O/X mapping概念及JAXB简介

Object/XML Mapping (O/X mapping)指XML文档与Java对象之间的映射关系。

XML Marshalling（也称为XML Serialization）是指在XML文档与Java对象之间的转换过程。

将Java对象转换为XML文档，称为marshaller 。

将XML文档转换为Java对象，称为unmarshaller 。

常见的O/Xmapping API：

• JAXB
• XMLBeans
• JiBX
• Castor
• XStream

JAXB specification provides a way to map Java classes to XMLrepresentations，是JCP的标准之一：

• JAXB 1.0，JSR-31
• JAXB 2.0/2.1/2.2，JSR-222

JAXB RI是JAXB规范的实现。JAXB project的主要目的就是开发并维护JAXB RI，当前最新版是2014.10发布的JAXB RI 2.2.11。

此外，JAXB project还提供了如下扩展工具：

• Jsonix - JAXB analog for JavaScript
• Hyperjaxb3 - relational persistence for JAXB objects with JPA (Hibernate,TopLink etc.)
• XJCplugins - variousenhancements to XJC developed by the community
• MavenJAXB2 Plugin - actualMaven plugin for JAXB2
• JAXB2reflection library
• JAXBIntroductions - put JAXBannotations on 3rd party classes
• Annox - allows defining JAXB annotations in XML resources
• JAXB Workshop, Eclipse Plugins

 

从JDK6开始，JavaArchitecture for XML Binding (JAXB) 成为JDK的组成部分：

• JAXB RI 2.0.3 in JDK 6 first release - JDK6 u3
• JAXB 2.0 in JavaEE 5
• JAXB RI 2.1.3 in JDK 6 u4
• JAXB RI 2.1.10 in JDK 6 u14
• JAXB RI 2.2.4-1 in JDK 7 first release
• JAXB 2.2.4 in JavaEE 6 
• JAXB RI 2.2.4-2 in JDK 7 u6
• JAXB 2.2.11 in JDK 8 
• JAXB 2.2.11 in JavaEE 7 

  

two features of JAXB:

• to marshal Java objects into XML
• to unmarshal XML back into Java objects

 

1.     XML Schema -> Java class

JAXB provides“xjc” tool to convert XML Schema to class representations.

JAXB bindingcompiler xjc is also part of the JDK6,it is a command line tool which can beused togenerate binding classes basedon an existing XSD schema description.

 

2.      Javaclass -> XML Schema

JAXB includes a“schemagen” tool which can create an XML Schema from a set of annotatedclasses.

 

参考文献：

JAXB project官网https://jaxb.java.net/