SSH中遇到一个异常不知道是什么原因...

Question

Dao的代码如下:public class UserDaoImpl extends HibernateDaoSupport implements UserDao
{
public void save(Users user) 
{
getHibernateTemplate().save(user);
}}Service代码如下:public class UserServiceImpl implements UserService 
{
private UserDao userDao;
public UserDao getUserDao()
{
return userDao;
}
public void setUserDao(UserDao userDao)
{
this.userDao = userDao;
}

public void saveUser(String firstname,String lastname,String age) 
{ Users u = new Users();
u.setFirstname(firstname);
u.setLastname(lastname);
u.setAge(age);
System.out.println(firstname);
System.out.println(lastname);
System.out.println(age);System.out.println(u);
userDao.save(u);
}
}Action的代码如下:public class UserAction extends Action { private UserService userService;

public UserService getUserService() {
return userService;
} public void setUserService(UserService userService) {
this.userService = userService;
} public ActionForward execute(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response) 
{
DynaValidatorForm userForm = (DynaValidatorForm) form;
UserServiceImpl us = new UserServiceImpl();
String firstname = userForm.getString("firstname");
String lastname = userForm.getString("lastname");
String age = userForm.getString("age");
System.out.println("fff:"+firstname);
System.out.println("fff:"+lastname);
System.out.println("fff:"+age);
us.saveUser(firstname, lastname, age);

return mapping.findForward("success");
}
}错误报告如下:2009-6-8 9:25:03 org.apache.catalina.core.StandardWrapperValve invoke
严重: Servlet.service() for servlet action threw exception
java.lang.NullPointerException
at com.test.service.impl.UserServiceImpl.saveUser(UserServiceImpl.java:31)
at com.test.struts.action.UserAction.execute(UserAction.java:42)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:286)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:845)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Thread.java:619)

Answer 1

action 的 type 
因为ACTION要交给SPRING管理。

Answer 2

也可能是spring 与ACTION配错了。把ACTION和applicationContext.xml贴出来一下。

Answer 3

<?xml version="1.0" encoding="UTF-8"?>
<beans
xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd">
<bean id="dataSource"
class="org.apache.commons.dbcp.BasicDataSource">
<property name="driverClassName"
value="com.mysql.jdbc.Driver">
</property>
<property name="url"
value="jdbc:mysql://localhost:3306/mytest">
</property>
<property name="username" value="root"></property>
<property name="password" value="123456"></property>
</bean>
<bean id="sessionFactory"
class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
<property name="dataSource">
<ref bean="dataSource" />
</property>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">
org.hibernate.dialect.MySQLDialect
</prop>
</props>
</property>
<property name="mappingResources">
<list>
<value>com/test/model/Users.hbm.xml</value></list>
</property>
</bean>
<bean id="userDao" class="com.test.dao.impl.UserDaoImpl">
<property name="sessionFactory" ref="sessionFactory"></property>
</bean>

<bean id="userService" class="com.test.service.impl.UserServiceImpl">
<property name="userDao" ref="userDao"></property>
</bean>

<bean name="/user" class="com.test.struts.action.UserAction">
<property name="userService" ref="userService"></property>
</bean>

</beans>

Answer 4

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts-config PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 1.2//EN" "http://struts.apache.org/dtds/struts-config_1_2.dtd"><struts-config>
  <data-sources />
  <form-beans >
    <form-bean name="userForm" type="org.apache.struts.validator.DynaValidatorForm">
      <form-property name="lastname" type="java.lang.String" />
      <form-property name="age" type="java.lang.String" />
      <form-property name="firstname" type="java.lang.String" />
    </form-bean>  </form-beans>  <global-exceptions />
  <global-forwards />
  <action-mappings >
    <action
      attribute="userForm"
      input="/index.jsp"
      name="userForm"
      path="/user"
      scope="request"
      validate="false"
      >
      <forward name="success" path="/success.jsp" />
      <forward name="failure" path="/index.jsp" />
    </action>
  </action-mappings>  <controller
   processorClass="org.springframework.web.struts.DelegatingRequestProcessor">
  </controller>
  <message-resources parameter="com.test.struts.ApplicationResources" />
  <plug-in className="org.springframework.web.struts.ContextLoaderPlugIn">
    <set-property property="contextConfigLocation" value="/WEB-INF/applicationContext.xml" />
  </plug-in></struts-config>