特别提醒：一定要注意文件结构
WebappApplication 一定要在包的最外层，否则Spring无法对所有的类进行托管，会造成@Autowired 无法注入。
1. 添加工具类获取在 Spring 中托管的 Bean
（1）工具类
package com.common;import org.springframework.beans.BeansException;import org.springframework.beans.factory.NoSuchBeanDefinitionException;import org.springframework.context.ApplicationContext;import org.springframework.context.ApplicationContextAware;/**
* @program: IPC_1P
* @description: 获取在spring中托管的bean
* @author: johnny
* @create: 2018-08-03 16:24
**/public class SpringContextUtil {private static ApplicationContext applicationContext; // Spring应用上下文// 下面的这个方法上加了@Override注解，原因是继承ApplicationContextAware接口是必须实现的方法public static void setApplicationContext(ApplicationContext applicationContext)throws BeansException {
SpringContextUtil.applicationContext = applicationContext;
}public static ApplicationContext getApplicationContext() {return applicationContext;
}public static Object getBean(String name) throws BeansException {return applicationContext.getBean(name);
}public static Object getBean(String name, Class requiredType)throws BeansException {return applicationContext.getBean(name, requiredType);
}public static boolean containsBean(String name) {return applicationContext.containsBean(name);
}public static boolean isSingleton(String name)throws NoSuchBeanDefinitionException {return applicationContext.isSingleton(name);
}public static Class getType(String name)throws NoSuchBeanDefinitionException {return applicationContext.getType(name);
}public static String[] getAliases(String name)throws NoSuchBeanDefinitionException {return applicationContext.getAliases(name);
}
}（2）使用
1）程序启动时，实例化 SpringContextUtil
@SpringBootApplicationpublic class WebappApplication {private static ApplicationContext applicationContext;public static void main(String[] args) {
applicationContext = SpringApplication.run(WebappApplication.class, args);// SpringContextUtil springContextUtil = new SpringContextUtil();
springContextUtil.setApplicationContext(applicationContext);
System.out.println("服务器启动测试!");
}
2）在使用 @Service 的方法中，通过@Autowired 注入，使用SpringcontexUtil 获取Bean上下文
@Autowired
SenderService senderService;public class Package_State {
@Autowired
SenderService senderService;
@Componentprivate Package_State() {
senderService = (SenderService)SpringContextUtil.getBean("senderService");
}
}
Java 初学，原理理解不很透彻，只针对遇到的问题进行记录，随着学习的深入随时修改
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