spring配置dwr时出错,急,在线等....

[I520WUCHAN]

请各位高手帮忙看以下异常是什么原因造成的
配置web.xml如下

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4"
xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<servlet>
<servlet-name>dwr</servlet-name>
<servlet-class>org.directwebremoting.spring.DwrSpringServlet</servlet-class>
<init-param>
<param-name>debug</param-name>
<param-value>true</param-value>
</init-param>
<load-on-startup>1</load-on-startup >

</servlet>
<servlet-mapping>
<servlet-name>dwr</servlet-name>
<url-pattern>/dwr/*</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
==================================
配置applicationContext.xml如下

<?xml version="1.0" encoding="UTF-8"?>
<beans
xmlns ="http://www.springframework.org/schema/beans"

xmlns:dwr ="http://www.directwebremoting.org/schema/spring-dwr"

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.xsd
http://www.directwebremoting.org/schema/spring-dwr http://www.directwebremoting.org/schema/spring-dwr-2.0.xsd" >
<!-- DWR 配置开始 -->
<dwr:configuration>
<dwr:convert class ="com.sp.action.User" type ="bean">
<dwr:exclude method ="getName" />
</dwr:convert >
</dwr:configuration><!-- 必须要configuration -->
<bean id="ddd" class="com.sp.action.User">
<dwr:remote javascript="User"></dwr:remote>
</bean>
</beans>

异常如下
============================
严重: StandardWrapper.Throwable
java.lang.NullPointerException
at org.directwebremoting.spring.DwrSpringServlet.init(DwrSpringServlet.java:136)
at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1161)
at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:981)
at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:4045)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4351)
at org.apache.catalina.startup.HostConfig.checkResources(HostConfig.java:1105)
at org.apache.catalina.startup.HostConfig.check(HostConfig.java:1203)
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:293)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
at org.apache.catalina.core.ContainerBase.backgroundProcess(ContainerBase.java:1337)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1601)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1610)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1590)
at java.lang.Thread.run(Unknown Source)
2008-12-3 17:37:04 org.apache.catalina.core.StandardContext loadOnStartup
严重: Servlet /SpringAndDwr threw load() exception
java.lang.NullPointerException
at org.directwebremoting.spring.DwrSpringServlet.init(DwrSpringServlet.java:136)
at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1161)
at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:981)
at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:4045)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4351)
at org.apache.catalina.startup.HostConfig.checkResources(HostConfig.java:1105)
at org.apache.catalina.startup.HostConfig.check(HostConfig.java:1203)
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:293)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
at org.apache.catalina.core.ContainerBase.backgroundProcess(ContainerBase.java:1337)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1601)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1610)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1590)
at java.lang.Thread.run(Unknown Source)

===================================================
以上异常为什么会报空值呢?我找了好久也没有找出决解的方法,所以请大家忙小弟决解一下,谢了....

[I520WUCHAN]

补充
页面代码如下
<%@ page language="java" pageEncoding="utf-8"%>
<html>
<head>
<title>My JSP 'index.jsp' starting page</title>
<script type="text/javascript" src="dwr/interface/User.js"></script>
<script type="text/javascript" src="dwr/engine.js"></script>
<script type="text/javascript" src="dwr/util.js"></script>
<script type="text/javascript">
function users()
{
alert('dddd');
var name=${"username"}.value;
alert(name);
User.getName(name,us);
}

function us(isboolean)
{
if(isboolean==true)
{
alert('isexists');
}else
{
alert('not exists');
}
}
</script>
</head>

<body>
<input type="text" name="username">
<input type="button" value="ok" onclick="users()">
</body>
</html>

[睿音]

从所列出来的代码暂时还是没有找到问题。web.xml配置没有问题。最好的方式还是通过调试看下空指针是在哪里出现的。

Ps.dwr调用Spring类时可以这样来配置：

<create javascript="jsname" creator="spring">
<param name="beanName" value="beanId" />
</create> 

[tzb08]

debug进去 看哪里报null了？？

[zou_wei_forever]

友情up，关注。。。

[牛十二]

<bean id="ddd" class="com.sp.action.User">
<dwr:remote javascript="User"> </dwr:remote>
</bean>
应该写成
<bean id="ddd" class="com.sp.action.User">
<dwr:remote javascript="Users"> </dwr:remote>
</bean>

[西瓜]

关注
没遇到过