How to read or parse MHTML (.mht) files in java

Question

I need to mine the content of most of known document files like:

1. pdf
2. html
3. doc/docx etc.

For most of these file formats I am planning to use:

http://tika.apache.org/

But as of now Tika does not support MHTML (*.mht) files.. ( http://en.wikipedia.org/wiki/MHTML ) There are few examples in C# ( http://www.codeproject.com/KB/files/MhtBuilder.aspx ) but I found none in Java.

I tried opening the *.mht file in 7Zip and it failed...Although the WinZip was able to decompress the file into images and text (CSS, HTML, Script) as text and binary files...

As per MSDN page ( http://msdn.microsoft.com/en-us/library/aa767785%28VS.85%29.aspx#compress_content ) and the code project page i mentioned earlier ... mht files use GZip compression ....

Attempting to decompress in java results in following exceptions: With java.uti.zip.GZIPInputStream

java.io.IOException: Not in GZIP format
at java.util.zip.GZIPInputStream.readHeader(Unknown Source)
at java.util.zip.GZIPInputStream.<init>(Unknown Source)
at java.util.zip.GZIPInputStream.<init>(Unknown Source)
at GZipTest.main(GZipTest.java:16)

And with java.util.zip.ZipFile

 java.util.zip.ZipException: error in opening zip file
at java.util.zip.ZipFile.open(Native Method)
at java.util.zip.ZipFile.<init>(Unknown Source)
at java.util.zip.ZipFile.<init>(Unknown Source)
at GZipTest.main(GZipTest.java:21)

Kindly suggest how to decompress it....

Thanks....

Answer 1

A more compact code using Java Mail APIs

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.net.URL;
import java.util.Properties;

import javax.mail.BodyPart;
import javax.mail.Session;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMultipart;

import org.apache.commons.io.IOUtils;

public class MhtParser {

    private File mhtFile;
    private File outputFolder;

    public MhtParser(File mhtFile, File outputFolder) {
        this.mhtFile = mhtFile;
        this.outputFolder = outputFolder;
    }

    public void decompress() throws Exception {
        MimeMessage message = 
            new MimeMessage(
                    Session.getDefaultInstance(new Properties(), null),
                    new FileInputStream(mhtFile));

        if (message.getContent() instanceof MimeMultipart) {
            outputFolder.mkdir();
            MimeMultipart mimeMultipart = (MimeMultipart) message.getContent();

            for (int i = 0; i < mimeMultipart.getCount(); i++) {
                BodyPart bodyPart = mimeMultipart.getBodyPart(i);
                String fileName = bodyPart.getFileName();

                if (fileName == null) {
                    String[] locationHeader = bodyPart.getHeader("Content-Location");
                    if (locationHeader != null && locationHeader.length > 0) {
                        fileName = 
                            new File(new URL(locationHeader[0]).getFile()).getName();
                    }
                }

                if (fileName != null) {
                    FileOutputStream out = 
                        new FileOutputStream(new File(outputFolder, fileName));

                    IOUtils.copy(bodyPart.getInputStream(), out);
                    out.flush();
                    out.close();
                }
            }
        }
    }
}

Answer 2

You don't have to do it on you own.

With dependency

<dependency>
    <groupId>org.apache.james</groupId>
    <artifactId>apache-mime4j</artifactId>
    <version>0.7.2</version>
</dependency>

Roll you mht file

public static void main(String[] args)
{
    MessageTree.main(new String[]{"YOU MHT FILE PATH"});
}

MessageTree will

/**
 * Displays a parsed Message in a window. The window will be divided into
 * two panels. The left panel displays the Message tree. Clicking on a
 * node in the tree shows information on that node in the right panel.
 *
 * Some of this code have been copied from the Java tutorial's JTree section.
 */

Then you can look into it.

;-)