SpringMVC 实现文件的上传与下载

缺乏、安全感 2021-06-11 15:12 490阅读 0赞

https://www.cnblogs.com/xuningchuanblogs/p/7683866.html

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

![复制代码][copycode.gif]

<%@ 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>

![复制代码][copycode.gif]

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
        }
    }

![复制代码][copycode.gif]

JSP界面：

![1217721-20171017203104865-1649633114.png][]

[copycode.gif]: /images/20210527/d0a324c3e5ec499bb4b43849c1fcbfc4.png
[1217721-20171017203104865-1649633114.png]: /images/20210527/ef2984d5298e47ecaf78b22c60e854ca.png