创建Web项目，导入相关JAR包；
<dependency>
<groupId>commons-fileupload</groupId>
<artifactId>commons-fileupload</artifactId>
<version>1
.4</version>
</dependency>
<!-- https://mvnrepository
.com/artifact/commons-io/commons-io -->
<dependency>
<groupId>commons-io</groupId>
<artifactId>commons-io</artifactId>
<version>2
.11
.0</version>
</dependency>
创建并配置web
.xml文件；
<?xml version="1
.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns
.jcp
.org/xml/ns/javaee"
xmlns:xsi="http://www
.w3
.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns
.jcp
.org/xml/ns/javaee http://xmlns
.jcp
.org/xml/ns/javaee/web-app_4_0
.xsd"
version="4
.0">
<servlet>
<servlet-name>Springmvc</servlet-name>
<servlet-class>org
.springframework
.web
.servlet
.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:SpringMVC
.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>Springmvc</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
</web-app>
添加用于上传的jsp页面；
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<%@ taglib uri="http://java
.sun
.com/jsp/jstl/core" prefix="c"%>
<!DOCTYPE html>
<html>
<head>
<title>文件上传</title>
</head>
<body>
<table border="1">
<tr>
<td width="500" align="center">文件上传</td>
</tr>
<tr>
<td>
<form action="${pageContext
.request.contextPath}/file/upload"
method="post" enctype="multipart/form-data">
<input type="file" name="uploadfiles" multiple="multiple"/><br>
<input type="submit" value="上传"><br>
</form>
</td>
</tr>
<c:forEach items="${msgs}" var="msg">
<tr><td align="center" colspan="2" style="color: red">${msg}</td></tr>
</c:forEach>
</table>
</body>
</html>
创建控制类用于上传文件；
package com
.springmvc
.controller;
import java
.io
.File;
import java
.io
.IOException;
import java
.util
.ArrayList;
import javax
.servlet
.http
.HttpServlet
Request;
import org
.springframework
.stereotype
.Controller;
import org
.springframework
.web
.bind
.annotation
.RequestMapping;
import org
.springframework
.web
.multipart
.MultipartFile;
@Controller
@
RequestMapping("/file")
public class FileUploadController {
@
RequestMapping("/upload")
public String fileUpload(ArrayList<MultipartFile> uploadfiles, HttpServlet
Request request) {
//定义列表msgs保存提示信息
ArrayList<String> msgs = new ArrayList<>
();
if (uploadfiles
.get(0)
.getSize
() > 0) { //判断是否上传文件
for (MultipartFile file : uploadfiles) { //循环获取文件
//判断文件不为空且大小大于0
if (!file
.isEmpty
() & file
.getSize
() > 0) {
//获取文件原始名称
String originalFilename = file
.getOriginalFilename
();
//获取服务器中的文件夹路径
String path =
request.getServletContext().getRealPath("/upload/");
//设置文件保存到服务器的目标路径
String filePath = path + originalFilename;
try {
//保存文件内容到目标路径
file
.transferTo(new File(filePath));
} catch (IOException e) {
msgs
.add(filePath + "保存失败");
}
msgs
.add(filePath +"保存成功");
}
}
}
else
msgs
.add("上传文件失败");
request.setAttribute("msgs", msgs);
return "fileUpload";
}
}
添加配置文件；
<?xml version="1
.0" encoding="UTF-8"?>
<beans xmlns="http://www
.springframework
.org/schema/beans"
xmlns:xsi="http://www
.w3
.org/2001/XMLSchema-instance"
xmlns:context="http://www
.springframework
.org/schema/context"
xmlns:mvc="http://www
.springframework
.org/schema/mvc"
xsi:schemaLocation="http://www
.springframework
.org/schema/beans http://www
.springframework
.org/schema/beans/spring-beans
.xsd http://www
.springframework
.org/schema/context https://www
.springframework
.org/schema/context/spring-context
.xsd http://www
.springframework
.org/schema/mvc https://www
.springframework
.org/schema/mvc/spring-mvc
.xsd">
<context:component-scan base-package="com
.springmvc
.controller"/>
<mvc:annotation-driven />
<bean id="viewResolver" class="org
.springframework
.web
.servlet
.view
.InternalResourceViewResolver">
<property name="prefix" value="/WEB-INF/pages/"/>
<property name="suffix" value="
.jsp"/>
</bean>
<!--配置视图控制器，指定文件上传页面的映射路径-->
<mvc:view-controller path="/file/fileupload" view-name="fileUpload"/>
<mvc:view-controller path="/file/filedownload" view-name="fileDownload"/>
<!--配置注解驱动-->
<mvc:annotation-driven/>
<!--配置文件上传解析器-->
<bean id="multipartResolver"
class="org
.springframework
.web
.multipart
.commons
.CommonsMultipartResolver">
<!--指定请求的编码方式-->
<property name="defaultEncoding" value="UTF-8"></property>
<!--指定允许上传文件的大小，此处设置最大值为1 M，单位为字节-->
<property name="maxUploadSize" value="1024000"></property>
</bean>
</beans>
添加上传成功的消息页面。
文件下载：
创建控制器类：
package com
.springmvc
.controller;
import java
.io
.File;
import java
.io
.IOException;
import java
.net
.URLEncoder;
import javax
.servlet
.http
.HttpServlet
Request;
import org
.apache
.commons
.io
.FileUtils;
import org
.springframework
.http
.HttpHeaders;
import org
.springframework
.http
.HttpStatus;
import org
.springframework
.http
.MediaType;
import org
.springframework
.http
.ResponseEntity;
import org
.springframework
.stereotype
.Controller;
import org
.springframework
.web
.bind
.annotation
.RequestMapping;
@Controller
@
RequestMapping("/file")
public class FileDownloadController {
@
RequestMapping("/download")
public ResponseEntity<byte[]> FileDownload(HttpServlet
Request request, String fileName)
throws IOException {
//获取下载文件的路径
String filepath =
request.getServletContext().getRealPath("/upload/") + fileName;
//创建该文件的对象
File file = new File(filepath);
//将文件读取到字节数组中
byte[] bytes = FileUtils
.readFileToByteArray(file);
//创建HttpHeaders对象设置响应头信息
HttpHeaders headers = new HttpHeaders
();
//设置浏览器以“UTF-8”编码方式显示文件名
fileName = URLEncoder
.encode(fileName, "UTF-8");
//设置以下载的方式打开文件，并指定文件名称
headers
.setContentDispositionFormData("attachment", fileName);
//设置文件的下载方式为二进制流
headers
.setContentType(MediaType
.APPLICATION_OCTET_STREAM);
return new ResponseEntity<>(bytes, headers, HttpStatus
.OK);
}
}
添加用于上传的jsp页面；
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<title>文件下载</title>
</head>
<body>
<table border="1">
<tr>
<td width="350" align="center">下载列表</td>
</tr>
<tr>
<td>
<a href="${pageContext
.request.contextPath}/file/download?fileName=微信图片_20250612231528
.jpg">
这是一张图片</a><br>
</td>
</tr>
</table>
</body>
</html>
实验成果：
修改一下
本文介绍了两种获取Web应用绝对路径的方法：使用request.getRealPath()和getServlet().getServletContext().getRealPath(/).前者已被标记为不推荐使用，后者是推荐的替代方案。
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