1、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>2、后端代码
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
}
}