Spring自定义标签

刺骨的言语ヽ痛彻心扉 2022-07-13 02:16 175阅读 0赞

# Spring自定义标签 #

Spring支持对自定义标签

--------------------

自定义spirng配置文件标签实现以下效果：

<?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:mrpc="http://blog.csdn.net/pretent/schema/mnm" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd http://blog.csdn.net/pretent/schema/mnm http://blog.csdn.net/pretent/schema/mnm.xsd">
    
        <mnm:annotation package="server.impl" />
    
    </beans>

## 定义约束文件xsd ##

需要在资源目录中/src/main/resources/META-INF/建立xsd文件

<xsd:schema xmlns="http://blog.csdn.net/pretent/schema/mnm" xmlns:xsd="http://www.w3.org/2001/XMLSchema" targetNamespace="http://blog.csdn.net/pretent/schema/mnm" elementFormDefault="qualified" attributeFormDefault="unqualified">
        <xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
    
        <xsd:element name="annotation">
            <xsd:complexType>
                <xsd:attribute name="package" type="xsd:string" />
            </xsd:complexType>
        </xsd:element>
    
    </xsd:schema>

## 指定XSD文件位置 ##

需要在资源目录中建立/src/main/resources/META-INF/**spring.schemas**文件

http\://blog.csdn.net/pretent/schema/mnm.xsd=META-INF/mnm.xsd

## 指定自定义标签处理程序 ##

需要在资源目录中建立/src/main/resources/META-INF/**spring.handlers**文件

http\://blog.csdn.net/pretent/schema/mnm=org.pretent.mrpc.support.handler.MnmNamespaceHandler

## 指定标签解析器 ##

org.pretent.mrpc.support.handler.MnmNamespaceHandler

package org.pretent.mrpc.support.handler;
    
    import org.pretent.mrpc.support.config.AnnotationConfig;
    import org.pretent.mrpc.support.parer.MnmBeanDefinitionParser;
    import org.springframework.beans.factory.xml.NamespaceHandlerSupport;
    
    public class MrpcNamespaceHandler extends NamespaceHandlerSupport { 
        public void init() {
            registerBeanDefinitionParser("annotation", new MnmBeanDefinitionParser(AnnotationConfig.class));
        }
    }

## 标签解析器 ##

org.pretent.mrpc.support.parer.MnmBeanDefinitionParser

package org.pretent.mrpc.support.parer;
    
    import org.pretent.mrpc.support.bean.ImplProxyBean;
    import org.pretent.mrpc.support.bean.RegisterBean;
    import org.pretent.mrpc.support.config.AnnotationConfig;
    import org.pretent.mrpc.support.config.ProtocolConfig;
    import org.pretent.mrpc.support.config.ReferenceConfig;
    import org.pretent.mrpc.support.config.ServiceConfig;
    import org.springframework.beans.factory.config.BeanDefinition;
    import org.springframework.beans.factory.support.RootBeanDefinition;
    import org.springframework.beans.factory.xml.BeanDefinitionParser;
    import org.springframework.beans.factory.xml.ParserContext;
    import org.w3c.dom.Element;
    
    /** * AbstractSingleBeanDefinitionParser * * @author pretent */
    public class MnmBeanDefinitionParserimplements BeanDefinitionParser {
    
        private Class<?> clazz;
    
        public MnmBeanDefinitionParser(Class<?> clazz) {
            this.clazz = clazz;
        }
    
        public BeanDefinition parse(Element element, ParserContext parserContext) {
            RootBeanDefinition beanDefinition = new RootBeanDefinition();
            beanDefinition.setLazyInit(false);
            String id = element.getAttribute("id");
            if (AnnotationConfig.class.equals(clazz)) {
                beanDefinition.setBeanClass(clazz);
                String packageName = element.getAttribute("package");
                beanDefinition.getPropertyValues().add("packageName", packageName);
            }
            if ((id == null || id.length() == 0)) {
                String name = element.getAttribute("name");
                if (name == null || name.length() == 0) {
                    name = clazz.getName();
                }
                id = name;
            }
            parserContext.getRegistry().registerBeanDefinition(id, beanDefinition);
            return beanDefinition;
        }
    }

org.pretent.mrpc.support.config.AnnotationConfig

package org.pretent.mrpc.support.config;
    
    public class AnnotationConfig {
    
        private String packageName;
    
        public String getPackageName() {
            return packageName;
        }
    
        public void setPackageName(String packageName) {
            this.packageName = packageName;
        }
    }

## 使用 ##

Spring 配置文件/src/main/resources/application.xml

<?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:mrpc="http://blog.csdn.net/pretent/schema/mnm" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd http://blog.csdn.net/pretent/schema/mnm http://blog.csdn.net/pretent/schema/mnm.xsd">
    
        <bean id="orderService" class="server.impl.OrderServiceImpl" />
    
        <mnm:annotation package="server.impl" />
    
    </beans>

这样就可以直接`<mnm:annotation package="server.impl" />` 把解析成一个AnnotationConfig 类型的bean对象了。