首先在首页添加下载文件的功能选项：
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8" %>
<!DOCTYPE HTML>
<html>
<head>
<title>初始页面</title>
</head>
<body>
<h3>
<a href="${pageContext.request.contextPath}/Log/gologin">登录页面</a>
</h3>
<h3>
<a href="${pageContext.request.contextPath}/Log/main">进入首页</a>
</h3>
<h3>
<a href="${pageContext.request.contextPath}/Upload/goinput">文件上传</a>
</h3>
<h3>
<a href="${pageContext.request.contextPath}/Upload/godownload">文件下载</a>
</h3>
</body>
</html>
然后在Controller中写请求：
//跳转到下载文件界面
@RequestMapping("/godownload")
public String godownloads(){
return "download";
}
//下载文件
@RequestMapping("/download")
public String downloads(HttpServletResponse response , HttpServletRequest request) throws Exception{
//要下载的图片地址
String path = request.getServletContext().getRealPath("input");
String fileName = "Java开发学习路线.png";
//设置response响应头
response.reset();
response.setCharacterEncoding("UTF-8");
response.setContentType("multipart/form-data");
//设置响应头
response.setHeader("Content-Disposition","attachment;fileName="+
URLEncoder.encode(fileName, StandardCharsets.UTF_8));
File file = new File(path,fileName);
//读取文件-输出流
InputStream inputStream = new FileInputStream(file);
//写文件-输出流
OutputStream outputStream = response.getOutputStream();
byte[] buff = new byte[1024];
int index = 0;
//执行写出操作
while ((index=inputStream.read(buff))!=-1){
outputStream.write(buff,0,index);
outputStream.flush();
}
outputStream.close();
inputStream.close();
return "downloadSuccess";
}
规定了要下载文件的路径以及文件名，更换要下载的文件只需要改动这部分即可。
然后写发送下载请求的页面：
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%--
Created by IntelliJ IDEA.
User: shadowpee
Date: 2021/1/25
Time: 23:47
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Title</title>
</head>
<body>
<a href="${pageContext.request.contextPath}/Upload/download">下载图片</a>
<a href="${pageContext.request.contextPath}">回到首页</a>
</body>
</html>
打开Tomcat服务器试验一下：
点击文件下载，跳转到下载文件界面
点击发送下载请求：
下载成功，回到首页。