使用spring时，无法注入（提示：java.lang.NullPointerException）

Question

异常信息如下：
org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.NullPointerException
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:408)
org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:360)
javax.servlet.http.HttpServlet.service(HttpServlet.java:710)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:78)
org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:77)
root cause
java.lang.NullPointerException
com.test.dao.jdbc.UserDAO.insert(UserDAO.java:11)
com.test.controller.LoginController.onSubmit(LoginController.java:21)
org.springframework.web.servlet.mvc.SimpleFormController.onSubmit(SimpleFormController.java:408)
org.springframework.web.servlet.mvc.SimpleFormController.onSubmit(SimpleFormController.java:380)
org.springframework.web.servlet.mvc.SimpleFormController.processFormSubmission(SimpleFormController.java:267)
org.springframework.web.servlet.mvc.AbstractFormController.handleRequestInternal(AbstractFormController.java:250)
org.springframework.web.servlet.mvc.AbstractController.handleRequest(AbstractController.java:153)
org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter.handle(SimpleControllerHandlerAdapter.java:45)
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:820)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:755)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:396)
org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:360)
javax.servlet.http.HttpServlet.service(HttpServlet.java:710)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:78)
org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:77)

web.xml

<display-name>TestDemo</display-name>

<context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>/WEB-INF/applicationContext.xml</param-value>
</context-param>

<servlet>
    <servlet-name>context</servlet-name>
    <servlet-class>org.springframework.web.context.ContextLoaderServlet</servlet-class>
    <load-on-startup>1</load-on-startup>
</servlet>

<filter>
    <filter-name>encodingFilter</filter-name>
    <filter-class>
        org.springframework.web.filter.CharacterEncodingFilter
    </filter-class>
    <init-param>
        <param-name>encoding</param-name>
        <param-value>UTF-8</param-value>
    </init-param>
</filter>

<filter-mapping>
    <filter-name>encodingFilter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

<servlet>
    <servlet-name>dispatcherServlet</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <load-on-startup>1</load-on-startup>
</servlet>

<servlet-mapping>
    <servlet-name>dispatcherServlet</servlet-name>
    <url-pattern>*.do</url-pattern>
</servlet-mapping>

applicationContext.xml:

<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="com.microsoft.jdbc.sqlserver.SQLServerDriver">
<property name="url" value="jdbc:sqlserver://localhost:1433;databaseName=test">
<property name="username" value="sa">
<property name="password" value="">
</bean>

<bean id="sessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
    <property name="dataSource" ref="dataSource"></property>
    <property name="mappingResources">
        <list>
            <value>com/test/domain/User.hbm.xml</value>
        </list>
    </property>
    <property name="hibernateProperties">
        <props>
            <prop key="hibernate.dialect">org.hibernate.dialect.SQLServerDialect</prop>
        </props>
    </property>
</bean>

<bean id="userDAO" class="com.test.dao.jdbc.UserDAO">
    <property name="sessionFactory" ref="sessionFactory">
</bean>

dispatcherServlet-servlet.xml:
<bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/"></property>
<property name="suffix" value=".jsp"></property>
</bean>

<bean id="urlMapping" class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping">
    <property name="mappings">
        <props>
            <prop key="/login.do">loginController</prop>
        </props>
    </property>
</bean>

<bean id="loginController" class="com.test.controller.LoginController">
    <property name="successView" value="/admin/success"></property>
    <property name="formView" value="/admin/login"></property>
</bean>

UserDAO.java:

public class UserDAO extends BaseDao implements IUserDAO {

public void insert(User user) {
    System.out.println("hibernateTemplate: " + this.getHibernateTemplate());
    this.getHibernateTemplate().update("INSERT INTO USERPASS (USERNAME, PASSWORDS) VALUES ('" + user.getUserName() +"', '" + user.getPassword() + "')");
}

public User find(Integer id) {
    List rows = this.getHibernateTemplate().find("SELECT * FROM USERPASS WHERE ID=" + id.intValue());
    Iterator it = rows.iterator();
    if(it.hasNext()) {
        Map userMap = (Map)it.next();
        User user = new User();
        user.setUserName(userMap.get("USERNAME").toString());
        user.setPassword(userMap.get("PASSWORDS").toString());
        return user;
    }
    return null;
}

}

Answer 1

至少把你的配置文件等相关信息也贴出来吧。详见：[url=http://www.iteye.com/topic/29434]JavaEye论坛提问的智慧 [/url]