struts2上传文件

<form class="form-horizontal" onkeydown="if(event.keyCode==13)return false;" action="/user/updatePro.do" method="post"
      role="form" id="updateUserForm" enctype="multipart/form-data">
    <input type="hidden" name="id" value="${user.id}">
    
    <div class="form-group">
        <label for="pic" class="col-sm-2 control-label">头像</label>
        <div class="col-sm-4">
            <input type="file" name="pic2" id="pic" />
        </div>
    </div>
    <div class="form-group">
        <div class="col-sm-offset-2 col-sm-10">
            <button type="submit" class="btn btn-default" id="updateUserBtn">修改</button>
        </div>
    </div>
</form>

package cn.getword.action;

import cn.getword.domain.User;
import cn.getword.service.UserService;
import com.opensymphony.xwork2.ActionSupport;
import com.opensymphony.xwork2.ModelDriven;

import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.commons.io.FileUtils;

import org.apache.struts2.ServletActionContext;
import org.apache.struts2.convention.annotation.Action;
import org.apache.struts2.convention.annotation.Namespace;
import org.apache.struts2.convention.annotation.ParentPackage;
import org.apache.struts2.convention.annotation.Result;
import org.apache.struts2.dispatcher.multipart.MultiPartRequestWrapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;

import javax.servlet.http.HttpServletRequest;
import java.io.File;
import java.io.IOException;
import java.time.LocalDate;
import java.util.*;

@Controller
@ParentPackage("my-default")
@Namespace("/user")
public class UserAction extends ActionSupport implements ModelDriven<User> {
    @Autowired
    private UserService userService;
    private User user = new User();
    private String pic2FileName;  // 获取原始文件名，同理可以获取文件File



    @Action(value = "update", results = {@Result(location = "/WEB-INF/views/updateUser.jsp")})
    public String updateUser() {
        HttpServletRequest request = ServletActionContext.getRequest();
        User user1 = userService.getUserById(user.getId());
        request.setAttribute("user", user1);
        return SUCCESS;
    }


    @Action(value = "updatePro", results = {@Result(name = "success", type = "redirect", location = "/index.do"),
            @Result(name = "input", type = "redirect", location = "/index.do")
    })
    public String updateUserPro() {
        HttpServletRequest request = ServletActionContext.getRequest();

        String pic = request.getParameter("pic2");
        if (ServletFileUpload.isMultipartContent(request)) {
            File[] pics = ((MultiPartRequestWrapper) request).getFiles("pic2");
            if (pics.length > 0) {
                File file = pics[0];
                String path = "/upload/images/user";
                LocalDate now = LocalDate.now();
                path += "/" + now.getYear() + now.getMonthValue() + now.getDayOfMonth();
                File dir = new File(request.getServletContext().getRealPath(path));
                if (!dir.exists()) {
                    dir.mkdirs();
                }

                String filename = file.getName();

                String ext = filename.substring(filename.lastIndexOf(".") + 1);
                //判断是否需要覆盖
                User u1 = userService.getUserById(user.getId());
                String filepath = u1.getPic(); //虚拟目录
                if (user.getPic() == null) {
                    filepath = path + "/" + UUID.randomUUID().toString().replace("-", "") +"."+ ext;
                    user.setPic(filepath);
                }

                File uploadFile = new File(request.getServletContext().getRealPath(filepath));  //目标路径
                try {
                    FileUtils.copyFile(file, uploadFile);
                } catch (IOException e) {
                    e.printStackTrace();
                }
                rs = userService.updateUser(user);
            }

            return SUCCESS;
        }
        return INPUT;
    }
    //======================
    @Override
    public User getModel() {
        return user;
    }
    public void setUserService(UserService userService) {
        this.userService = userService;
    }
    public String getPic2FileName() {
        return pic2FileName;
    }
    public void setPic2FileName(String pic2FileName) {
        this.pic2FileName = pic2FileName;
    }
}