SpringContextHolder工具类，在Spring应用中创建全局获取ApplicationContext对象

package cn.maitian.bss.duty.privilege.utils;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.util.Assert;

/**
 * 以静态变量保存Spring ApplicationContext, 可在任何代码任何地方任何时候取出ApplicaitonContext.
 * User: liguo
 * Date: 13-9-26
 * Time: 下午3:40
 * To change this template use File | Settings | File Templates.
 */
public class SpringContextHolder implements ApplicationContextAware, DisposableBean {

    private static ApplicationContext applicationContext = null;

    private static Logger logger = LoggerFactory.getLogger(SpringContextHolder.class);

    /**
     * 取得存储在静态变量中的ApplicationContext.
     */
    public static ApplicationContext getApplicationContext() {
        assertContextInjected();
        return applicationContext;
    }

    /**
     * 从静态变量applicationContext中取得Bean, 自动转型为所赋值对象的类型.
     */
    @SuppressWarnings("unchecked")
    public static <T> T getBean(String name) {
        assertContextInjected();
        return (T) applicationContext.getBean(name);
    }

    /**
     * 从静态变量applicationContext中取得Bean, 自动转型为所赋值对象的类型.
     */
    @SuppressWarnings("unchecked")
    public static <T> T getBean(Class<T> requiredType) {
        assertContextInjected();
        String[] beanNames = applicationContext.getBeanNamesForType(requiredType);
        if(beanNames!=null && beanNames.length>0){
            return (T)applicationContext.getBean(beanNames[0]);
        }

        return null;
    }



    /**
     * 清除SpringContextHolder中的ApplicationContext为Null.
     */
    public static void clearHolder() {
        logger.debug("清除SpringContextHolder中的ApplicationContext:"+ applicationContext);
        applicationContext = null;
    }

    /**
     * 实现ApplicationContextAware接口, 注入Context到静态变量中.
     */
    @Override
    public void setApplicationContext(ApplicationContext applicationContext) {
//        logger.debug("注入ApplicationContext到SpringContextHolder:{}", applicationContext);

        if (SpringContextHolder.applicationContext != null) {
            logger.warn("SpringContextHolder中的ApplicationContext被覆盖, 原有ApplicationContext为:" + SpringContextHolder.applicationContext);
        }

        SpringContextHolder.applicationContext = applicationContext; // NOSONAR
    }

    /**
     * 实现DisposableBean接口, 在Context关闭时清理静态变量.
     */
    @Override
    public void destroy() throws Exception {
        SpringContextHolder.clearHolder();
    }

    /**
     * 检查ApplicationContext不为空.
     */
    private static void assertContextInjected() {
        //Validate.validState(applicationContext != null, "applicaitonContext属性未注入, 请在applicationContext.xml中定义SpringContextHolder.");
        Assert.state(applicationContext != null, "applicaitonContext属性未注入, 请在applicationContext.xml中定义SpringContextHolder.");
    }
}