<form action="test/upload.action" method="post" enctype="multipart/form-data">
        <input type="file" name="upload"><br/>
        <input type="submit" value="上传">
   </form>
          注意：此处设置form表单enctype="multipart/form-data"属性

 public class UploadFile extends ActionSupport {
 private File upload;

 private String uploadFileName;

 public File getUpload() {
  return upload;
 }

 public void setUpload(File upload) {
  this.upload = upload;
 }

 public String getUploadFileName() {
  return uploadFileName;
 }

 public void setUploadFileName(String uploadFileName) {
  this.uploadFileName = uploadFileName;
 }

 public String execute() throws Exception {
    String parentFilepath = ServletActionContext.getServletContext()
     .getRealPath("/upload");// 获取当前服务器目录真实路径 upload是存放上传文件的文件夹
   System.out.println(parentFilepath + "--parent filepath--");
   File parentFile = new File(parentFilepath);// 构造upload目录
   System.out
     .println(this.getUploadFileName() + "--upload filename--");
   File uploadFile = new File(parentFile, this.getUploadFileName());// 通过upload目录和文件名构建目标文件
   if (!parentFile.exists())
    parentFile.mkdir();// 如果upload目录不存在 则创建一个目录
   FileUtils.copyFile(this.getUpload(), uploadFile);// 将要上传的文件复制到目标文件
   return SUCCESS;

 }
}

<action name="upload" class="hxlzp.uploadfile.UploadFile">
   <result name="success">/index1.jsp</result>
   </action>

   <img alt="" src="upload/<s:property value ="uploadFileName" /> ">

此处只是简单的实现了struts2中文件上传的功能 可以实现文件上传类型的设置