除了文件的上传我们还需要从磁盘下载
实现文件的下载只要编写一个控制器，完成读写操作和响应头和数据类型的设置就可以了
下面演示的是从G盘imgs文件夹中下载文件
具体代码如下
1 package com.cqupt.dayday;
2
3 import org.springframework.stereotype.Controller;
4 import org.springframework.web.bind.annotation.RequestMapping;
5
6 import javax.servlet.http.HttpServletRequest;
7 import javax.servlet.http.HttpServletResponse;
8 import java.io.*;
9
10 /**
11 * Created by I am master on 2017/5/16.
12 */
13 @Controller
14 public class ResourceController {
15 @RequestMapping("/download")
16 public String download(String fileName, HttpServletRequest request, HttpServletResponse response) throws IOException {
17 response.setCharacterEncoding("utf-8");
18 //返回的数据类型
19 response.setContentType("application/pdf");
20 //响应头
21 response.setHeader("Content-Disposition", "attachment;fileName="
22 + fileName);
23 InputStream inputStream=null;
24 OutputStream outputStream=null;
25 //路径
26 String path ="G:"+ File.separator+"imgs"+File.separator;
27 byte[] bytes = new byte[2048];
28 try {
29 File file=new File(path,fileName);
30 inputStream = new FileInputStream(file);
31 outputStream = response.getOutputStream();
32 int length;
33 //inputStream.read(bytes)从file中读取数据,-1是读取完的标志
34 while ((length = inputStream.read(bytes)) > 0) {
35 //写数据
36 outputStream.write(bytes, 0, length);
37 }
38 } catch (FileNotFoundException e) {
39 e.printStackTrace();
40 } catch (IOException e) {
41 e.printStackTrace();
42 }finally {
43 //关闭输入输出流
44 if(outputStream!=null) {
45 outputStream.close();
46 }
47 if(inputStream!=null) {
48 inputStream.close();
49 }
50 }
51 return null;
52 }
53 }
用了注解进行描述就不在重复了
在写的过程中遇到的问题:FileNotFoundException
原因：路径不正确
一定要注意路径问题在写的时候
前端代码：
1 <%@ page contentType="text/html;charset=UTF-8" language="java" %> 2 <html> 3 <head> 4 <title>Title</title> 5 </head> 6 <body> 7 <center><h1>Download Page</h1></center> 8 <a href="download?fileName=B.pdf">B.pdf</a> 9 </body> 10 </html>
测试页面：
点击即完成下载
时间： 2024-10-06 20:45:25