/**
 * 服務工廠介面.
 * 
 * 
 *
 */
public interface ServiceFactory extends Serializable {

    /**
     * 獲取服務，通過class.
     * 
     * @param clazz
     * @return
     */
    public <T> T getService(Class<T> clazz);

    /**
     * 獲取服務，通過beanId.
     * 
     * @param beanId
     * @param clazz
     * @return
     */
    public <T> T getService(String beanId, Class<T> clazz);
}
 

import java.io.Serializable;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.stereotype.Component;
import org.springframework.util.StringUtils;

/**
 * 
 * 本地服務工廠.
 * 
 *
 */
@Component
public class LocalServiceFactory implements Serializable, ServiceFactory, BeanFactoryAware {

    private static final long serialVersionUID = -4829342420862083368L;
    private BeanFactory beanFactory;

    @Override
    public <T> T getService(Class<T> clazz) {

        String beanId = this.getServiceName(clazz, null);
        return beanFactory.getBean(beanId, clazz);
    }

    @Override
    public <T> T getService(String beanId, Class<T> clazz) {
        beanId = this.getServiceName(clazz, beanId);
        return beanFactory.getBean(beanId, clazz);
    }

    private <T> String getServiceName(final Class<T> clazz, final String serviceName) {
        String beanName = serviceName;
        if (!StringUtils.hasLength(serviceName)) {
            // 得到HelloService
            beanName = clazz.getName().substring(clazz.getName().lastIndexOf(".") + 1);
            // 首字母小寫,得到helloService
            beanName = beanName.substring(0, 1).toLowerCase() + beanName.substring(1);
        }
        return beanName;
    }

    @Override
    public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
        this.beanFactory = beanFactory;
    }

}
 

/**
 * 以靜態變數儲存Spring ApplicationContext, 可在任何程式碼任何地方任何時候中取出ApplicaitonContext.
 * 
 * 
 */
public class SpringContextHolder implements ApplicationContextAware {

	private static ApplicationContext applicationContext;

	/**
	 * 實現ApplicationContextAware介面的context注入函式, 將其存入靜態變數.
	 */
	public void setApplicationContext(ApplicationContext applicationContext) {
		SpringContextHolder.applicationContext = applicationContext;
	}

	/**
	 * 取得儲存在靜態變數中的ApplicationContext.
	 */
	public static ApplicationContext getApplicationContext() {
		checkApplicationContext();
		return applicationContext;
	}

	/**
	 * 從靜態變數ApplicationContext中取得Bean, 自動轉型為所賦值物件的型別.
	 */
	@SuppressWarnings("unchecked")
	public static <T> T getBean(String name) {
		checkApplicationContext();
		return (T) applicationContext.getBean(name);
	}

	/**
	 * 從靜態變數ApplicationContext中取得Bean, 自動轉型為所賦值物件的型別. 如果有多個Bean符合Class, 取出第一個.
	 */
	@SuppressWarnings("unchecked")
	public static <T> T getBean(Class<T> clazz) {
		checkApplicationContext();
		Map beanMaps = applicationContext.getBeansOfType(clazz);
		if (beanMaps != null && !beanMaps.isEmpty()) {
			return (T) beanMaps.values().iterator().next();
		} else {
			return null;
		}
	}

	private static void checkApplicationContext() {
		if (applicationContext == null) {
			throw new IllegalStateException("applicaitonContext未注入,請在applicationContext.xml中定義SpringContextHolder");
		}
	}
}