<SCRIPT LANGUAGE="JavaScript">

function CheckForm(){
    if(isEmpty(trim(document.submitForm.name.value))){
        alert("对不起!请您填入专题名称。");
        document.submitForm.name.focus();
        return false;
    }
    if(isEmpty(trim(document.submitForm.alias.value))){
        alert("对不起!请您填入专题别名。");
        document.submitForm.alias.focus();
        return false;
    }
    if(isEmpty(trim(document.submitForm.picture.value))){
        alert("请选择图片！");
        document.submitForm.picture.focus();
        return false;
    }
    
    submitForm.submit();
}

</SCRIPT>

<form name="submitForm" action="special.do" method="post" enctype="multipart/form-data">
  <input type="file" name="picture" size="35"> 
   <a href="#" onclick="CheckForm()"><img src="../../image/2_buttom01.gif" title="上传" width="59" height="19" border=0></a> 
</form>

java.lang.IllegalArgumentException: argument type mismatch
    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.commons.beanutils.PropertyUtils.setSimpleProperty(PropertyUtils.java:1789)
    at org.apache.commons.beanutils.PropertyUtils.setNestedProperty(PropertyUtils.java:1684)
    at org.apache.commons.beanutils.PropertyUtils.setProperty(PropertyUtils.java:1713)
    at org.apache.commons.beanutils.BeanUtils.setProperty(BeanUtils.java:1019)
    at org.apache.commons.beanutils.BeanUtils.populate(BeanUtils.java:808)
    at org.apache.struts.util.RequestUtils.populate(RequestUtils.java:1252)
    at org.apache.struts.action.RequestProcessor.processPopulate(RequestProcessor.java:821)
    at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:254)
    at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1482)
    at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:525)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:647)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
    at com.websh.esp.common.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:80)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:172)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
    at org.apache.c