ActionForm中有个List变量，但是从页面中取回Lis值发生异常！

Question

在我程序中需要存一个List的值，实现方式类似这个例子：http://walnut.javaeye.com/blog/169559。
我是完全照着他的方法实现的，但是再我的程序中出现如下异常，大家帮忙来看看。
09:26:41,406 [http-8086-1] DEBUG BeanUtilsBean : 
BeanUtils.populate(com.rdc.struts.form.Manhours_searchresultForm@1148cfe, 
{voList[1].khgs=[Ljava.lang.String;@b41068, 
voList[0].fdjx=[Ljava.lang.String;@1a13d07, 
voList[1].tygs=[Ljava.lang.String;@adcecb, 
voList[1].khrxm=[Ljava.lang.String;@e3ad45, 
voList[1].fdjx=[Ljava.lang.String;@184ad44, 
voList[2].tygs=[Ljava.lang.String;@18b7738, 
voList[0].khgs=[Ljava.lang.String;@1403bdf, 
voList[2].sjgs=[Ljava.lang.String;@1ac7c2, 
voList[1].jhgs=[Ljava.lang.String;@30b168, 
voList[0].tygs=[Ljava.lang.String;@cf4bf9, 
voList[2].khrxm=[Ljava.lang.String;@184df6a, 
voList[2].jhgs=[Ljava.lang.String;@67d81d, 
voList[2].khgs=[Ljava.lang.String;@19d77ed, 
voList[2].fdjx=[Ljava.lang.String;@12c72aa, 
voList[0].khrxm=[Ljava.lang.String;@11c1b67, 
voList[0].sjgs=[Ljava.lang.String;@4b2375, 
voList[0].jhgs=[Ljava.lang.String;@104e1c2, 
voList[1].sjgs=[Ljava.lang.String;@1819776}) 09:26:41,421 [http-8086-1] DEBUG 
BeanUtilsBean : 
setProperty(com.rdc.struts.form.Manhours_searchresultForm@1148cfe, 
voList[1].khgs, [1]) javax.servlet.ServletException: BeanUtils.populate at 
org.apache.struts.util.RequestUtils.populate(RequestUtils.java:495) at 
org.apache.struts.action.RequestProcessor.processPopulate(RequestProcessor.java:
805) at 
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:203) at 
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1194) at 
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432) at 
javax.servlet.http.HttpServlet.service(HttpServlet.java:710) at 
javax.servlet.http.HttpServlet.service(HttpServlet.java:803) at 
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilt
erChain.java:290) at 
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.
java:206) at com.rdc.utf8.SysFilter.doFilter(SysFilter.java:28) at 
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilt
erChain.java:235) at 
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.
java:206) at 
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:2
33) at 
org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:1
75) 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:844) at 
org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Pr
otocol.java:583) at 
org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447) at 
java.lang.Thread.run(Thread.java:619) Caused by: java.lang.NullPointerException 
at 
org.apache.commons.beanutils.PropertyUtilsBean.getIndexedProperty(PropertyUtilsB
ean.java:427) at 
org.apache.commons.beanutils.PropertyUtilsBean.getIndexedProperty(PropertyUtilsB
ean.java:340) at 
org.apache.commons.beanutils.PropertyUtilsBean.getNestedProperty(PropertyUtilsBe
an.java:684) at 
org.apache.commons.beanutils.PropertyUtilsBean.getProperty(PropertyUtilsBean.jav
a:715) at 
org.apache.commons.beanutils.BeanUtilsBean.setProperty(BeanUtilsBean.java:884) 
at org.apache.commons.beanutils.BeanUtilsBean.populate(BeanUtilsBean.java:811) 
at org.apache.commons.beanutils.BeanUtils.populate(BeanUtils.java:298) at 
org.apache.struts.util.RequestUtils.populate(RequestUtils.java:493) ... 21 more

Answer 1

上边信息太乱了 重发
09:56:17,984 [http-8086-2] DEBUG BeanUtilsBean :   setProperty(com.rdc.struts.form.Manhours_searchresultForm@ea7545, voList[1].khgs, [1])
javax.servlet.ServletException: BeanUtils.populate
at org.apache.struts.util.RequestUtils.populate(RequestUtils.java:495)
at org.apache.struts.action.RequestProcessor.processPopulate(RequestProcessor.java:805)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:203)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1194)
at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:710)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.rdc.utf8.SysFilter.doFilter(SysFilter.java:28)
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:175)
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:844)
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)
Caused by: java.lang.NullPointerException
at org.apache.commons.beanutils.PropertyUtilsBean.getIndexedProperty(PropertyUtilsBean.java:427)
at org.apache.commons.beanutils.PropertyUtilsBean.getIndexedProperty(PropertyUtilsBean.java:340)
at org.apache.commons.beanutils.PropertyUtilsBean.getNestedProperty(PropertyUtilsBean.java:684)
at org.apache.commons.beanutils.PropertyUtilsBean.getProperty(PropertyUtilsBean.java:715)
at org.apache.commons.beanutils.BeanUtilsBean.setProperty(BeanUtilsBean.java:884)
at org.apache.commons.beanutils.BeanUtilsBean.populate(BeanUtilsBean.java:811)
at org.apache.commons.beanutils.BeanUtils.populate(BeanUtils.java:298)
at org.apache.struts.util.RequestUtils.populate(RequestUtils.java:493)
... 21 more

Answer 2

com.rdc.utf8.SysFilter.doFilter(SysFilter.java:28) 这个SysFilter类的代码检查一下
还有一个错误就是这个Caused by: java.lang.NullPointerException 

Answer 3

风怒了 居然发了两个一样的帖子我知道是NullPointerException的问题 不过不知道是在哪里？SysFilter是用来去乱码的 应该没什么关系

Answer 4

http://walnut.javaeye.com/blog/169559这个网址的代码写的有问题.
首先在PreAction 这个类中没有用session存放list.在页面上取到的值肯定是为空的.