I want to upload a file in struts2,my jsp file is follows: <html:html> <body> <s:form enctype="multipart/form-data" method="post" action="upload.action"> <s:file id="uploadFile" name="uploadFile" accept="text/*"/> <input type="submit"> </s:form> </body> </html:html>
my action is follows: import java.io.File; private File uploadFile; public File getUploadFile(){ return uploadFile; } public void setUploadFile(File uploadFile){ this.uploadFile=uploadFile; } public String upload() throws Exception{ request=ServletActionContext.getRequest(); return SUCCESS; } when I run above code,it shows following error: 2008-12-14 23:45:45 com.opensymphony.xwork2.interceptor.ParametersInterceptor setParameters Fatal: ParametersInterceptor - [setParameters]: Unexpected Exception caught setting 'uploadFileContentType' on 'class demo.TestAction: Error setting expression 'uploadFileContentType' with value '[Ljava.lang.String;@80a22' 2008-12-14 23:45:45 com.opensymphony.xwork2.interceptor.ParametersInterceptor setParameters Fatal: ParametersInterceptor - [setParameters]: Unexpected Exception caught setting 'uploadFileFileName' on 'class demo.TestAction: Error setting expression 'uploadFileFileName' with value '[Ljava.lang.String;@1d159e4 I have no 'uploadFileContentType' and 'uploadFileFileName' in my JSP,why raise 'uploadFileContentType' and 'uploadFileFileName' error? How to correct my above code? Thanks in advance!