spring 拾遗 0x00 如何在spring xml配置中使用自己的schema

如果我想在spring中使用下面一段自定义配置来实例化一个池

<donar:pool poolSize="50" name="mypool" id="mypool"/>

那么需要如下几步

Step 1 定义 xsd

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"
            xmlns:beans="http://www.springframework.org/schema/beans"
            xmlns:tool="http://www.springframework.org/schema/tool"
            xmlns="http://code.raycloud.com/schema/donar"
            targetNamespace="http://code.raycloud.com/schema/donar"> <!--这里是命名空间-->
    <xsd:import namespace="http://www.springframework.org/schema/beans" />
    <xsd:import namespace="http://www.springframework.org/schema/tool" />


    <xsd:element name="pool">
        <xsd:complexType>
            <xsd:complexContent>
                <xsd:extension base="beans:identifiedType">
                    <xsd:attribute name="name" type="xsd:string">
                        <xsd:annotation>
                            <xsd:documentation>名称</xsd:documentation>
                        </xsd:annotation>
                    </xsd:attribute>
                    <xsd:attribute name="poolSize" type="xsd:int">
                        <xsd:annotation>
                            <xsd:documentation>池大小</xsd:documentation>
                        </xsd:annotation>
                    </xsd:attribute>
                </xsd:extension>
            </xsd:complexContent>
        </xsd:complexType>
    </xsd:element>
</xsd:schema>

Step 2 解析xml配置

• 定义命名空间处理类

package com.donar.spring;

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

/**
 * Created by donar on 17/11/27.
 * 命名空间处理类  继承NamespaceHandlerSupport 在init方法中注册 pool 元素的解析类
 */
public class DonarNameSpaceHandler extends NamespaceHandlerSupport{
    @Override
    public void init() {
        registerBeanDefinitionParser("pool",new PoolBeanDefinitionParser());
    }
}

• 解析类

package com.donar.spring.bean;

/**
 * Created by donar on 17/11/27.
 */
public class Pool {
    Integer poolSize;
    String name;

    public Integer getPoolSize() {
        return poolSize;
    }

    public void setPoolSize(Integer poolSize) {
        this.poolSize = poolSize;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

package com.donar.spring;

import com.donar.spring.bean.Pool;
import org.springframework.beans.factory.support.BeanDefinitionBuilder;
import org.springframework.beans.factory.xml.AbstractSingleBeanDefinitionParser;
import org.w3c.dom.Element;

/**
 * Created by donar on 17/11/27.
 */
public class PoolBeanDefinitionParser extends AbstractSingleBeanDefinitionParser{
    @Override
    protected Class<?> getBeanClass(Element element) {
        return Pool.class;
    }

    @Override
    protected void doParse(Element element, BeanDefinitionBuilder builder) {
        String name = element.getAttribute("name");
        Integer size = Integer.valueOf(element.getAttribute("poolSize"));
        builder.addPropertyValue("name",name);
        builder.addPropertyValue("poolSize",size);
    }
}

Step 3 添加spring资源文件

• spring.handler 用来配置解析命名空间时对应的处理类
  http\://code.raycloud.com/schema/donar=com.donar.spring.DonarNameSpaceHandler
• spring.schemas
  http\://code.raycloud.com/schema/donar/donar.xsd=META-INF/donar.xsd

---

完成这几步后我们在spring中配置中引用我们的xsd文件 就可以在spring加载bean的时候把我们自己命名空间的标签也纳入其中了

<?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:donar="http://code.raycloud.com/schema/donar"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
    http://code.raycloud.com/schema/donar
    http://code.raycloud.com/schema/donar/donar.xsd">

    <donar:pool poolSize="50" name="mypool" id="mypool"/>
      
</beans>

import com.donar.spring.bean.Pool;
import org.junit.Test;
import org.springframework.context.support.ClassPathXmlApplicationContext;

/**
 * Created by donar on 17/11/27.
 */
public class TestSpringSchema {
    @Test
    public void test(){
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("classpath:applicationContext.xml");
        Pool pool = (Pool) context.getBean("mypool");
        System.out.println(pool.getName() + "---" + pool.getPoolSize());
    }
}

输出结果

mypool---50