spring 2.0自定义xml 标记 (二 如何实现）

看了spring test 用例，其实实现这一功能还算比较简单，主要分以下的步骤，具体的实例可以去参考spring 自带的testcase

首先定义相关xsd文件，用于验证相应的行为：

主要增加了4个自定义元素和1个属性：

xmlns:xsd="http://www.w3.org/2001/XMLSchema"
targetNamespace="http://www.springframework.org/schema/beans/test"
elementFormDefault="qualified">

接着定义handler映射文件：customNamespace.properties

http\://www.springframework.org/schema/beans/test=org.springframework.beans.factory.xml.support.TestNamespaceHandler

定义Handler:

主要注册相应的解析类和装饰类

publicclass TestNamespaceHandler extends NamespaceHandlerSupport {

publicvoid init() {

//相对于每个xsd中定义的元素

registerBeanDefinitionParser("testBean", new TestBeanDefinitionParser());

registerBeanDefinitionDecorator("set", new PropertyModifyingBeanDefinitionDecorator());

registerBeanDefinitionDecorator("debug", new DebugBeanDefinitionDecorator());

registerBeanDefinitionDecorator("nop", new NopInterceptorBeanDefinitionDecorator());

registerBeanDefinitionDecoratorForAttribute("object-name", new ObjectNameBeanDefinitionDecorator());

}

}

定义各个解析类：

privatestaticclass TestBeanDefinitionParser implements BeanDefinitionParser {

public BeanDefinition parse(Element element, ParserContext parserContext) {

RootBeanDefinition definition = new RootBeanDefinition();

definition.setBeanClass(TestBean.class);

MutablePropertyValues mpvs = new MutablePropertyValues();

mpvs.addPropertyValue("name", element.getAttribute("name"));

mpvs.addPropertyValue("age", element.getAttribute("age"));

definition.setPropertyValues(mpvs);

parserContext.getRegistry().registerBeanDefinition(element.getAttribute("id"), definition);

returnnull;

}

}

privatestaticclassPropertyModifyingBeanDefinitionDecorator implements BeanDefinitionDecorator {

public BeanDefinitionHolder decorate(Node node, BeanDefinitionHolder definition,

ParserContext parserContext) {

Element element = (Element)node;

BeanDefinition def = definition.getBeanDefinition();

MutablePropertyValues mpvs = (def.getPropertyValues() == null) ?

new MutablePropertyValues() : def.getPropertyValues();

mpvs.addPropertyValue("name", element.getAttribute("name"));

mpvs.addPropertyValue("age", element.getAttribute("age"));

((AbstractBeanDefinition) def).setPropertyValues(mpvs);

return definition;

}

}

privatestaticclassDebugBeanDefinitionDecorator extends AbstractInterceptorDrivenBeanDefinitionDecorator {

protected BeanDefinition createInterceptorDefinition(Node node) {

returnnew RootBeanDefinition(DebugInterceptor.class);

}

}

privatestaticclassNopInterceptorBeanDefinitionDecorator extends

AbstractInterceptorDrivenBeanDefinitionDecorator {

protected BeanDefinition createInterceptorDefinition(Node node) {

returnnew RootBeanDefinition(NopInterceptor.class);

}

}

privatestaticclassObjectNameBeanDefinitionDecorator implements BeanDefinitionDecorator {

public BeanDefinitionHolder decorate(Node node, BeanDefinitionHolder definition,

ParserContext parserContext) {

Attr objectNameAttribute = (Attr)node;

definition.getBeanDefinition().setAttribute("objectName", objectNameAttribute.getValue());

return definition;

}

}

可以定义EntityResolver，用于验证相应的xsd

privateclass DummySchemaResolver extends PluggableSchemaResolver {

public DummySchemaResolver() {

super(CustomNamespaceHandlerTests.this.getClass().getClassLoader());

}

public InputSource resolveEntity(String publicId, String systemId) throws IOException {

InputSource source = super.resolveEntity(publicId, systemId);