springMVC实现文件上传和下载

本文实例为大家分享了springMVC实现文件上传和下载的具体代码，供大家参考，具体内容如下

1准备工作

web.xml文件导入DispatcherServlet，CharacterEncodingFilter

        springmvc
        org.springframework.web.servlet.DispatcherServlet

        
            contextConfigLocation
            classpath:applicationContext.xml
        
        1
    
    
        springmvc
        /
    


    
        encoding
        org.springframework.web.filter.CharacterEncodingFilter
        
            encoding
            utf-8
        
    
    
        encoding
        /*

前端测试页面

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

  
    
  
  
  <%--  必须将表单的method设置为POST--%>
  <%--  设置enctype属性为multipart/form-data，二进制传递数据--%>
  

    
    
  
  

  点击下载
  

spring配置文件applicationContext.xml

2.文件上传

controller

package com.zky.controller;

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

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.net.URLEncoder;

@Controller
public class FileController {
    //@RequestParam("file") 将name=file控件得到的文件封装成CommonsMultipartFile 对象
    //批量上传CommonsMultipartFile则为数组即可
    @RequestMapping("/upload")
    public String fileUpload(@RequestParam("file") CommonsMultipartFile file , HttpServletRequest request) throws IOException {

        //获取文件名 : file.getOriginalFilename();
        String uploadFileName = file.getOriginalFilename();

        //如果文件名为空，直接回到首页！
        if ("".equals(uploadFileName)){
            return "redirect:/index.jsp";
        }
        System.out.println("上传文件名 : "+uploadFileName);

        //上传路径保存设置
        String path = request.getServletContext().getRealPath("/upload");
        //如果路径不存在，创建一个
        File realPath = new File(path);
        if (!realPath.exists()){
            realPath.mkdir();
        }
        System.out.println("上传文件保存地址："+realPath);

        InputStream is = file.getInputStream(); //文件输入流
        OutputStream os = new FileOutputStream(new File(realPath,uploadFileName)); //文件输出流

        //读取写出
        int len=0;
        byte[] buffer = new byte[1024];
        while ((len=is.read(buffer))!=-1){
            os.write(buffer,0,len);
            os.flush();
        }
        os.close();
        is.close();
        return "redirect:/index.jsp";
    }
}

采用file.Transto 来保存上传的文件

/*
     * 采用file.Transto 来保存上传的文件
     */
    @RequestMapping("/upload2")
    public String  fileUpload2(@RequestParam("file") CommonsMultipartFile file, HttpServletRequest request) throws IOException {

        //上传路径保存设置
        String path = request.getServletContext().getRealPath("/upload");
        File realPath = new File(path);
        if (!realPath.exists()){
            realPath.mkdir();
        }
        //上传文件地址
        System.out.println("上传文件保存地址："+realPath);

        //通过CommonsMultipartFile的方法直接写文件（注意这个时候）
        file.transferTo(new File(realPath +"/"+ file.getOriginalFilename()));

        return "redirect:/index.jsp";
    }

3.文件下载 

@RequestMapping(value="/download")
    public String downloads(HttpServletResponse response , HttpServletRequest request) throws Exception{
        //要下载的图片地址，改为自己图片路径,我是下载在我的项目里面的
        String  path = request.getServletContext().getRealPath("/upload");
        //文件名
        String  fileName = "新建文本文档.txt";

        //1、设置response 响应头
        response.reset(); //设置页面不缓存,清空buffer
        response.setCharacterEncoding("UTF-8"); //字符编码
        response.setContentType("multipart/form-data"); //二进制传输数据
        //设置响应头
        response.setHeader("Content-Disposition",
                "attachment;fileName="+ URLEncoder.encode(fileName, "UTF-8"));

        File file = new File(path,fileName);
        //2、 读取文件--输入流
        InputStream input=new FileInputStream(file);
        //3、 写出文件--输出流
        OutputStream out = response.getOutputStream();

        byte[] buff =new byte[1024];
        int index=0;
        //4、执行 写出操作
        while((index= input.read(buff))!= -1){
            out.write(buff, 0, index);
            out.flush();
        }
        out.close();
        input.close();
        return null;
    }

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。