spring schema 扩展-优快云博客

本文链接：https://blog.youkuaiyun.com/iteye_8889/article/details/81967052

本文介绍如何使用Spring基于自定义的XML Schema定义新的bean类型。通过创建自定义的xsd文件和对应的处理器，实现了一个日期格式化的bean，并在Spring上下文中进行配置及验证。

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spring 可以基于schema 扩展，自定义 schema。参考文档自己搭了个应用试验了一下：

首先看下自己写的 myns.xsd

<?xml version="1.0" encoding="UTF-8"?>
<xsd:schema xmlns="http://www.yjhexy.com/schema/myns"
	xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:beans="http://www.springframework.org/schema/beans"
	targetNamespace="http://www.yjhexy.com/schema/myns" elementFormDefault="qualified"
	attributeFormDefault="unqualified">

	<xsd:import namespace="http://www.springframework.org/schema/beans" />

	<xsd:element name="dateformat">
		<xsd:complexType>
			<xsd:complexContent>
				<xsd:extension base="beans:identifiedType">
					<xsd:attribute name="lenient" type="xsd:boolean" />
					<xsd:attribute name="pattern" type="xsd:string" use="required" />
				</xsd:extension>
			</xsd:complexContent>
		</xsd:complexType>
	</xsd:element>

</xsd:schema>

然后看下我的applicationContxt.xml配置:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:myns="http://www.yjhexy.com/schema/myns"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
	http://www.yjhexy.com/schema/myns http://www.yjhexy.com/schema/myns/myns.xsd
	">

	<myns:dateformat id="dateFormat" pattern="yyyy-MM-dd HH:mm"
		lenient="true" />

</beans>

很明显实现了个自定义的bean ,这个bean有两个属性，一个是时间的格式，另外一个不知道啥东西。

然后在META-INF下面写了两个文件，

spring.handlers:用来描述如何处理自定义的namespace

http\://www.yjhexy.com/schema/myns=com.yajun.balance.spring.MyNamespaceHandler

spring.schemas:描述schema的位置

http\://www.yjhexy.com/schema/myns/myns.xsd=com/yajun/balance/spring/myns.xsd

然后是需要两个类，一个处理namespace,一个处理beanDefinition

package com.yajun.balance.spring;

import org.springframework.beans.factory.xml.NamespaceHandlerSupport;

public class MyNamespaceHandler extends NamespaceHandlerSupport {

    public void init() {
        registerBeanDefinitionParser("dateformat", new SimpleDateFormatBeanDefinitionParser());
    }

}

package com.yajun.balance.spring;

import java.text.SimpleDateFormat;

import org.springframework.beans.factory.support.BeanDefinitionBuilder;
import org.springframework.beans.factory.xml.AbstractSingleBeanDefinitionParser;
import org.springframework.util.StringUtils;
import org.w3c.dom.Element;

public class SimpleDateFormatBeanDefinitionParser extends AbstractSingleBeanDefinitionParser {

    protected Class getBeanClass(Element element) {
        return SimpleDateFormat.class;
    }

    protected void doParse(Element element, BeanDefinitionBuilder bean) {
        // this will never be null since the schema explicitly requires that a value be supplied
        String pattern = element.getAttribute("pattern");
        bean.addConstructorArgValue(pattern);

        // this however is an optional property
        String lenient = element.getAttribute("lenient");
        if (StringUtils.hasText(lenient)) {
            bean.addPropertyValue("lenient", Boolean.valueOf(lenient));
        }
    }
}

最后main输出试试：

package com.yajun.balance.spring;

import java.text.SimpleDateFormat;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class MainTest {

    public static void main(String[] args) {
        ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
        SimpleDateFormat f = (SimpleDateFormat) ctx.getBean("dateFormat");
        System.out.println(f);
    }
}

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xsd 基础常用的简单类型