How can I extract content from files within a zip archive using Apache Tika in Java?

Extracting Content from Files within a Zip Archive Using Apache Tika

Problem:

Develop a Java program that reads the contents of files stored within a zip archive utilizing Apache Tika. The zip archive contains various file formats (such as txt, pdf, and docx).

Solution:

To achieve the desired functionality, follow these steps:

1. Parse the Zip Archive:

   • Utilize ZipInputStream to iterate through the entries in the zip archive.
   • Extract only the files of interest (e.g., txt, pdf, docx).

2. Invoke Apache Tika:

   • Create an instance of a text handler (e.g., BodyContentHandler) for capturing the extracted content.
   • Instantiate a parser (e.g., AutoDetectParser) to identify the file type and apply the appropriate parsing method.

3. Extract and Convert Content:

   • Parse each extracted file through the parser, extracting the content into the text handler.
   • Convert any binary or unsupported data into a String format.

4. Consolidate Extracted Content:

   • Store the extracted content from all the files into a temporary list.
   • Combine the contents of the individual files into a single String for further processing or display.

Code Snippet (Modified):

<code class="java">import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;

import org.apache.tika.exception.TikaException;
import org.apache.tika.metadata.Metadata;
import org.apache.tika.parser.AutoDetectParser;
import org.apache.tika.parser.BodyContentHandler;
import org.apache.tika.parser.ParseContext;
import org.apache.tika.parser.Parser;
import org.apache.tika.sax.BodyContentHandlerFactory;
import org.xml.sax.SAXException;

public class ImprovedZipExtractor {

    public static void main(String[] args) {
        List&lt;String&gt; tempString = new ArrayList&lt;&gt;();
        StringBuffer sbf = new StringBuffer();

        File file = new File("C:\Users\xxx\Desktop\abc.zip");
        InputStream input;

        try {
            input = new FileInputStream(file);
            ZipInputStream zip = new ZipInputStream(input);
            ZipEntry entry = zip.getNextEntry();

            Metadata metadata = new Metadata();
            Parser parser = new AutoDetectParser();

            while (entry != null) {
                if (entry.getName().endsWith(".txt") || entry.getName().endsWith(".pdf")
                        || entry.getName().endsWith(".docx")) {
                    System.out.println("entry=" + entry.getName() + " " + entry.getSize());
                    parser.parse(zip, new BodyContentHandlerFactory(BodyContentHandlerFactory.INCLUDE_ENTITY_ROOT,
                            false).getNewBodyContentHandler(), metadata, new ParseContext());
                    tempString.add(sbf.toString());
                }
                entry = zip.getNextEntry();
            }
            zip.close();
            input.close();

            for (String text : tempString) {
                System.out.println("Apache Tika - Converted input string : " + text);
                sbf.append(text);
                System.out.println("Final text from all the three files " + sbf.toString());
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (SAXException e) {
            e.printStackTrace();
        } catch (TikaException e) {
            e.printStackTrace();
        }
    }
}</code>

Note: It's important to modify the code to prevent the sbf being overwritten during each iteration and to clear it outside the loop to store the concated content from all files.

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