)
public String fileUpload(@RequestParam(value = "file") MultipartFile multipartFile,
HttpServletRequest request, String introduce)
throws IOException {
//接收到提交的文件名
String originalFilename = multipartFile.getOriginalFilename();
System.out.println("你上传的文件介绍=" + introduce);
System.out.println("你上传的文件名=" + originalFilename);
//得到上传的文件要保存的路径[全路径：包括文件名]
//这里其实是out目录下的路径
String fileFullPath =
request.getServletContext().getRealPath("/img/" + originalFilename);
//创建文件
File saveToFile = new File(fileFullPath);
//将上传文件转存到 saveToFile
multipartFile.transferTo(saveToFile);
return "success";
}
}
（7）启动 tomcat，访问 fileUpload.jsp，选择文件上传
后台输出：
上传的文件：
这里只是模拟，真正开发中不会将文件存放在项目目录中，而是存放在主机的另外的磁盘上，每次存放文件时会将存放路径保存到数据库中。下载文件时会读取数据库数据，得到路径，寻找文件。
postman 也可以进行文件上传：
3.transferTO()方法
@Override
public void transferTo(File dest) throws IOException, IllegalStateException {
//首先判断该文件(路径)在磁盘中是不是可获取的
if (!isAvailable()) {
throw new IllegalStateException("File has already been moved - cannot be transferred again");
}
//判断上传的文件在磁盘中存不存在，如果存在就会去尝试删除该文件，如果删除失败，就会抛出异常
if (dest.exists() && !dest.delete()) {
throw new IOException(
"Destination file [" + dest.getAbsolutePath() + "] already exists and could not be deleted");
}
//如果文件不存在，或者存在但删除成功了
try {
//将上传的文件拷贝到目标目录 dest 下
//this.fileItem 就是你要上传文件的临时文件（tmp文件）
//就是说 SpringMVC 上传文件也是先将上传文件保存为临时文件，然后再拷贝为目标文件
this.fileItem.write(dest);
LogFormatUtils.traceDebug(logger, traceOn -> {
String action = "transferred";
if (!this.fileItem.isInMemory()) {
action = (isAvailable() ? "copied" : "moved");
}
return "Part '" + getName() + "', filename '" + getOriginalFilename() + "'" +
(traceOn ? ", stored " + getStorageDescription() : "") +
": " + action + " to [" + dest.getAbsolutePath() + "]";
});
}
catch (FileUploadException ex) {
throw new IllegalStateException(ex.getMessage(), ex);
}
catch (IllegalStateException | IOException ex) {
// Pass through IllegalStateException when coming from FileItem directly,
// or propagate an exception from I/O operations within FileItem.write
throw ex;
}
catch (Exception ex) {
throw new IOException("File transfer failed", ex);
}
}