@Autowired not working 的问题

Looks like the UserService class is missing a ‘stereotype’ annotation like @Component or @Service. You also have to configure the Spring classpath scanning using the following configuration:

<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-3.0.xsd
           http://www.springframework.org/schema/context
           http://www.springframework.org/schema/context/spring-context-3.0.xsd">

     <!-- Add your classes base package here -->          
     <context:component-scan base-package="your.package"/></beans>

Your beans must include one of the Spring stereotype annotations like:

package your.package;

@Service public class UserService { 
    // code goes here
}