JAVA解决在@autowired,@Resource注入为null的问题

来源：互联网发布：大连网络建站编辑：程序博客网时间：2024/05/22 02:02

使用SpringMVC或者SSH过程中，有时可能会遇到这么一个问题。就是在一个普通的JAVA类（不是controller也不是action类）中无法注入在spring配置文件中配置的bean。比如你在一个普通java类想调用某个在spring中配置的service，你会发现不管你用@Resource还是@Autowired注解都无法注入，对象始终是null。那是因为一般普通的Java类没有被spring代理，自然无法通过spring注入相关的对象。难道这样就不能调用了吗？这里提供下面一个类来解决这个问题：

SpringContextUtil

package com.im.utils;import org.springframework.beans.BeansException;import org.springframework.beans.factory.NoSuchBeanDefinitionException;import org.springframework.context.ApplicationContext;import org.springframework.context.ApplicationContextAware;/** * 这个类是为了解决在普通类调用service的问题 *  * @ClassName SpringContextUtil * @Description * @author kokjuis 189155278@qq.com * @date 2016-6-12 * @content *       */public class SpringContextUtil implements ApplicationContextAware {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@Overridepublic 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);}}

然后在spring配置文件中配置一下这个类：

<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:tx="http://www.springframework.org/schema/tx"xmlns:aop="http://www.springframework.org/schema/aop" xmlns:task="http://www.springframework.org/schema/task"xmlns:cache="http://www.springframework.org/schema/cache"xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.3.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.3.xsd       http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.3.xsd      http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task-4.3.xsd      http://www.springframework.org/schema/cache http://www.springframework.org/schema/cache/spring-cache.xsd"><!--配置spring工具类 --><bean id="SpringContextUtil" class="com.im.utils.SpringContextUtil"scope="singleton"></bean></beans>

然后通过这个类提供的方法就能正常的获取在spring中托管的bean了，使用很简单：

/**     * 获取spring托管的redis连接池     */    private JedisPool jedisPool = (JedisPool) SpringContextUtil.getBean("jedisPool");

阅读全文

0 0