基于Spring可扩展Schema自定义配置

Posted 2020-06-09 大扑棱蛾子

本章主要实现配置支持，注解扫描等功能。为本次教程的核心

命名空间支持

要实现命名空间支持，需要继承自NamespaceHandlerSupport。

package com.codestd.spring.cxf.config.schema;

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

import com.codestd.spring.cxf.config.EndpointBeanProcessor;
/**
 * 处理命名空间
 * @author jaune(Wang Chengwei)
 * @since 1.0.0
 */
public class WebServiceAnnotationNamespaceHandler extends NamespaceHandlerSupport {

    @Override
    public void init() {
        // TODO Auto-generated method stub
        this.registerBeanDefinitionParser("annotation-endpoint", new AnnotationBeanDefinitionParser(EndpointBeanProcessor.class));
    }

}

通过registerBeanDefinitionParser方法讲配置支持添加到Spring中。annotation-endpoint是配置支持的元素。AnnotationBeanDefinitionParser是处理配置的类。EndpointBeanProcessor是处理@Endpoint注解的Bean的类，后面会有详细的讲述。

处理配置

需要实现BeanDefinitionParser

package com.codestd.spring.cxf.config.schema;

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.springframework.util.StringUtils;
import org.w3c.dom.Element;

/**
 * @author jaune(Wang Chengwei)
 * @since 1.0.0
 */
public class AnnotationBeanDefinitionParser implements BeanDefinitionParser {

    private final Class<?> beanClass;

    public AnnotationBeanDefinitionParser(Class<?> beanClass) {
        this.beanClass = beanClass;
    }

    @Override
    public BeanDefinition parse(Element element, ParserContext parserContext) {
        RootBeanDefinition beanDefinition = new RootBeanDefinition();
        beanDefinition.setBeanClass(beanClass);
        beanDefinition.setLazyInit(false);

        String id = element.getAttribute("id");
        if(id == null || id.length() == 0 ){
            String name = element.getAttribute("name");
            if(!StringUtils.isEmpty(name)) id = name;
            else id = beanClass.getName();
        }

        if (parserContext.getRegistry().containsBeanDefinition(id))  {
            throw new IllegalStateException("Duplicate spring bean id " + id);
        }
        parserContext.getRegistry().registerBeanDefinition(id, beanDefinition);

        String annotationPackage = element.getAttribute("package");
        if(!StringUtils.isEmpty(annotationPackage))
            beanDefinition.getPropertyValues().add("annotationPackage", annotationPackage);

        return beanDefinition;
    }
}

BeanDefinitionParser的应用参见Spring官方文档。

Bean注册工具类

package com.codestd.spring.cxf.config;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.support.BeanDefinitionBuilder;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.ConfigurableApplicationContext;

/**
 * Registry Bean. Must inject the spring ApplicationContext.
 * @author jaune(Wang Chengwei)
 * @since 1.0.0
 */
public class BeanRegistry implements ApplicationContextAware{

    private ApplicationContext applicationContext;

    private ConfigurableApplicationContext configurableApplicationContext;

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        this.applicationContext = applicationContext;
        if(applicationContext instanceof ConfigurableApplicationContext){
            this.configurableApplicationContext = (ConfigurableApplicationContext)this.applicationContext;
        }
    }

    public BeanRegistry(){

    }

    public BeanRegistry(ApplicationContext applicationContext){
        this.setApplicationContext(applicationContext);
    }

    public BeanDefinition register(Class<?> clazz){
        if(configurableApplicationContext == null)return null;
        BeanDefinitionRegistry beanDefinitonRegistry = 
                (BeanDefinitionRegistry)configurableApplicationContext.getBeanFactory();

        BeanDefinitionBuilder beanDefinitionBuilder = this.createBuilder(clazz);
        BeanDefinition beanDefinition = beanDefinitionBuilder.getRawBeanDefinition();
        beanDefinitonRegistry.registerBeanDefinition(clazz.getName(),beanDefinition);

        return beanDefinition;
    }

    private BeanDefinitionBuilder createBuilder(Class<?> clazz){
        BeanDefinitionBuilder beanDefinitionBuilder = BeanDefinitionBuilder.genericBeanDefinition(clazz);
        return beanDefinitionBuilder;
    }

}

处理@Endpoint

package com.codestd.spring.cxf.config;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
import org.springframework.beans.factory.config.BeanPostProcessor;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.annotation.ClassPathBeanDefinitionScanner;
import org.springframework.core.type.filter.AnnotationTypeFilter;
import org.springframework.util.StringUtils;

import com.codestd.spring.cxf.annotation.Endpoint;

/**
 * @author jaune(WangChengwei)
 * @since 1.0.0
 */
public class EndpointBeanProcessor implements 
    BeanFactoryPostProcessor, DisposableBean, BeanPostProcessor, ApplicationContextAware{

    private final String COMMA_SPLIT_PATTERN = ",";

    private ApplicationContext applicationContext;

    private String annotationPackage;

    private String[] annotationPackages;

    private BeanRegistry beanRegistry;

    public void setAnnotationPackage(String annotationPackage) {
        this.annotationPackage = annotationPackage;
        if(!StringUtils.isEmpty(this.annotationPackage))
            this.annotationPackages = this.annotationPackage.split(this.COMMA_SPLIT_PATTERN);
    }

    @Override
    public void setApplicationContext(ApplicationContext applicationContext)
            throws BeansException {
        this.applicationContext = applicationContext;
        this.beanRegistry = new BeanRegistry(this.applicationContext);
    }

    @Override
    public Object postProcessAfterInitialization(Object bean, String beanName)
            throws BeansException {

        if(!this.isMatchPackage(bean))return bean;

        Endpoint endpoint = bean.getClass().getAnnotation(Endpoint.class);
        if(endpoint != null){
            System.out.println(bean.getClass());
        }

        return bean;
    }

    @Override
    public Object postProcessBeforeInitialization(Object bean, String beanName)
            throws BeansException {
        return bean;
    }

    @Override
    public void destroy() throws Exception {

    }

    /**
     * 包是否匹配
     * @param bean
     * @return
     */
    private boolean isMatchPackage(Object bean){
        if (annotationPackages == null || annotationPackages.length == 0) {
            return true;
        }
        String beanClassName = bean.getClass().getName();
        for (String pkg : annotationPackages) {
            if (beanClassName.startsWith(pkg)) {
                return true;
            }
        }
        return false;
    }


    /**
     * 扫描{@link com.codestd.spring.cxf.annotation.Endpoint}注解
     */
    @Override
    public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
        if (annotationPackage == null || annotationPackage.length() == 0) {
            return;
        }

        if (beanFactory instanceof BeanDefinitionRegistry) {
            BeanDefinitionRegistry beanDefinitionRegistry = (BeanDefinitionRegistry)beanFactory;
            ClassPathBeanDefinitionScanner scanner = new ClassPathBeanDefinitionScanner(beanDefinitionRegistry,true);

            AnnotationTypeFilter filter = new AnnotationTypeFilter(Endpoint.class);
            scanner.addIncludeFilter(filter);

            scanner.scan(annotationPackages);
        }
    }

}

这里已经实现了注解的扫描。然后需要在postProcessAfterInitialization方法中写业务处理代码。AfterInitialization表示Bean已经创建并且注入属性。
postProcessBeforeInitialization主要是为了在Bean实例化时注入属性。

让Spring识别扩展

首先在classpath的META-INF下创建spring.handlers，内容如下

http\://www.codestd.com/schema/std/ws=com.codestd.spring.cxf.config.schema.WebServiceAnnotationNamespaceHandler

在这个文件中指明了哪个命名空间需要哪个类来处理。
然后再创建spring.schemas

http\://www.codestd.com/schema/std/ws/stdws-1.0.xsd=META-INF/schema/stdws-1.0.xsd

指明了Sechma文件的位置，Spring会使用这里制定的xsd文件来验证配置是否正确。

测试

创建接口

package com.codestd.spring.cxf.ws;

import javax.jws.WebService;

/**
 * @author jaune(Wang Chengwei)
 * @since 1.0.0
 */
@WebService
public interface HelloService {

    public String syHi(String name);
}

实现类

package com.codestd.spring.cxf.ws;

import javax.jws.WebService;

import com.codestd.spring.cxf.annotation.Endpoint;

/**
 * @author jaune(Wang Chengwei)
 * @since 1.0.0
 */
@Endpoint(address="HelloService", id = "HelloServiceEndpoint")
@WebService(endpointInterface="com.codestd.spring.cxf.ws.HelloService")
public class HelloServiceImpl implements HelloService{

    @Override
    public String syHi(String name) {
        return "Hello "+name;
    }

}

测试用例

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations={"classpath:applicationContext.xml"})
public class InitializationTest {

    @Test
    public void test(){

    }

}

在处理类中有一段代码是将有@Endpoint注解的类都打印出来，所以如果类名被打印出来就表示配置正常了。
运行测试用例
控制台能够看到

class com.codestd.spring.cxf.ws.HelloServiceImpl

本次扩展基本实现。

本此教程的内容可以在Spring官方文档第42章中找到。

Note
本次并没有实现自动发布WebService的功能，这块儿功能比较复杂暂时还没有实现，如果实现会在后面的博文中补充。