How to Merge Two or More HTML Files Together using Java

If you’re managing high quantities of HTML files for various projects/demos, merging those files can make your life a lot easier in the long run. Whether you’re looking to archive/create duplicates of particularly important files, or simply consolidate files pertaining to the same project before sharing with colleagues, including a simple service to facilitate that operation will serve to streamline file administration at scale.

Thankfully, you can merge two or multiple HTM/HTML files with ease using either of our HTML File Merge APIs — and you can get a secure API key to authenticate access for free by registering a free account on our website (this account will yield a limit of 800 API calls per month). Below, I’ll demonstrate how to install the SDK & structure API calls to either API with ready-to-run Java code examples from our API console.

We can start the SDK installation process with Maven by first adding a reference to the pom.xml repository:

<repositories>
    <repository>
        <id>jitpack.io</id>
        <url>https://jitpack.io</url>
    </repository>
</repositories>

And then adding one to the pom.xml dependency:

<dependencies>
<dependency>
    <groupId>com.github.Cloudmersive</groupId>
    <artifactId>Cloudmersive.APIClient.Java</artifactId>
    <version>v4.25</version>
</dependency>
</dependencies>

Once that’s all done, we can use the below code examples to merge no more than two files (there are exactly two file input parameters in this API iteration). First add the imports to the top of your file, and then include your API key just below (where indicated) to authenticate:

// Import classes:
//import com.cloudmersive.client.invoker.ApiClient;
//import com.cloudmersive.client.invoker.ApiException;
//import com.cloudmersive.client.invoker.Configuration;
//import com.cloudmersive.client.invoker.auth.*;
//import com.cloudmersive.client.MergeDocumentApi;
ApiClient defaultClient = Configuration.getDefaultApiClient();
// Configure API key authorization: Apikey
ApiKeyAuth Apikey = (ApiKeyAuth) defaultClient.getAuthentication("Apikey");
Apikey.setApiKey("YOUR API KEY");
// Uncomment the following line to set a prefix for the API key, e.g. "Token" (defaults to null)
//Apikey.setApiKeyPrefix("Token");
MergeDocumentApi apiInstance = new MergeDocumentApi();
File inputFile1 = new File("/path/to/inputfile"); // File | First input file to perform the operation on.
File inputFile2 = new File("/path/to/inputfile"); // File | Second input file to perform the operation on (more than 2 can be supplied).
try {
    byte[] result = apiInstance.mergeDocumentHtml(inputFile1, inputFile2);
    System.out.println(result);
} catch (ApiException e) {
    System.err.println("Exception when calling MergeDocumentApi#mergeDocumentHtml");
    e.printStackTrace();
}

If we’re merging any more than 2 files, we’ll need to call the below API instead. Like before, you’ll just need to add in the imports first, and then configure your API key & file inputs:

// Import classes:
//import com.cloudmersive.client.invoker.ApiClient;
//import com.cloudmersive.client.invoker.ApiException;
//import com.cloudmersive.client.invoker.Configuration;
//import com.cloudmersive.client.invoker.auth.*;
//import com.cloudmersive.client.MergeDocumentApi;
ApiClient defaultClient = Configuration.getDefaultApiClient();
// Configure API key authorization: Apikey
ApiKeyAuth Apikey = (ApiKeyAuth) defaultClient.getAuthentication("Apikey");
Apikey.setApiKey("YOUR API KEY");
// Uncomment the following line to set a prefix for the API key, e.g. "Token" (defaults to null)
//Apikey.setApiKeyPrefix("Token");
MergeDocumentApi apiInstance = new MergeDocumentApi();
File inputFile1 = new File("/path/to/inputfile"); // File | First input file to perform the operation on.
File inputFile2 = new File("/path/to/inputfile"); // File | Second input file to perform the operation on.
File inputFile3 = new File("/path/to/inputfile"); // File | Third input file to perform the operation on.
File inputFile4 = new File("/path/to/inputfile"); // File | Fourth input file to perform the operation on.
File inputFile5 = new File("/path/to/inputfile"); // File | Fifth input file to perform the operation on.
File inputFile6 = new File("/path/to/inputfile"); // File | Sixth input file to perform the operation on.
File inputFile7 = new File("/path/to/inputfile"); // File | Seventh input file to perform the operation on.
File inputFile8 = new File("/path/to/inputfile"); // File | Eighth input file to perform the operation on.
File inputFile9 = new File("/path/to/inputfile"); // File | Ninth input file to perform the operation on.
File inputFile10 = new File("/path/to/inputfile"); // File | Tenth input file to perform the operation on.
try {
    byte[] result = apiInstance.mergeDocumentHtmlMulti(inputFile1, inputFile2, inputFile3, inputFile4, inputFile5, inputFile6, inputFile7, inputFile8, inputFile9, inputFile10);
    System.out.println(result);
} catch (ApiException e) {
    System.err.println("Exception when calling MergeDocumentApi#mergeDocumentHtmlMulti");
    e.printStackTrace();
}

After that, you’re all set — no more code required. It’s important to note that these APIs by themselves will not output a downloadable HTML file; rather, they will output the encoding to generate a file in the output stage of your application logic.