项目中我遇到同样的问题 特记载一下

有两种方式

 

一、

该类使用@Component注解

添加一个本类类型的静态字段

创建一个初始化方法，贴上@PostConstruct 标签，用于注入bean

创建方法调用mapper或service接口

最后直接在普通类中调用即可

@Component泛指组件，当组件不好归类的时候，我们可以使用这个注解进行标注。

 被@PostConstruct修饰的方法会在服务器加载Servlet的时候运行，并且只会被服务器调用一次，类似于Serclet的inti()方法。被@PostConstruct修饰的方法会在构造函数之后，init()方法之前运行。

个人理解就是mapper 装载失败 重点init()方法中转了一次

@Componentpublic class TestUtil {    @Autowired    private DoctorInformationMapper doctorInformationMapper;    public static TestUtil testUtil;    @PostConstruct    public void init() {        testUtil = this;        testUtil.doctorInformationMapper = this.doctorInformationMapper;    }    //调用    public static int getOpenId() {        int count = testUtil.doctorInformationMapper.count("12313");        return count;    }    }

 

二。通过spring 容器去拿

2.1首先打印出Spring容器所有的Bean名称

@Componentpublic class ApplicationContextBean implements ApplicationContextAware, InitializingBean {    public static ApplicationContext applicationContext;    /**     * 获取 ApplicationContext     *     * @param applicationContext     * @throws BeansException     */    @Override    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {        ApplicationContextBean.applicationContext = applicationContext;    }    /**     * 打印IOC容器中所有的Bean名称     *     * @throws Exception     */    @Override    public void afterPropertiesSet() throws Exception {        String[] names = applicationContext.getBeanDefinitionNames();        for (String name : names) {            System.out.println(">>>>>>" + name);        }       System.out.println("------\nBean 总计:" + applicationContext.getBeanDefinitionCount());    }}

不用调用测试，项目启动就会在后台打印出来

 

2.2开始写获取bean工具类

@Componentpublic class SpringUtil implements ApplicationContextAware {    private static ApplicationContext applicationContext = null;    public SpringUtil() {    }    public void setApplicationContext(ApplicationContext arg0) throws BeansException {        if (applicationContext == null) {            applicationContext = arg0;        }    }    public static ApplicationContext getApplicationContext() {        return applicationContext;    }    public static void setAppCtx(ApplicationContext webAppCtx) {        if (webAppCtx != null) {            applicationContext = webAppCtx;        }    }    /**     * 拿到ApplicationContext对象实例后就可以手动获取Bean的注入实例对象     */    public static 
     
       T getBean(Class
      
        clazz) {        return getApplicationContext().getBean(clazz);    }    public static 
       
         T getBean(String name, Class
        
          clazz) throws ClassNotFoundException {        return getApplicationContext().getBean(name, clazz);    }    public static final Object getBean(String beanName) {        return getApplicationContext().getBean(beanName);    }    public static final Object getBean(String beanName, String className) throws ClassNotFoundException {        Class clz = Class.forName(className);        return getApplicationContext().getBean(beanName, clz.getClass());    }    public static boolean containsBean(String name) {        return getApplicationContext().containsBean(name);    }    public static boolean isSingleton(String name) throws NoSuchBeanDefinitionException {        return getApplicationContext().isSingleton(name);    }    public static Class
          getType(String name) throws NoSuchBeanDefinitionException {        return getApplicationContext().getType(name);    }    public static String[] getAliases(String name) throws NoSuchBeanDefinitionException {        return getApplicationContext().getAliases(name);    }　　//测试    public static String getCharId(String chatId) {        ChatListAssociationMapper associationMapper = (ChatListAssociationMapper) SpringUtil.getBean("chatListAssociationMapper");//这个参数是spring容器里存在的，名字最好复制，大小写要一致，不然会失败        return associationMapper.chatId(chatId);    }}
        
       
      
     

 

注意以上的两种方法都不能在main方法调用，会报空指针异常