What You Should Know About Java XML
XML is a format that has become an important part of information technology. In addition to this, the combination of Java and XML have become very important for those who work with back end business components.
Combining Java with XML has allowed developers to save a large amount of time and energy in the creation of new programs. If this technology is used correctly it will make your applications more flexible and ready for change. Another thing that you will want to become familiar with is XStream.
Before I talk about how XStream can serialize Java elements, it is first important to understand how Java XML binding is separate from Java XML serialization. These technologies are similar in the fact that they can transfer XML objects into Java objects and vice versa. At the same time, Java XML binding shows a step that will create basic Java code from XML schemas. A large number of binding libraries are very efficient, and an example of this would be JAXB by Sun. Java XML serialization uses a runtime conversion that is dependent on the API to transfer a Java object into an XML object. Libraries like XStream will use powerful APIs to control how XML objects are produced to make sure they can be read.
Serialization is easier because there is no need to create the necessary source code. However, the disadvantage to serialization is that is that there will be no way to make sure the XML source will properly deserialize if it is not created within the same library. To use Java XML with XStream, you will need to have Java 1.4 or newer, and you will also need to have the XStream serialization library. The xstream-1.1.2.jar file is very important. You will also need to have basic to intermediate skills with both Java and XML. Xstream is controlled by a large team of highly skilled programmers.
Even though XStream can be defined as a serialization library, the classes that you serialize won’t need to show the serialized marker. XStream works by using the internal fields of an object, and these fields will be handled by a converter. If you use a solution that is dependent on the reflection, there could be problems with performance. However, it should be noted that the library is generally fast. If this is your first time working with the combination of Java and XML, you will need to know that changing the characteristics of a class or techniques after you’ve serialized the class can place the deserialization of the object at risk.
The programmers who created Xstream tried to make sure the program could properly deal with situations where the class is altered. It only takes three lines of code in order to serialize or undo an object which has been serialized. You will want to make sure your XML is correct, because XStream will not give you any confirmation. The code below was taken from the Xstream website, and this is a high quality XML library. You may need to adjust it to suit your needs:
//Convert a Java object to XML
XStream xstream = new XStream();
XStream xstream = new XStream(new DomDriver()); // does not require XPP3 library
String xml = xstream.toXML(joe);
//Convert XML to a Java object using the
//same xstream reference
Person joe = xstream.fromXML(joeXML); //joeXML not shown
While XStream has a number of good features, it does have some problems. If you are using a JDK version which is older than 1.4, you will need to use a no-arg default constructor. This is important when you want to deserialize an object. Using an updated version of JDK can help you avoid this additional step. When you work with XML, it is important to make sure your information can be read. This is extremely important. It is also important for you to understand the design of Xstream. You may notice in the sample code that Xstream can serialize object graphs which are nested.
Xstream has designed its XML by using a number of conversion classes that can deal with the many basic Java elements you will run into. This includes many collection classes. Converters play an important role with Xstream, and it is best to look at their reference guide before you begin work on a project. Having an idea of how XML looks will make things easier to understand.
