隐式的bean发现机制与自动装配后报空指针异常不知道错在哪求请教

Question

package com.immoc.beanAutoWiring;import org.junit.Test;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;import org.springframework.stereotype.Component;@Componentpublic class BeanAnnDemo { @Autowired private BeanAnnotation beanAnnotation; public static void main(String[] args) { //ApplicationContext applicationContext=new ClassPathXmlApplicationContext("applicationContent2.xml"); BeanAnnDemo demo=new BeanAnnDemo(); demo.test(); } public  void test(){ beanAnnotation.myHashcode(); beanAnnotation.say("this a test"); }}package com.immoc.beanAutoWiring;import org.springframework.context.annotation.Scope;import org.springframework.stereotype.Component;@Scope("prototype")@Componentpublic class BeanAnnotation { public void say(String string){ System.out.println("BeanAnnotation"+string); } public void myHashcode(){ System.out.println("BeanAnnotation"+this.hashCode()); }}<?xml version="1.0" encoding="UTF-8"?><!-- 指定Spring配置文件的DTD信息 --><beans xmlns="http://www.springframework.org/schema/beans"       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"       xmlns:context="http://www.springframework.org/schema/context"       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">    <context:component-scan base-package="com.immoc.beanAutoWiring"  /></beans>error:Exception in thread "main" java.lang.NullPointerException at com.immoc.beanAutoWiring.BeanAnnDemo.test(BeanAnnDemo.java:22) at com.immoc.beanAutoWiring.BeanAnnDemo.main(BeanAnnDemo.java:18)

Answer 1

你这种问题台笼统化，不贴代码错误信息啥的我们不可能帮的了你

Answer 2

                               <context:component-scan base-package="com.immoc"  />扫描所有同类型的包                             报错空指针是没找到

Answer 3

代码如上