动态加载 bean 到Spring Context-优快云博客

本文介绍了一种使用Spring框架动态加载Bean的方法。通过实现ApplicationContextAware接口并覆盖setApplicationContext方法，可以在运行时向Spring容器中添加新的Bean定义。示例代码展示了如何配置和使用DynamicLoadBean类来实现这一功能。

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[b]动态Bean的实现类[/b]



import java.io.IOException;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.xml.ResourceEntityResolver;
import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.ConfigurableApplicationContext;

/**
 * 
 * This class used to dynamic loan bean to spring context during runtime
 * 
 *
 */
public class DynamicLoadBean implements ApplicationContextAware{

	private ConfigurableApplicationContext applicationContext = null;
	public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
		this.applicationContext = (ConfigurableApplicationContext)applicationContext;
	}
	public ConfigurableApplicationContext getApplicationContext() {
		return applicationContext;
	}

	/**
	 * 向spring的beanFactory动态地装载bean
	 * @param configLocationString 要装载的bean所在的xml配置文件位置。
spring配置中的contextConfigLocation，同样支持诸如"/WEB-INF/ApplicationContext-*.xml"的写法。
	 */
	public void loadBean(String configLocationString){
		XmlBeanDefinitionReader beanDefinitionReader = new XmlBeanDefinitionReader((BeanDefinitionRegistry)getApplicationContext().getBeanFactory());
		beanDefinitionReader.setResourceLoader(getApplicationContext());
		beanDefinitionReader.setEntityResolver(new ResourceEntityResolver(getApplicationContext()));
		try {
			String[] configLocations = new String[]{configLocationString};
			for(int i=0;i<configLocations.length;i++)
				beanDefinitionReader.loadBeanDefinitions(getApplicationContext().getResources(configLocations[i]));
		} catch (BeansException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
}

[b]测试类如下[/b]


        ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext("classpath:data-access-config.xml");   
                DynamicLoadBean dynamicBeanLoad =(DynamicLoadBean)ctx.getBean("dynamicLoadBean");

        dynamicBeanLoad.loadBean("data-access-dynamicConfig.xml");
        MagazineService magezineService = (MagazineService)ctx.getBean("magazineService");

[b]data-access-config.xml文件中包含原始的bean, data-access-dynamicConfig.xml文件中包含要动态加载的bean的配置文件。

不要忘了把DyanmicLoanBean 配置到原始的spring context 配置文件中也就时data-access-config.xml中[/b]

   <bean id="dynamicLoadBean" class="com.spring.dynamic.DynamicLoadBean">       
   </bean>

[b]动态加载的bean的配置文件[/b]

   <bean id="magazineService" class="com.ibank.test.openjpa.dao.MagazineServiceImpl">  
      <property name="magazineDao" ref="magazineDao"/>  
   </bean>

当然了动态加载的bean也可以reference 到原始的context中的bean.比如magazineDao就是在data-access-config.xml中配置的一个bean.