springmvc 实现文件上传下载，demo直接可用

package cn.com.zwz.spring.beans.file;

import org.apache.commons.io.FileUtils;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.multipart.MultipartFile;


import javax.annotation.Resource;
import javax.servlet.annotation.MultipartConfig;
import javax.servlet.http.HttpServletRequest;

import java.io.*;
import java.net.URLEncoder;
import java.util.List;



@Controller
@RequestMapping("/file")
@MultipartConfig(location="/tmp", fileSizeThreshold=1024*1024,
        maxFileSize=1024*1024*5, maxRequestSize=1024*1024*5*5)
public class Load {

    @Resource
    HttpServletRequest request;


    /**
     * @return  返回相对路径RelativePath
     */
    public String RelPath() {
        String path = request.getContextPath();
        return request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
    }

    /**
     * @return  返回服务器目录的真实路径
     */
    public String RealPath() {
        return request.getSession().getServletContext().getRealPath("/");
    }


    @RequestMapping("/toUpload")
    public Object toUpload(){

        return "fileupload";
    }


    @RequestMapping("/upload")
    public Object upload(@RequestParam("uploadfile") List uploadfile){
        if (!uploadfile.isEmpty() && uploadfile.size() > 0) {
            for (MultipartFile file : uploadfile) {
                String originalFilename = file.getOriginalFilename();
                String dirPath = request.getServletContext().getRealPath("/upload/");
                File filePath = new File(dirPath);
                if (!filePath.exists()) {
                    filePath.mkdirs();
                }

                String newFilename = "_" + originalFilename;
                try {
                    file.transferTo(new File(dirPath + "_"+newFilename));
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }
            return "sucess";

    }

    @RequestMapping("/toDownload")
    public Object toDownload(){

        return "filedownload";
    }

    /**
     * 文件下载
     * ResponseEntity：该类实现响应头、文件数据（以字节存储）、状态封装在一起交给浏览器处理以实            
       现浏览器的文件下载
     * 

     * ResponseEntity 也可作为响应数据使用  与@ResponseBody 注解功能相似
     * 但是ResponseEntity的优先级高于@ResponseBody
     * 在不是ResponseEntity的情况下才去检查有没有@ResponseBody注解。
     * 如果响应类型是ResponseEntity可以不写@ResponseBody注解，写了也没有关系。
     * 

     * 简单粗暴的讲，个人理解：
     *      @ResponseBody可以直接返回Json结果，
     *      @ResponseEntity不仅可以返回json结果，还可以定义返回的HttpHeaders和HttpStatus
     */
    @RequestMapping("/download")
    public ResponseEntity download(String filename) throws Exception {
        String path = request.getServletContext().getRealPath("/");
        File file = new File(path+File.separator+filename);
        /*filename = this.getFilename(request,filename);
        HttpHeaders headers = new HttpHeaders();
        headers.setContentDispositionFormData("attachment",filename);
        headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
        return new ResponseEntity<>(FileUtils.readFileToByteArray(file),headers, HttpStatus.OK);*/

        if(file.exists()){
            HttpHeaders headers = new HttpHeaders();
            headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
            headers.setContentDispositionFormData("attachment", file.getName());
            return new ResponseEntity(FileUtils.readFileToByteArray(file),headers,HttpStatus.OK);
        }else{
            System.out.println("文件不存在,请重试...");
            return null;
        }

    }


    public String getFilename(HttpServletRequest request,String filename) throws Exception{
        String[] IEBrowserKeyWord = {"MSIE","Trident","Edge"};
        String userAgent = request.getHeader("User-Agent");
        for(String keyWord:IEBrowserKeyWord){
            if(userAgent.contains(keyWord)){
                return URLEncoder.encode(filename,"UTF-8");
            }
        }
        return new String(filename.getBytes("UTF-8"),"ISO-8859-1");
    }
}

jsp代码:

filedownload.jsp:

<%@ page contentType="text/html;charset=UTF-8" language="java" pageEncoding="UTF-8" %>
<%@ page import="java.net.URLEncoder" %>


    
    


">文件下载

fileupload.jsp:

<%@ page contentType="text/html;charset=UTF-8" language="java" %>


    
    


<%--enctype="multipart/form-data"采用二进制流处理表单数据--%>

    请选择文件：

    <%--multiple属性选择多个文件上传--%>
    

springmvc.xml配置