一、文件上传
使用
SpringMVC6
版本,不需要添加以下依赖:
<dependency>
<groupId>commons-fileupload</groupId>
<artifactId>commons-fileupload</artifactId>
<version>1.5</version>
</dependency>
前端页面index.html:
<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
<meta charset="UTF-8">
<title>文件上传</title>
</head>
<body>
<!--文件上传表单-->
<form th:action="@{/file/up}" method="post" enctype="multipart/form-data">
文件:<input type="file" name="fileName"/><br>
<input type="submit" value="上传">
</form>
</body>
</html>
重点是:form表单采用post请求,enctype是multipart/form-data,并且上传组件是:type=“file”
web.xml文件:
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="https://jakarta.ee/xml/ns/jakartaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="https://jakarta.ee/xml/ns/jakartaee https://jakarta.ee/xml/ns/jakartaee/web-app_6_0.xsd"
version="6.0">
<!--前端控制器-->
<servlet>
<servlet-name>springmvc</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<!--通过初始化参数来指定springmvc配置文件的路径和名字。-->
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:springmvc.xml</param-value>
</init-param>
<!--在服务器启动的时候初始化DispatcherServlet,提高第一次访问的效率-->
<load-on-startup>1</load-on-startup>
<multipart-config>
<!--设置单个支持最大文件的大小-->
<max-file-size>102400</max-file-size>
<!--设置整个表单所有文件上传的最大值-->
<max-request-size>102400</max-request-size>
<!--设置最小上传文件大小-->
<file-size-threshold>0</file-size-threshold>
</multipart-config>
</servlet>
<servlet-mapping>
<servlet-name>springmvc</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
<!--隐藏的HTTP请求方式过滤器-->
<filter>
<filter-name>hiddenHttpMethodFilter</filter-name>
<filter-class>org.springframework.web.filter.HiddenHttpMethodFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>hiddenHttpMethodFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
</web-app>
重点:在DispatcherServlet配置时,添加 multipart-config 配置信息。(这是Spring6,如果是Spring5,则不是这样配置,而是在springmvc.xml文件中配置:CommonsMultipartResolver)
SpringMVC6中把这个类已经删除了。废弃了。
Controller中的代码:
package com.liming.controller;
import jakarta.servlet.http.HttpServletRequest;
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.MultipartFile;
import java.io.*;
import java.util.UUID;
@Controller
public class FileController {
@RequestMapping(value = "/file/up", method = RequestMethod.POST)
public String fileUp(@RequestParam("fileName") MultipartFile multipartFile, HttpServletRequest request) throws IOException {
String name = multipartFile.getName();
System.out.println(name);
// 获取文件名
String originalFilename = multipartFile.getOriginalFilename();
System.out.println(originalFilename);
// 将文件存储到服务器中
// 获取输入流
InputStream in = multipartFile.getInputStream();
// 获取上传之后的存放目录
File file = new File(request.getServletContext().getRealPath("/upload"));
// 如果服务器目录不存在则新建
if(!file.exists()){
file.mkdirs();
}
// 开始写
//BufferedOutputStream out = new BufferedOutputStream(new FileOutputStream(file.getAbsolutePath() + "/" + originalFilename));
// 可以采用UUID来生成文件名,防止服务器上传文件时产生覆盖
BufferedOutputStream out = new BufferedOutputStream(new FileOutputStream(file.getAbsolutePath() + "/" + UUID.randomUUID().toString() + originalFilename.substring(originalFilename.lastIndexOf("."))));
byte[] bytes = new byte[1024 * 100];
int readCount = 0;
while((readCount = in.read(bytes)) != -1){
out.write(bytes,0,readCount);
}
// 刷新缓冲流
out.flush();
// 关闭流
in.close();
out.close();
return "ok";
}
}
ok.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>ok</title>
</head>
<body>
<h1>OK!</h1>
</body>
</html>
最终测试结果:
建议:上传文件时,文件起名采用UUID。以防文件覆盖
二、文件下载
<!--文件下载-->
<a th:href="@{/download}">文件下载</a>
文件下载核心程序,使用ResponseEntity:
@GetMapping("/download")
public ResponseEntity<byte[]> downloadFile(HttpServletResponse response, HttpServletRequest request) throws IOException {
File file = new File(request.getServletContext().getRealPath("/upload") + "/1.jpeg");
// 创建响应头对象
HttpHeaders headers = new HttpHeaders();
// 设置响应内容类型
headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
// 设置下载文件的名称
headers.setContentDispositionFormData("attachment", file.getName());
// 下载文件
ResponseEntity<byte[]> entity = new ResponseEntity<byte[]>(Files.readAllBytes(file.toPath()), headers, HttpStatus.OK);
return entity;
}
效果: