表单文件域上传 HTTP Status500 服务器遇到了一个内部错误（）阻止了它执行此请求

 package com.controller;

import java.io.File;
import java.io.IOException;
import java.io.OutputStream;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;


import org.apache.commons.io.FileUtils;

import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.multipart.commons.CommonsMultipartFile;

@Controller
public class FileUploadController {


    @RequestMapping("/fileupload")
public String shangchuan(
        @RequestParam(value = "file", required = false) CommonsMultipartFile file,
        HttpServletRequest request, ModelMap map) {
    String path = request.getRealPath("upload");
    String fileName = file.getOriginalFilename();
    System.out.println(path + "/" + fileName);
    File f = new File(path, fileName);

    try {
        file.transferTo(f);
    } catch (IllegalStateException e) {
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    request.setAttribute("picUrl", "upload/" + fileName);
    return "upload.jsp";

}

public static void downLoadFile(HttpServletResponse response, File file) {
    if (file == null || !file.exists()) {
        return;
    }
    OutputStream out = null;
    try {
        response.reset();
        response.setContentType("application/octet-stream; charset=utf-8");
        response.setHeader("Content-Disposition", "attachment; filename="
                + file.getName());
        out = response.getOutputStream();
        out.write(FileUtils.readFileToByteArray(file));
        out.flush();
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        if (out != null) {
            try {
                out.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}
@RequestMapping("download2.do")
public String  xiazai(HttpServletRequest request,HttpServletResponse  response){
  String fileName= request.getRealPath("/upload");
    fileName+="/460.gif"; 
    File file=new File(fileName);
  downLoadFile(response, file);

    return null;
}

}

     <form action="fileupload" method="post">
    <input type="file" name = "file">
    <input type="submit" value="UPLOAD">



    </form>

form 里面添加 enctype="multipart/form-data" ，你是文件上传，要以二进制传过去。