OpenOffice.org is quite nice as a free and open source office suite that works on Linux and Windows and I use it quite a lot.

Besides its use as a desktop application it is not widely recognized that it can also be used as a backend document processing system by your Java application. Use cases are numerous: an invocice generating webapp in your intranet, prefilled document templates with content from a database or just an online inventory of your documents wiht support for on demand conversion to Microsoft Office formats or PDF.

The key to make your Java applications talk to OpenOffice is called UNO. UNO stands for Universal Network Objects and is the remoting system used by OpenOffice. It's a bit like CORBA.

First to enable remoting you must start OpenOffice with the -accept option:

/usr/bin/ooffice -accept="socket,host=0,port=8200,tcpNoDelay=1;urp;" -nologo

Source: Professional UNO

You can also add the -headless option which allows using the application without user interface.

There is not much introducory documentation besides the heavy-weight Developers Guide and a blog entry from 2005.

You need a few jars that you can either download as part of the SDK from the OpenOffice.org website. If you are using Maven you can instead just add the following dependencies to your pom.xml:

<dependency>
        <groupId>org.openoffice</groupId>
        <artifactId>juh</artifactId>
        <version>2.1.0</version>
        <scope>compile</scope>
</dependency>
<dependency>
        <groupId>org.openoffice</groupId>
        <artifactId>jurt</artifactId>
        <version>2.1.0</version>
        <scope>compile</scope>
</dependency>
<dependency>
        <groupId>org.openoffice</groupId>
        <artifactId>ridl</artifactId>
        <version>2.1.0</version>
        <scope>compile</scope>
</dependency>
<dependency>
        <groupId>org.openoffice</groupId>
        <artifactId>unoil</artifactId>
        <version>2.1.0</version>
        <scope>compile</scope>
</dependency>

You need some boilerplate code to connect to OpenOffice:

Object x;
Object defaultContext;
Object desktop;

XComponentContext componentContext = Bootstrap.createInitialComponentContext(null);
x = componentContext.getServiceManager().createInstanceWithContext("com.sun.star.connection.Connector", componentContext);
XConnector connector = (XConnector) UnoRuntime.queryInterface(XConnector.class, x);
XConnection connection = connector.connect(getConnectionString());

x = componentContext.getServiceManager().createInstanceWithContext("com.sun.star.bridge.BridgeFactory", componentContext);
XBridgeFactory bridgeFactory = (XBridgeFactory) UnoRuntime.queryInterface(XBridgeFactory.class, x);
bridge = bridgeFactory.createBridge("", "urp", connection, null);

x = bridge.getInstance("StarOffice.ServiceManager");
XMultiComponentFactory multiComponentFactory = (XMultiComponentFactory) UnoRuntime.queryInterface(XMultiComponentFactory.class, x);

XPropertySet properySet = (XPropertySet) UnoRuntime.queryInterface(XPropertySet.class, multiComponentFactory);
defaultContext = properySet.getPropertyValue("DefaultContext");
componentContext = (XComponentContext) UnoRuntime.queryInterface(XComponentContext.class, defaultContext);
multiComponentFactory = componentContext.getServiceManager();

desktop = multiComponentFactory.createInstanceWithContext("com.sun.star.frame.Desktop", componentContext);
componentLoader = (XComponentLoader) UnoRuntime.queryInterface(XComponentLoader.class, desktop);
multiServiceFactory = (XMultiServiceFactory) UnoRuntime.queryInterface(XMultiServiceFactory.class, multiComponentFactory);

Now you have a XComponentLoader that you can use to load additional resources like a document:

// Load the document, which will be displayed.
XComponent xComponent = openOfficeConnection.getComponentLoader().loadComponentFromURL(
    "test.odt", "_blank", 0, new PropertyValue[0]);
// Get the textdocument
XTextDocument aTextDocument = (XTextDocument) UnoRuntime.queryInterface(XTextDocument.class, xComponent);

If you didn't run OpenOffice in headless mode you'll see the document on your screen now. Let's have a look at some simple operations on that document:

XTextDocument xtd = (XTextDocument) UnoRuntime.queryInterface(XTextDocument.class, xComponent);
XDocumentInfoSupplier xdis = (XDocumentInfoSupplier) UnoRuntime.queryInterface(XDocumentInfoSupplier.class, xtd);
XDocumentInfo xdi = xdis.getDocumentInfo();
XPropertySet xps = (XPropertySet) UnoRuntime.queryInterface(XPropertySet.class, xdi);
XPropertySetInfo xpsi = xps.getPropertySetInfo();

XFastPropertySet xfps = (XFastPropertySet) UnoRuntime.queryInterface(XFastPropertySet.class, xps);

for (Property property : xpsi.getProperties())
{
    String name = property.Name;
    Object value = xfps.getFastPropertyValue(property.Handle);

    System.out.println(name + ": " + value);
}

This code snippet prints the meta information of the document (what you get if you choose File/Properties...) to stdout.

Of course you can do much more, querying for tables in the document, changing or adding text, saving the document to different formats like Microsoft Word or PDF. Have a look at the javadocs and the IDL reference at http://api.openoffice.org/ and play with it.

Responses[11]

Posted by Stefan Reuter on February 25, 2007 12:21:06 PM CET #