No mapping found for HTTP request with URI [/exam3/welcome] in DispatcherServlet

项目是使用spring MVC
（1）在浏览器中访问，后台总报错：
No mapping found for HTTP request with URI [/exam3/welcome] in DispatcherServlet with name 'spring2' 
查了好半天，才发现是controller 没有扫描到。
我是使用的注解。
spring mvc配置文件如下：
Xml代码  收藏代码
<?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:context="http://www.springframework.org/schema/context" 
    xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx" 
    xmlns:mvc="http://www.springframework.org/schema/mvc" 
    xsi:schemaLocation="http://www.springframework.org/schema/beans 
           http://www.springframework.org/schema/beans/spring-beans-3.2.xsd 
            http://www.springframework.org/schema/context 
           http://www.springframework.org/schema/context/spring-context-3.2.xsd 
           http://www.springframework.org/schema/aop 
           http://www.springframework.org/schema/aop/spring-aop-3.2.xsd 
           http://www.springframework.org/schema/tx  
           http://www.springframework.org/schema/tx/spring-tx-3.2.xsd 
           http://www.springframework.org/schema/mvc  
           http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd" 
           > 
 
    <!-- HandlerMapping --> 
    <bean 
        class="org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping" /> 
 
    <!-- HandlerAdapter --> 
    <bean 
        class="org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter" /> 
    <!-- ViewResolver --> 
    <bean 
        class="org.springframework.web.servlet.view.InternalResourceViewResolver"> 
        <property name="viewClass" 
            value="org.springframework.web.servlet.view.JstlView" /> 
        <property name="prefix" value="/WEB-INF/jsp/" /> 
        <property name="suffix" value=".jsp" /> 
    </bean> 
<mvc:annotation-driven /> 
<!-- 处理器 -->   
<!-- <bean name="/hello" class="com.mvc.jn.controller.HelloWorldController"/> --> 
<context:component-scan base-package="com"/> 
</beans> 
controller 的目录结构如下：




（2）这个问题解决之后，又报错：
No mapping found for HTTP request with URI [/exam3/WEB-INF/jsp/welcome.jsp] in DispatcherServlet with name 'spring2'
结果发现是web.xml配置得有问题，下面是有问题的：
Xml代码  收藏代码
<servlet> 
        <servlet-name>spring2</servlet-name> 
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> 
        <load-on-startup>1</load-on-startup> 
    </servlet> 
    <servlet-mapping> 
        <servlet-name>spring2</servlet-name> 
        <url-pattern>/*</url-pattern> 
    </servlet-mapping> 
解决方法：把url-pattern 由/* 改为/