sping无法注入值，但是直接从配置文件读取又可以

Question

这是dao代码IBookDAOImpl代码package com.niit.dao.impl;import java.util.List;import org.hibernate.Query;
import org.springframework.orm.hibernate3.support.HibernateDaoSupport;import com.niit.dao.IBookDAO;
import com.niit.vo.Book;
import com.niit.vo.Bookcat;public class IBookDAOImpl extends HibernateDaoSupport implements IBookDAO {
public IBookDAOImpl() {
System.out.println("构造方法 IBookDAOImpl");
} public boolean delete(int id) {
// TODO Auto-generated method stub
return false;
} public boolean insert(Book b) {
// TODO Auto-generated method stub
return false;
} public List<Book> queryAll() {
System.out.println("111111111");
String hql = "FROM Book AS b";
List list = (List<Book>)super.getSession().createQuery(hql).list();
System.out.println("2222222222");
System.out.println(list.size());
return list;
} public Book selectById(int id) {
// TODO Auto-generated method stub
return null;
} public boolean update(Book b) {
// TODO Auto-generated method stub
return false;
}
public List<Book> queryByBookcat(Bookcat bookcat) {
System.out.println("11111111");
String hql = "FROM Book AS b where b.catid = ?";
Query q = super.getSession().createQuery(hql);
q.setInteger(0, bookcat.getCatid());
List<Book> list = q.list();
System.out.println("2222222");
return list;
}
}
IBookcatDaoImpl代码package com.niit.dao.impl;import java.util.List;import org.springframework.orm.hibernate3.support.HibernateDaoSupport;import com.niit.dao.IBookcatDao;
import com.niit.vo.Book;
import com.niit.vo.Bookcat;public class IBookcatDaoImpl extends HibernateDaoSupport implements IBookcatDao {
public IBookcatDaoImpl() {
System.out.println("构造方法      IBookcatDaoImpl");
} public void delete(int id) throws Exception {
// TODO Auto-generated method stub } public void insert(Bookcat bc) throws Exception {
// TODO Auto-generated method stub } public List<Bookcat> queryAll() throws Exception {
String hql = "FROM Bookcat AS bc";
List<Bookcat> list = (List<Bookcat>)super.getSession().createQuery(hql).list();
System.out.println(list.size());
return list;
} public Bookcat queryById(int itemid) throws Exception {
// TODO Auto-generated method stub
return null;
} public void update(Bookcat bc) throws Exception {
// TODO Auto-generated method stub }}

Answer 1

这是applicationContext.xml文件中的配置项<bean id="ibookdao" class="com.niit.dao.IBookDAO" abstract="true"></bean>
<bean id="ibookdaoimpl" class="com.niit.dao.impl.IBookDAOImpl" parent="ibookdao">
<property name="hibernateTemplate">
<ref bean="hibernateTemplate"/> 
</property>
</bean>

<bean id="ibookcatdao" class="com.niit.dao.IBookcatDao" abstract="true"></bean>
<bean id="ibookcatdaoimpl" class="com.niit.dao.impl.IBookcatDaoImpl" parent="ibookcatdao">
<property name="hibernateTemplate">
<ref bean="hibernateTemplate"/> 
</property>

</bean>
<bean name="/jsp/index" class="com.niit.struts.action.IndexAction">
<property name="ibookdao">
<ref local="ibookdaoimpl"/>
</property>
<property name="ibookcatdao">
<ref local="ibookcatdaoimpl"/>
</property>
</bean>
这是struts-config.xml中的相关配置  <form-beans >
<form-bean name="userForm" type="com.niit.struts.form.UserForm" />
<form-bean name="indexForm" type="org.apache.struts.action.DynaActionForm" />  </form-beans> <action attribute="indexForm" input="/jsp/errors.jsp"
name="indexForm" parameter="status" path="/jsp/index" scope="request"
type="com.niit.struts.action.IndexAction">
<forward name="indexdo" path="/jsp/index.jsp"></forward>
</action>

Answer 2

这是IndexAction.java代码 功能是为了点击一个衔接进入主页，而主页的内容需要从数据库中取出，然后显示出来/*
 * Generated by MyEclipse Struts
 * Template path: templates/java/JavaClass.vtl
 */
package com.niit.struts.action;import java.util.List;import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.action.DynaActionForm;
import org.apache.struts.actions.DispatchAction;
import org.springframework.context.support.ClassPathXmlApplicationContext;import com.niit.dao.IBookDAO;
import com.niit.dao.IBookcatDao;
import com.niit.dao.impl.IBookDAOImpl;
import com.niit.dao.impl.IBookcatDaoImpl;
import com.niit.vo.Book;
import com.niit.vo.Bookcat;/**
 * MyEclipse Struts Creation date: 07-02-2007
 * 
 * XDoclet definition:
 * 
 * @struts.action path="/index" name="indexForm" input="/form/index.jsp"
 *                parameter="status" scope="request" validate="true"
 */
public class IndexAction extends DispatchAction {
private IBookDAO ibookdao;
private IBookcatDao ibookcatdao ; /*
 * Generated Methods
 */
public IBookDAO getIbookdao() {
return ibookdao;
}
public IBookcatDao getIbookcatdao() {
return ibookcatdao;
}
public void setIbookcatdao(IBookcatDao ibookcatdao) {
System.out.println("=====set  ibookcatdao ========");
this.ibookcatdao = ibookcatdao;
}
public void setIbookdao(IBookDAO ibookdao) {
System.out.println("======set  ibookdao ===");
this.ibookdao = ibookdao;
}
/**
 * Method execute
 * 
 * @param mapping
 * @param form
 * @param request
 * @param response
 * @return ActionForward
 */
public ActionForward list(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response) {
DynaActionForm indexForm = (DynaActionForm) form;
// 查询信息
// ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext(
// "applicationContext.xml");
// ibookdao = (IBookDAOImpl)ctx.getBean("ibookdaoimpl");
// ibookcatdao = (IBookcatDaoImpl)ctx.getBean("ibookcatdaoimpl");
List<Book> list = null;
List<Bookcat> all = null;
try {
list  =  this.ibookdao.queryAll();
all =  this.ibookcatdao.queryAll();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
request.setAttribute("list", list);
request.setAttribute("all", all);
return mapping.findForward("indexdo");
}}
现在的问题是用sping注入不了值，taomcat启动的时候显示两个dao的构造方法和set方法都调用了，但是报空指针错误
构造方法 IBookDAOImpl
构造方法      IBookcatDaoImpl
======set  ibookdao ===
=====set  ibookcatdao ========
java.lang.NullPointerException
at com.niit.struts.action.IndexAction.list(IndexAction.java:86)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.struts.actions.DispatchAction.dispatchMethod(DispatchAction.java:270)
at org.apache.struts.actions.DispatchAction.execute(DispatchAction.java:187)
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 com.niit.filter.EncodingFilter.doFilter(EncodingFilter.java:21)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
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:127)
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:298)
at org.apache.coyote.http11.Http11AprProcessor.process(Http11AprProcessor.java:859)
at org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:579)
at org.apache.tomcat.util.net.AprEndpoint$Worker.run(AprEndpoint.java:1555)
at java.lang.Thread.run(Thread.java:619)
  但是如果我在indexaction中不使用set get方法，使用注释的那段代码，即如下代码，直接从配置文件读取，却正常使用，能取出值。 ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext(
"applicationContext.xml");
ibookdao = (IBookDAOImpl)ctx.getBean("ibookdaoimpl");
ibookcatdao = (IBookcatDaoImpl)ctx.getBean("ibookcatdaoimpl");
不知道是怎么回事？不知道有没有人知道原因

Answer 3

this.getSession().createQuery(hql).list();

Answer 4

去掉<bean id="ibookcatdao" class="com.niit.dao.IBookcatDao" abstract="true"></bean>
     删除红色   <bean id="ibookcatdaoimpl" class="com.niit.dao.impl.IBookcatDaoImpl" parent="ibookcatdao">
            <property name="hibernateTemplate">
            <ref bean="hibernateTemplate"/> 
        </property>
        </bean>

Answer 5

楼主，很明显spring的注入已经调用了，通过打印就能看出来，但是当你调用的时候又为null了，这说明你在点击页面的时候生成的action已经不是spring生成的action了，而是struts框架自己生成的action，所以我怀疑你是不是没有指定action的生成方式为spring注入。建议你检查一下你的配置文件。关于struts1如何与spring整合，网上有很多例子。

Answer 6

at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
这里有问题吧，是不是你struts的配置文件有问题呀。加<controller/>了么？
<controller processorClass="org.springframework.web.struts.DelegatingRequestProcessor"/>

Answer 7

如果要是没加<controller/>没配置的话，不知道 <plug-in className="org.springframework.web.struts.ContextLoaderPlugIn">
  <set-property property="contextConfigLocation" value="/WEB-INF/applicationContext.xml"/>
 </plug-in> 这个配置了没有。
还有就是如5喽所说，不清楚lz那么配置有什么特殊用意？？

Answer 8

<controller processorClass="org.springframework.web.struts.DelegatingRequestProcessor"></controller>
  <message-resources parameter="com.niit.struts.ApplicationResources" />
  <plug-in className="org.springframework.web.struts.ContextLoaderPlugIn">
   <set-property property="contextConfigLocation" value="/WEB-INF/applicationContext.xml"/>
  </plug-in>这些都配了 

Answer 9

学习spring时候看到的，尝试用一下，
  不过按照五楼的改回去了，还是一样的错误 郁闷

Answer 10

应该是struts的控制权没有交给spring，缺少相应的<controller>和<plugin>，还不行的话看看你spring的web包导了没？

Answer 11

还有个地，web.xml里配置了不。你看异常根本就没报spring相关的异常信息。

Answer 12

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" 
xmlns="http://java.sun.com/xml/ns/javaee" 
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<filter>
  <filter-name>encoding</filter-name>
  <filter-class>com.niit.filter.EncodingFilter</filter-class>
  <init-param>
<param-name>charset</param-name>
<param-value>gbk</param-value>
</init-param>
  </filter>
  <filter-mapping> 
    <filter-name>encoding</filter-name> 
    <url-pattern>/*</url-pattern> 
  </filter-mapping>
  
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>
/WEB-INF/classes/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>  
<servlet>
    <servlet-name>action</servlet-name>
    <servlet-class>org.apache.struts.action.ActionServlet</servlet-class>
    <init-param>
      <param-name>config</param-name>
      <param-value>/WEB-INF/struts-config.xml</param-value>
    </init-param>
    <init-param>
      <param-name>debug</param-name>
      <param-value>3</param-value>
    </init-param>
    <init-param>
      <param-name>detail</param-name>
      <param-value>3</param-value>
    </init-param>
    <load-on-startup>0</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>action</servlet-name>
    <url-pattern>*.do</url-pattern>
  </servlet-mapping>
</web-app>
web的配置了

Answer 13

        <bean name="/jsp/index" class="com.niit.struts.action.IndexAction">
            <property name="ibookdao">
                <ref local="ibookdaoimpl"/>
            </property>
            <property name="ibookcatdao">
                <ref local="ibookcatdaoimpl"/>
            </property>
        </bean>应该是这个action bean里面那2个没注入成功，试过用<context:annotation-config /> 用annotation注入吗

Answer 14

这个不会
我奇怪的是  构造方法和set方法都已经调用了。为什么注入不成功呢，我在调用那个查询前加了打印语句，显示两个都是null值

Answer 15

action中写上 IBookDAO ibookdao和IBookcatDao ibookcatdao的getter!!!!

Answer 16

    public IBookDAO getIbookdao() {
        return ibookdao;
    }
    public IBookcatDao getIbookcatdao() {
        return ibookcatdao;
    }
action中写上了

Answer 17

把servlet换成listener试试。
<listener>
<listener-class>
org.springframework.web.context.ContextLoaderListener
</listener-class>
</listener>