Exception sending context initialized event to listener instance of class Org.springframework.web.context.ContextLoaderListener

This time any of the configuration files are all handwritten 、、、 first handwriting, there is a problem and do not know where, but the exception is not imagined so much, but there is a seemingly I have not seen before the exception:

Exception sending context initialized event to listener instance of class Org.springframework.web.context.ContextLoaderListener org.springframework.beans.factory.BeanCreationException: Error creating Bean with Name ' Userdao ' defined in ServletContext resource [/web-inf/applicationcontext.xml]: Instantiati On Bean failed; Nested exception is java.lang.noclassdeffounderror:javax/xml/registry/infomodel/user caused by: Java.lang.noclassdeffounderror:javax/xml/registry/infomodel/user at Java.lang

Solutions are:

Download a Jaxr-api.jar import to the project exception disappears.

What is the specific role of this jar package on the Internet:

Sun's JAXR API

JAXR enables Java software programmers to access multiple XML registries using a single, easy-to-use abstraction API, a unified JAXR implementation model that describes the content and metadata in XML registries.

JAXR the ability of developers to write registry clients that can be used for multiple target registrations, and also to add value to these client programs across a variety of underlying registries.

The current version of the JAXR specification includes an exhaustive description of the bindings between the JAXR information model and the ebXML Registration specification. More information can be found at the following URL: http://java.sun.com/xml/downloads/jaxr.html

The service registration includes a JAXR provider with a Level 1 competency profile, which allows full access to the ebXML registration. The ebXML specification and JAXR specification are not well adapted because the ebXML specification is superior to the JAXR specification. Therefore, the JAXR provider for registration includes some additional implementation-specific methods that implement the ebXML specification, which may be included in the next version of the JAXR specification.

JAXR Architecture

The JAXR advanced structure consists of the following components:

JAXR client: This is a registered client program accessed using the JAXR API through the JAXR provider. This is a a client programs that uses the JAXR APIs to access a registry through a JAXR provider.
A JAXR provider: this is an implementation of the JAXR API that provides access to a particular registration provider or to a typical registration provider based on a common specification.

The JAXR provider implements two packages:

Javax.xml.registry, which consists of API interfaces and classes that define the registered access interface.
Javax.xml.registry.infomodel consists of interfaces that define the JAXR information model, which defines the types of objects residing in the registration and how they relate to each other. The basic interface in this package is the Registryobject interface.

The most basic interfaces in the Javax.xml.registry package are:

Connection. To represent a client to a session of a registered provider, for use of registration, the client must create a connection to the JAXR provider.
Registryservice. This is the Registryservice object that the client obtains from the connection, and through the Registryservice object, the client can sequentially gain access to the registered provider.