Spring oxm getting started instance

What is an O / xmapper?

Spring3. A new feature of 0 is O / xmapper. The concept of O / X mapper is not new. O represents object and X represents XML. Its purpose is to convert back and forth between a Java object (almost always a plain old Java object, or POJO) and an XML document.

For example, you might have a simple bean with several properties, and your business needs to convert that Java object into an XML document. Spring's O / X mapper can solve that problem for you. If, conversely, you need to convert an XML document into a simple java bean, spring's O / xmapper is also competent.

One thing to note: Spring O / xmapper just defines a unified interface implemented by popular third-party frameworks. To take advantage of spring's O / X capabilities, you need a utility that converts Java objects and XML back and forth. Castor is such a popular third-party tool that this article will use. Other such tools include xmlbeans, Java architecture for xmlbinding (JAXB), jibx, and xStream.

Group and ungroup

When doing O / X mapping, you often see the terms marshalling and unmarshalling.

Marshalling refers to the process of converting a java bean into an XML document, which means that all fields and field values of a java bean will be filled into the XML file as XML elements or attributes. Sometimes, marshalling is also called serializing.

As you might expect, unmarshalling is the exact opposite of marshalling, that is, converting an XML document into a java bean, which means that all elements or attributes of the XML document are filled into the java bean as Java fields. Sometimes, unmarshalling is also called deserializing.

Benefits of using spring's O / xmapper

One of the most direct benefits of using spring's O / X mapper is that configuration can be simplified by taking advantage of other features of the spring framework. Spring's bean library supports the injection of instantiated O / X marshallers (i.e. "dependency injection" mentioned earlier) using the objects of those marshallers. Again, this will speed up application development and deployment.

Following solid object-oriented design practices, the spring O / X framework defines only two interfaces: Marshall and unmarshaller, which are used to perform O / X functions, which is another major benefit of using this framework. The implementation of these interfaces is completely open to independent developers, who can easily switch them without modifying the code. For example, if you start with castor for O / X conversion, but later find that it lacks a function you need, you can switch to xmlbeans without any code changes. The only thing you need to do is change the spring configuration file to use the new O / X framework.

Another benefit of using spring's O / xmapper is a unified exception hierarchy. The spring framework follows the pattern established using its data access module by wrapping the original exception object into spring's own run-time exception built specifically for O / xmapper. Since the original exception thrown by the third-party provider is wrapped in the spring runtime exception, you can find out the root cause of the exception. You also don't have to bother modifying the code to catch exceptions, because exceptions are wrapped in a runtime exception. The following runtime exceptions extend the underlying exception xmlmappingexception: genericmarshallingfailureexception, validationfailureexception, marshalingfailureexception, and unmarshallingfailureexception.

Introduction chestnut

Configuration list:

applicationContext. Xmlspring configuration file

During grouping and ungrouping, the mapping format applied must be used for ungrouping to succeed (there is a doubt here. I don't know whether it is because of my own writing problem, I can only ungroup through mapping format coding, otherwise an error that cannot find the rootelement will be reported).

mapping. XML file

Custom bean file

Customer. java

xmlDemo. Java file

test

Test results:

summary

The above is all about the spring oxm entry example in this article. I hope it will be helpful to you. Interested friends can continue to refer to other related topics on this site. If there are deficiencies, please leave a message to point out. Thank you for your support!