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)