SpringMVC 实现文件的上传与下载

2023-08-08 19:38:34

一配置SpringMVC ,并导入与文件上传下载有关的jar包（在此不再赘述）

二新建相应 jsp 和controller

FileUpAndDown.jsp

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

    pageEncoding="UTF-8"%>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<html>

<head>

<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

<title>Insert title here</title>

</head>

<body>

<form action="${pageContext.request.contextPath}/fileUpLoad" method="post"  enctype="multipart/form-data">

文件名<input type="file" name="photo"/><br/>

     <input type="text" name="desc"/> <br/>

     <input type="submit" value="提交"/><br/>

</form>

<h3>童话镇.mp3  陈一发儿</h3>

<a href="${pageContext.request.contextPath}/fileDownLoad">前去下载</a>

</body>

</html>

package com.neuedu.controller;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.InputStream;

import java.io.OutputStream;

import java.util.UUID;

import javax.servlet.ServletContext;

import javax.servlet.http.HttpServletRequest;

import org.apache.commons.io.IOUtils;

import org.springframework.http.HttpHeaders;

import org.springframework.http.HttpStatus;

import org.springframework.http.ResponseEntity;

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RequestMethod;

import org.springframework.web.bind.annotation.RequestParam;

import org.springframework.web.multipart.commons.CommonsMultipartFile;

@Controller

public class FileUpAndDown {

    @RequestMapping(value="/fileUpLoad")

    public String testUpload(HttpServletRequest request,@RequestParam(value="desc",required=false) String desc,@RequestParam("photo") CommonsMultipartFile file) throws Exception{

        ServletContext servletContext = request.getServletContext();//获取ServletContext的对象 代表当前WEB应用

        String realPath = servletContext.getRealPath("/uploads");//得到文件上传目的位置的真实路径

        System.out.println("realPath :"+realPath);

        File file1 = new File(realPath);

        if(!file1.exists()){

            file1.mkdir();   //如果该目录不存在，就创建此抽象路径名指定的目录。

        }

        String prefix = UUID.randomUUID().toString();

        prefix = prefix.replace("-","");

        String fileName = prefix+"_"+file.getOriginalFilename();//使用UUID加前缀命名文件，防止名字重复被覆盖

        InputStream in= file.getInputStream();;//声明输入输出流

        OutputStream out=new FileOutputStream(new File(realPath+"\\"+fileName));//指定输出流的位置;

        byte []buffer =new byte[1024];

        int len=0;

        while((len=in.read(buffer))!=-1){

            out.write(buffer, 0, len);

            out.flush();                //类似于文件复制，将文件存储到输入流，再通过输出流写入到上传位置

        }                               //这段代码也可以用IOUtils.copy(in, out)工具类的copy方法完成

        out.close();

        in.close();

        return "success";

    }

    @RequestMapping("/fileDownLoad")

    public ResponseEntity<byte[]> fileDownLoad(HttpServletRequest request) throws Exception{

      ServletContext servletContext = request.getServletContext();

      String fileName="童话镇.mp3";

      String realPath = servletContext.getRealPath("/WEB-INF/"+fileName);//得到文件所在位置

        InputStream in=new FileInputStream(new File(realPath));//将该文件加入到输入流之中

         byte[] body=null;

         body=new byte[in.available()];// 返回下一次对此输入流调用的方法可以不受阻塞地从此输入流读取（或跳过）的估计剩余字节数

         in.read(body);//读入到输入流里面

        fileName=new String(fileName.getBytes("gbk"),"iso8859-1");//防止中文乱码

        HttpHeaders headers=new HttpHeaders();//设置响应头

        headers.add("Content-Disposition", "attachment;filename="+fileName);

        HttpStatus statusCode = HttpStatus.OK;//设置响应吗

        ResponseEntity<byte[]> response=new ResponseEntity<byte[]>(body, headers, statusCode);

        return response;

        //public ResponseEntity（T  body，

        //                       MultiValueMap < String，String > headers，

        //                       HttpStatus  statusCode）

        //HttpEntity使用给定的正文，标题和状态代码创建一个新的。

        //参数：

        //body - 实体机构

        //headers - 实体头

        //statusCode - 状态码

    }

}