How to split PDFs using Java

Split PDF files using our split PDF Java API. Start with 200 free credits — no payment required. Different operations consume different credit amounts, so the number of PDF documents you can generate will vary. Create a free account(opens in a new tab) to get your API key.

Splitting a PDF document is a common use case when working with PDFs and PDF forms because it enables logical archiving of information. A PDF splitting API automates the process of splitting documents in your workflow.

For example, a financial services company might receive a single PDF with clients’ personal and financial information, as well as a questionnaire. By integrating a PDF splitting API into the workflow, you can automatically split these documents into logical parts that can be stored separately.

Nutrient DWS Processor API

Document splitting is just one of our 30+ PDF API tools. You can combine our splitting tool with other tools to create complex document processing workflows, such as:

• Converting MS Office files and images into PDFs and splitting them
• Performing OCR on documents and splitting them
• Watermarking and flattening PDFs and splitting them

Step 1 — Creating a free account on Nutrient

Go to our website(opens in a new tab), where you’ll see the page below, prompting you to create your free account.

Once you’ve created your account, you’ll see a page showing an overview of your plan details.

You’ll start with 200 credits to process and can access all our PDF API tools.

Step 2 — Obtaining the API key

After you’ve verified your email, you can get your API key from the dashboard. In the menu on the left, click API keys. You’ll see the following page, which is an overview of your keys.

Copy the Live API key — you’ll need it for the split PDF API.

Step 3 — Setting up folders and files

For this tutorial, use IntelliJ IDEA as your code editor. Create a new project called split_pdf. You can choose any location, but select Java as the language, Gradle as the build system, and Groovy as the Gradle DSL.

Create a new directory in your project. Right-click your project’s name and select New > Directory. From there, choose the src/main/java option. Create a class file inside the src/main/java folder called processor.java, and create two folders in the root folder called input_documents and processed_documents.

Paste your PDF file inside the input_documents folder.

Your folder structure will look like this:

split_pdf
├── input_documents
|    └── document.pdf
├── processed_documents
├── src
|    └── main
|        └── java
|            └── processor.java

Step 4 — Installing dependencies

Install two libraries:

• OkHttp — This library makes API requests.
• JSON — This library will parse the JSON payload.

Open the build.gradle file and add the following dependencies to your project:

dependencies {
    implementation 'com.squareup.okhttp3:okhttp:4.9.2'
    implementation 'org.json:json:20210307'
}

Once done, click the Add Configuration button. This will open a dropdown menu. Next, select Application.

Now, fill the form with the required details. Most of the fields will be prefilled, but you need to select java 18 in the module field and add -cp split_pdf_4.main in the main class.

To apply settings, click the Apply button.

Step 5 — Writing the code

Open the processor.java file and paste the code below into it:

package com.example.pspdfkit;

import java.io.File;
import java.io.IOException;
import java.nio.file.FileSystems;
import java.nio.file.Files;
import java.nio.file.StandardCopyOption;

import org.json.JSONArray;
import org.json.JSONObject;

import okhttp3.MediaType;
import okhttp3.MultipartBody;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.RequestBody;
import okhttp3.Response;

public final class Processor {
  public static void main(final String[] args) throws IOException {
    final RequestBody firstHalfBody = new MultipartBody.Builder()
      .setType(MultipartBody.FORM)
      .addFormDataPart(
        "document",
        "document.pdf",
        RequestBody.create(
          MediaType.parse("application/pdf"),
          new File("input_documents/document.pdf")
        )
      )
      .addFormDataPart(
        "instructions",
        new JSONObject()
          .put("parts", new JSONArray()
            .put(new JSONObject()
              .put("file", "document")
              .put("pages", new JSONObject()
                .put("end", -6)
              )
            )
          ).toString()
      )
      .build();

    final Request firstHalfRequest = new Request.Builder()
      .url("https://api.nutrient.io/build")
      .method("POST", firstHalfBody)
      .addHeader("Authorization", "Bearer YOUR_API_KEY_HERE")
      .build();

    final RequestBody secondHalfBody = new MultipartBody.Builder()
      .setType(MultipartBody.FORM)
      .addFormDataPart(
        "document",
        "document.pdf",
        RequestBody.create(
          MediaType.parse("application/pdf"),
          new File("input_documents/document.pdf")
        )
      )
      .addFormDataPart(
        "instructions",
        new JSONObject()
          .put("parts", new JSONArray()
            .put(new JSONObject()
              .put("file", "document")
              .put("pages", new JSONObject()
                .put("start", -5)
              )
            )
          ).toString()
      )
      .build();

    final Request secondHalfRequest = new Request.Builder()
      .url("https://api.nutrient.io/build")
      .method("POST", secondHalfBody)
      .addHeader("Authorization", "Bearer YOUR_API_KEY_HERE")
      .build();

    executeRequest(firstHalfRequest, "processed_documents/first_half.pdf");
    executeRequest(secondHalfRequest, "processed_documents/second_half.pdf");
  }

  private static void executeRequest(final Request request, final String outputFileName) throws IOException {
    final OkHttpClient client = new OkHttpClient()
      .newBuilder()
      .build();

    final Response response = client.newCall(request).execute();

    if (response.isSuccessful()) {
      Files.copy(
        response.body().byteStream(),
        FileSystems.getDefault().getPath(outputFileName),
        StandardCopyOption.REPLACE_EXISTING
      );
    } else {
      // Handle the error.
      throw new IOException(response.body().string());
    }
  }
}

Code explanation

In the code above, you import all the packages required to run the code and create a class called processor. In the main function, you first create the request body for the API call that contains all the instructions for splitting the PDF. Then you call the API to process the instructions.

Finally, you call the executeRequest function and pass both form data variables: firstHalfRequest and secondHalfRequest. The API response is stored in the processed_documents folder.

Output

To execute the code, click the Run button (which is a little green arrow). This is next to the field that says Processor, which is where you set the configuration.

On successful execution, it’ll create two files in the processed_documents folder: first_half.pdf and second_half.pdf. The folder structure will look like this:

split_pdf
├── input_documents
|    └── document.pdf
├── processed_documents
|    └── first_half.pdf
|    └── second_half.pdf
├── src
|    └── main
|        └── java
|            └── processor.java

Additional resources

Explore more ways to work with Nutrient API:

• Postman collection — Test API endpoints directly in Postman
• Zapier integration — Automate document workflows without code
• MCP Server — PDF automation for LLM applications
• JavaScript client — Official JavaScript/TypeScript library

Conclusion

You’ve learned how to split PDF files for your Java application using our split PDF API.

You can integrate these functions into your existing applications. With the same API token, you can perform other operations like merging documents into a single PDF, adding watermarks, and more. To get started with a free trial, sign up(opens in a new tab) here.

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