Spring Boot学习随笔- 文件上传和下载（在线打卡、附件下载、MultipartFile - ToB企服应用市场:ToB评测及商务社交产业平台

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8" %>
<!DOCTYPE html>
<html>
<head>
<title>文件上传</title>
</head>
<body>
<h1>测试文件上传</h1>
<form action="${pageContext.request.contextPath}/file/upload" method="post" enctype="multipart/form-data">
<input type="file" name="file">
<input type="submit" value="上传文件">
</form>
</body>
</html>

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@Controller
@RequestMapping("file")
public class FileController {
private final Logger log = LoggerFactory.getLogger(FileController.class);
/**
* 测试文件上传
*/
@RequestMapping("upload")
public String upload(MultipartFile file, HttpServletRequest request) throws IOException { // 变量名要和form的input type="file"的name名一致
log.debug("文件名：{}", file.getOriginalFilename());
log.debug("文件大小：{}", file.getSize());
log.debug("文件类型：{}", file.getContentType());
// 处理文件上传根据相对路径上传 upload 获取绝对路径(真实路径) /users/desktop
String realpath = request.getSession().getServletContext().getRealPath("/upload");
log.debug("获取绝对路径：{}", realpath);
// 修改文件名
String fileName = file.getOriginalFilename();
int i = fileName.lastIndexOf(".");
String suffix = fileName.substring(i);
String newFileName = new SimpleDateFormat("yyyyMMddHHmmssSSS").format(new Date())+suffix;
// 上传文件参数1将文件写进目录
file.transferTo(new File(realpath,newFileName));
return "redirect:/upload.jsp";
}
}

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@Value("${file.upload.dir}")
private String **realPath**;
/**
* 【推荐】适用于任何一种部署方式
* @param file
* @return
* @throws IOException
*/
@RequestMapping("uploadByJarDeploy")
public String uploadByJarDeploy(MultipartFile file) throws IOException {
log.debug("文件名：{}", file.getOriginalFilename());
log.debug("文件大小：{}", file.getSize());
log.debug("文件类型：{}", file.getContentType());
// 修改文件名
String fileName = file.getOriginalFilename();
int i = fileName.lastIndexOf(".");
String suffix = fileName.substring(i);
String newFileName = new SimpleDateFormat("yyyyMMddHHmmssSSS").format(new Date()) + suffix;
// 文件上传
file.transferTo(new File(**realPath**,newFileName));
return "redirect:/upload.jsp";
}

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@Controller
@RequestMapping("file")
public class FileController {
private Logger log = LoggerFactory.getLogger(FileController.class);
@Value("${file.download.dir}")
private String realPath;
/**
* 文件下载
* @param fileName
*/
@RequestMapping("download")
public void download(StringopenStyle, String fileName, HttpServletResponse response) throws IOException {
openStyle=openStyle==null?"inline":"attachment";
log.debug("当前下载文件名：{}", fileName);
log.debug("当前下载目录：{}", realPath);
// 1.指定目录中读取文件
File file = new File(realPath, fileName);
// 2.将文件读取为文件输入流
FileInputStream is = new FileInputStream(file);
// 3.获取响应输出流
response.setContentType("text/plain;charset=UTF-8");
ServletOutputStream os = response.getOutputStream();
// 4.附件下载文件 attachment(附件) inline(在线打开)
response.setHeader("content-disposition",openStyle+";fileName=" + URLEncoder.encode(fileName,"UTF-8"));
// 5.输入流复制给输出流
// 传统写法
// int len = 0;
// byte[] b = new byte[1024];
// while (true) {
// len = is.read(b);
// if (len == -1) {
// break;
// }
// os.write(b, 0, len);
// }
// is.close();
// spring提供的复制方法，会自动释放is和os
FileCopyUtils.copy(is, os);
}
}

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<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8" %>
<!DOCTYPE html>
<html>
<head>
<title>下载</title>
</head>
<body>
<h1>文件下载</h1>
<ul>
<li>
help.md
<a target="_blank" href="https://www.cnblogs.com/${pageContext.request.contextPath}/file/download?fileName=HELP.md">在线打开</a>
<a target="_blank" href="https://www.cnblogs.com/${pageContext.request.contextPath}/file/download?fileName=HELP.md&openStyle=attachment">附件下载</a>
</li>
<li>
springmvc.png
<a target="_blank" href="https://www.cnblogs.com/${pageContext.request.contextPath}/file/download?fileName=20231219161718427.png">在线打开</a>
<a target="_blank" href="https://www.cnblogs.com/${pageContext.request.contextPath}/file/download?fileName=20231219161718427.png&openStyle=attachment">附件下载</a>
</li>
</ul>
</body>
</html>

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