for the API key, . "Token" (defaults to null)
//("Token");

Finally, we will instantiate the API client using the following code, configure the replacement operation, and execute the replacement process (returning abyte[]Array), and catch/record errors:

EditDocumentApi apiInstance = new EditDocumentApi();
ReplaceStringRequest reqConfig = new ReplaceStringRequest(); // ReplaceStringRequest | Replacement document configuration input
try {
    byte[] result = (reqConfig);
    (result);
} catch (ApiException e) {
    ("Exception when calling EditDocumentApi#editDocumentPptxReplace");
    ();
}

The following JSON defines our request structure; we will use it in our code to configure the parameters of the string replacement operation.

{
  "InputFileBytes": "string",
  "InputFileUrl": "string",
  "MatchString": "string",
  "ReplaceString": "string",
  "MatchCase": true
}

We can prepare a PPTX document for this API request by reading the file into a byte array and converting it into a Base64-encoded string.

Summarize

In this article, we discuss how PowerPoint PPTX files are structured and how this structure enables them to easily edit PowerPoint documents outside of PPTX readers. We then suggest the Apache POI library as an open source solution for Java developers to programmatically replace strings in PPTX files, and then explore a free third-party API solution for handling the same process at a lower local memory cost.

The above is the detailed content of the operation process of editing PowerPoint PPTX documents in Java. For more information about editing PowerPoint PPTX documents in Java, please pay attention to my other related articles!