從autowired bean獲取數據源時的空指針異常

我剛剛創建了一個spring mvc項目，除了web.xml,spring-servlet.xml和ListnerClass.java之外沒有任何內容。
我想在服務器啓動過程中初始化系統屬性。爲此，我創建了一個servlet上下文從autowired bean獲取數據源時的空指針異常

public class ListnerClass implements ServletContextListener{ 

    @Autowired 
    private DataSource dataSource; 

    @Override 
    public void contextDestroyed(ServletContextEvent arg0) { 

    } 

    @Override 
    public void contextInitialized(ServletContextEvent arg0) { 

     /* code for initializing system properties */ 
    Connection conn=dataSource.getConnection(); 

}

我得到NullPointerExceptin這行Connection conn=dataSource.getConnection();

的web.xml

<?xml version="1.0" encoding="UTF-8"?> 
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
    xmlns="http://java.sun.com/xml/ns/javaee" 
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" 
    id="WebApp_ID" version="3.0"> 

    <servlet> 
     <servlet-name>spring</servlet-name> 
     <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> 
     <load-on-startup>1</load-on-startup> 
    </servlet> 
    <servlet-mapping> 
     <servlet-name>spring</servlet-name> 
     <url-pattern>/</url-pattern> 
    </servlet-mapping> 
    <listener> 
     <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> 
    </listener> 

    <context-param> 
     <param-name>contextConfigLocation</param-name> 
     <param-value> 
      /WEB-INF/spring-servlet.xml 
     </param-value> 
    </context-param> 
    <listener> 
     <listener-class>com.infocentercache.manager.ListnerClass</listener-class> 
    </listener> 

</webapp>

爲spring-servlet.xml

<?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:mvc="http://www.springframework.org/schema/mvc" 
    xsi:schemaLocation="http://www.springframework.org/schema/mvc 
     http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd 
     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"> 

<context:annotation-config/> 

    <bean id="dataSource" class="org.apache.tomcat.jdbc.pool.DataSource"> 

     <property name="driverClassName" value="com.mysql.jdbc.Driver" /> 
     <property name="url" value="jdbc:mysql://localhost:3306/infocenter" /> 
     <property name="username" value="root" /> 
     <property name="password" value="gaurav" /> 
    </bean> 
</beans>

來源

2014-01-06 Gaurav Sharma

不知道，但即使之前運行春天來生活上下文監聽器將被初始化。因此自動佈線可能不起作用。數據源實例不會自動初始化。你應該直接使用JNDI API來查找上下文初始化方法 –