金山老师的笔记13. 文件的上传下载
13.1. 创建项目
13.2. 添加依赖,修改pom.xml
添加common-fileupload(Apache)类库,从request中解析出文件内容
xml
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
<!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.0.1</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>5.2.4.RELEASE</version>
</dependency>
<!-- https://mvnrepository.com/artifact/commons-fileupload/commons-fileupload -->
<dependency>
<groupId>commons-fileupload</groupId>
<artifactId>commons-fileupload</artifactId>
<version>1.4</version>
</dependency>13.3. 前端控制器(web.xml)
xml
<!DOCTYPE web-app PUBLIC
"-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
"http://java.sun.com/dtd/web-app_2_3.dtd" >
<web-app>
<display-name>Archetype Created Web Application</display-name>
<!--前端控制器-->
<servlet>
<servlet-name>DispatcherServlet</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<!--默认的配置文件的名字applicationContext.xml-->
<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>DispatcherServlet</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
</web-app>13.4. 配置multipartResolver
Springmvc.xml中配置使用什么类型的库解析request中的文件内容
1）使用Servlet原生的方式
2）common-fileupload
在springmvc中声明multipartResolver
xml
<?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
https://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.neuedu.mvc"></context:component-scan>
<mvc:annotation-driven/>
<!-- 使用Common-fileupload包解析 上传的文件 -->
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver" />
</beans>13.5. 创建上传文件的表单
上传文件时form表单要求： 1 ）method ： post 2 ）enctype: multipart/form-data
<%--
Created by IntelliJ IDEA.
User: root
Date: 2020/4/1
Time: 9:00
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" isELIgnored="false" %>
<html>
<head>
<title>上传</title>
</head>
<body>
<!--
上传文件时form表单要求：
1 method ： post
2 enctype: multipart/form-data
-->
<form action="${pageContext.request.contextPath}/upload_file" method="post" enctype="multipart/form-data">
上传文件1:<input type="file" name="myfile" /><br/>
上传文件2:<input type="file" name="myfile" /><br/>
<input type="submit" value="上传"/>
</forma>
</body>
</html>xml
!--指定使用common-fileupload类型的方式解析request中的文件内容-->
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
<!--设置允许上传的最大多少字节 -->
<property name="maxUploadSize" value="2000"></property>
</bean>13.6. 上传功能
1)将表单中的文件持久化的保存到服务器硬盘中,
2)记录到数据库中。
1 xxx 2020年4月1日08:43:35 96530565d35746b19bf5a5ee3251fdf8.txt a.txt
2 xxx 2020年4月1日08:43:35 86530565d35746b19bf5a5ee3251fdf8.txt a.txt
3 xxx 2020年4月1日08:43:35 76530565d35746b19bf5a5ee3251fdf8.txt b.txt
4 xxx 2020年4月1日08:43:35 66530565d35746b19bf5a5ee3251fdf8.txt ctxt
5 xxx 2020年4月1日08:43:35 596c08719709471697d0c39df87f8d6f.txt d.txt
java
package com.neuedu.mvc;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.multipart.MultipartFile;
import java.io.File;
import java.io.IOException;
import java.util.UUID;
/**
* 项目： spring-framework
* 类名: FileController
* 创建时间： 2024/3/21 15：42
* 描述 :
* 作者 : 张金山
* QQ : 314649444
* Site: https://jshand.gitee.io
*/
@Controller
public class FileController {
public static final String UPLOAD_DIR = "D:\\upload";
/**
* http://127.0.0.1:8080/mvc/test
*
* @return
*/
@ResponseBody
@RequestMapping("test")
String test(){
return "success";
}
@RequestMapping("toupload")
String toupload(){
return "/upload.jsp";
}
@RequestMapping("upload_file")
String uploadFile(MultipartFile myfile) throws IOException {
String name = myfile.getName();
String originalFilename = myfile.getOriginalFilename();
long size = myfile.getSize();
System.out.println("name = " + name);
// a.jpg doc
System.out.println("originalFilename = " + originalFilename);
// jpg doc
String ext = originalFilename.substring(originalFilename.lastIndexOf("."));
System.out.println("size = " + size);
//将文件从临时目录转出到 dist目标为止
//D:\\upload\\唯一的xxxxx.jpg
String uuid =UUID.randomUUID().toString().replace("-","");
String newFileName = uuid + ext;
File dist = new File(UPLOAD_DIR,newFileName);
myfile.transferTo(dist);
return "redirect:/list_file";
}
@RequestMapping("list_file")
public String listFile(Model model){
File dir = new File(UPLOAD_DIR);
File[] files = dir.listFiles();
model.addAttribute("files",files);
return "/file_list.jsp";
}
}html
<%--
Created by IntelliJ IDEA.
User: root
Date: 2020/4/1
Time: 9:00
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" isELIgnored="false" %>
<html>
<head>
<title>上传</title>
</head>
<body>
<!--
上传文件时form表单要求：
1 method ： post
2 enctype: multipart/form-data
-->
html
<%--
Created by IntelliJ IDEA.
User: Administrator
Date: 2024/3/21
Time: 16:17
To change this template use File | Settings | File Templates.
--%>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Title</title>
</head>
<body>
<table cellpadding="0" cellspacing="0" border="1">
<tr>
<td> 序号 </td>
<td> 文件名（硬盘中的） </td>
<td> 大小 </td>
</tr>
<c:forEach items="${files}" var="file" varStatus="status">
<tr>
<td> ${status.count} </td>
<td> ${file.name} </td>
<td> ${file.totalSpace}</td>
</tr>
</c:forEach>
</table>
</body>
</html>13.9. 下载
13.9.1. 展示列表
13.9.1.1. 控制的方法
java
/**
* 列表展示文件
* 1 xxx 2020年4月1日08:43:35 96530565d35746b19bf5a5ee3251fdf8.txt a.txt
* 2 xxx 2020年4月1日08:43:35 86530565d35746b19bf5a5ee3251fdf8.txt a.txt
* 3 xxx 2020年4月1日08:43:35 76530565d35746b19bf5a5ee3251fdf8.txt b.txt
* 4 xxx 2020年4月1日08:43:35 66530565d35746b19bf5a5ee3251fdf8.txt ctxt
* 5 xxx 2020年4月1日08:43:35 596c08719709471697d0c39df87f8d6f.txt d.txt
* @param 从Controller开始 http://127.0.0.1:8080/springmvc/filelist
*/
@RequestMapping(value = "/filelist")
public String upload(Model model) throws IOException {
//查询数据库 返回list （文件）
//暂时直接列表 D:\java1upload
File uploadDir = new File(BASE_DIR);
//所有文件的数组
File[] files = uploadDir.listFiles();
model.addAttribute("files",files);//将集合放到作用域中。
return "/file/file_list.jsp";
}13.9.1.2. Jsp列表
13.9.2. 提供下载的方法
根据文件名、id等条件查询对象的文件句柄并提供下载功能
13.9.2.1. 编码的形式自己读取文件并通过response响应
java
/**
* http://127.0.0.1:8080/springmvc/download?filename=596c08719709471697d0c39df87f8d6f.txt
* @param filename
* @return
* @throws IOException
*/
@RequestMapping(value = "/download")
public void download(String filename, HttpServletResponse response) throws IOException {
// new File("D:\\java1upload\\",filename);
File downFile = new File(BASE_DIR, filename);
//告诉浏览器下面向浏览器发送附件
response.setHeader("Content-Disposition","attachment;filename="+filename);
ServletOutputStream os = response.getOutputStream();
FileInputStream fis = new FileInputStream(downFile);
int len = 0;
byte[] buffer = new byte[1024];//缓存区
while( (len = fis.read(buffer)) != -1){
os.write(buffer,0,len);
os.flush();
}
os.close();
fis.close();
}Spring-web模块的ResponseEntity类快速的构建一个响应内容
java
/**
* http://127.0.0.1:8080/springmvc/download2?filename=596c08719709471697d0c39df87f8d6f.txt
* @param filename
* @param response
* @return
* @throws IOException
*/
@RequestMapping(value = "/download2")
public ResponseEntity download2(String filename, HttpServletResponse response) throws IOException {
File downFile = new File(BASE_DIR, filename);
ResponseEntity entity = ResponseEntity.ok().
//mime
header(HttpHeaders.CONTENT_TYPE,"application/octet-stream").
//通知浏览器以什么方式处理响应结果（直接打开，附件下载）
header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=\"" + downFile.getName() + "\"").
//设置body中为文件资源
body(new FileSystemResource(downFile));
return entity;
}