最近用springboot做了一个服装推荐网，发现了一个奇葩问题，在这里记录一下。

问题现象如下：

如果StartupRunner implements CommandLineRunner,ServletContextListener，那么windows下开发环境正常，application是有值的，不为空；

但是一旦将该工程达成war包，找个tomcat服务器运行，那么application就是null了，

后面通过查阅资料，得到结论，只要implements CommandLineRunner，那么这个类（StartupRunner）就会伴随tomcat启动而加载运行，相当于

一个监听器，同时还能当做spring所管理的组件来用，可以将application直接注入到当前类来；

最终代码如下

package com.javaxl.clothes.component;

import javax.servlet.ServletContext;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.annotation.WebListener;

import com.javaxl.clothes.entity.Clothes;
import com.javaxl.clothes.entity.ClothesType;
import com.javaxl.clothes.service.ClothesService;
import com.javaxl.clothes.service.ClothesTypeService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.stereotype.Component;
import org.springframework.web.context.support.WebApplicationContextUtils;

import java.util.List;

@Component("startupRunner")
public class StartupRunner implements CommandLineRunner{

	@Autowired
	private ServletContext application;

	@Autowired
	private ClothesService clothesService;
	@Autowired
	private ClothesTypeService clothesTypeService;
	

	@Override
	public void run(String... args) throws Exception {
		this.loadData();
	}
	
	/**
	 * 加载数据到applicaton缓存中
	 */
	public void loadData(){
		Clothes clothes = new Clothes();
		clothes.setHot(1);
//		水平导航栏展示（6个分类）
		List<ClothesType> clothesTypeMenus = clothesTypeService.list(null, 0, 6);
//		首页最新最热的32种服装
		List<Clothes> newestIndexHotClothesList = this.clothesService.list(clothes, 0, 32);
//		右侧最新的10种服装
		List<Clothes> newestClothesList = this.clothesService.list(null, 0, 16);
//		右侧最新最热的10中服装
		List<Clothes> newestHotClothesList = this.clothesService.list(clothes, 0, 16);

		application.setAttribute("clothesTypeMenus",clothesTypeMenus);
		application.setAttribute("newestIndexHotClothesList",newestIndexHotClothesList);
		application.setAttribute("newestClothesList",newestClothesList);
		application.setAttribute("newestHotClothesList",newestHotClothesList);
	}

//	@Override
//	public void contextInitialized(ServletContextEvent sce) {
//		application=sce.getServletContext();
//		WebApplicationContextUtils.getRequiredWebApplicationContext(sce.getServletContext())
//				.getAutowireCapableBeanFactory().autowireBean(this);
//	}
//
//	@Override
//	public void contextDestroyed(ServletContextEvent sce) {
//
//	}

}

over....