package com.aspose.slides.examples.Text;

import java.io.FileOutputStream;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Writer;

import com.aspose.slides.IAutoShape;
import com.aspose.slides.ISlide;
import com.aspose.slides.Presentation;
import com.aspose.slides.examples.Utils;

public class ExportingParagraphsTextToHTML {

	public static void main(String[] args) {

		// The path to the documents directory.
		String dataDir = Utils.getDataDir(ExportingParagraphsTextToHTML.class);

		// Load the presentation file
		Presentation pres = new Presentation(dataDir + "DemoFile.pptx");

		// Access the default first slide of presentation
		ISlide slide = pres.getSlides().get_Item(0);

		// Desired index
		int index = 0;

		// Accessing the added shape
		IAutoShape ashape = (IAutoShape) slide.getShapes().get_Item(index);

		try {
			// Creating output HTML file
			OutputStream os = new FileOutputStream(dataDir + "file.html");
			Writer writer = new OutputStreamWriter(os, "UTF-8");

			// Extracting first paragraph as HTML
			// Writing Paragraphs data to HTML by providing paragraph starting index, total paragraphs to be copied
			writer.write(ashape.getTextFrame().getParagraphs().exportToHtml(0, ashape.getTextFrame().getParagraphs().getCount(), null));
			writer.close();
		} catch (Exception fo) {
			fo.printStackTrace();

		}

	}

}

package com.aspose.slides.examples.Text;

import java.io.FileOutputStream;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Writer;

import com.aspose.slides.IAutoShape;
import com.aspose.slides.ISlide;
import com.aspose.slides.Presentation;
import com.aspose.slides.examples.Utils;

public class ExportingParagraphsTextToHTML {

	public static void main(String[] args) {

		// The path to the documents directory.
		String dataDir = Utils.getDataDir(ExportingParagraphsTextToHTML.class);

		// Load the presentation file
		Presentation pres = new Presentation(dataDir + "DemoFile.pptx");

		// Access the default first slide of presentation
		ISlide slide = pres.getSlides().get_Item(0);

		// Desired index
		int index = 0;

		// Accessing the added shape
		IAutoShape ashape = (IAutoShape) slide.getShapes().get_Item(index);

		try {
			// Creating output HTML file
			OutputStream os = new FileOutputStream(dataDir + "file.html");
			Writer writer = new OutputStreamWriter(os, "UTF-8");

			// Extracting first paragraph as HTML
			// Writing Paragraphs data to HTML by providing paragraph starting index, total paragraphs to be copied
			writer.write(ashape.getTextFrame().getParagraphs().exportToHtml(0, ashape.getTextFrame().getParagraphs().getCount(), null));
			writer.close();
		} catch (Exception fo) {
			fo.printStackTrace();
		}

	}

}

Update ExportingParagraphsTextToHTML.java