This is a very simple demo that can upload files on the front end and then receive and process them on the back end. Finally, you can pass a file to the front end for download.
front end
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<style type="text/css">
.divForm {
position: absolute; /*绝对定位*/
width: 300px;
height: 200px;
border: 1px solid #595fff;
text-align: center; /*(让div中的内容居中)*/
top: 50%;
left: 50%;
margin-top: -200px;
margin-left: -150px;
}
</style>
</head>
<body>
<div class="divForm">
<form id="upload-form" action="/book-converter" method="post" enctype="multipart/form-data">
<input type="file" id="upload" name="upload"/> <br/>
<input type="submit" value="Upload"/>
</form>
</div>
</body>
<script>
form.on('submit', function () {
// 此处进行ajax上传
// 检查是否支持FormData
if (window.FormData) {
var formData = new FormData();
// 建立一个upload表单项，值为上传的文件
formData.append('upload', document.getElementById('upload').files[0]);
var xhr = new XMLHttpRequest();
xhr.open('POST', $(this).attr('action'));
// 定义上传完成后的回调函数
xhr.onload = function () {
if (xhr.status === 200) {
console.log('上传成功');
} else {
console.log('出错了');
}
};
xhr.send(formData);
}
});
</script>
</html>
rear end
- Receive files
- Processing files: Convert MultipartFile into File in Java, read directly from MultipartFile line by line, and then write to File
- Send a file directly to the front end for downloading
package com.amwalle.walle.controller;
import com.amwalle.walle.util.PDFConverter;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.util.MultiValueMap;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.multipart.support.StandardMultipartHttpServletRequest;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.net.URLEncoder;
import java.nio.charset.StandardCharsets;
import java.util.Objects;
import java.util.Scanner;
@RestController
public class BookConverterController {
private static final Logger logger = LoggerFactory.getLogger(BookConverterController.class);
@RequestMapping(value = "/book-converter", method = RequestMethod.POST)
public void handleUpload(HttpServletRequest request, HttpServletResponse response) throws IOException {
MultiValueMap<String, MultipartFile> multiFileMap = ((StandardMultipartHttpServletRequest) request).getMultiFileMap();
MultipartFile multipartFile = multiFileMap.getFirst("upload");
assert multipartFile != null;
File resource = new File(Objects.requireNonNull(multipartFile.getOriginalFilename()));
logger.info("处理的文件： " + multipartFile.getOriginalFilename());
try (BufferedReader reader = new BufferedReader(new InputStreamReader(multipartFile.getInputStream(), StandardCharsets.UTF_8))) {
BufferedWriter outWriter = new BufferedWriter(new FileWriter(resource));
String line = reader.readLine();
while (line != null) {
outWriter.write(line);
outWriter.write("\n");
line = reader.readLine();
}
outWriter.flush();
}
String fileName = multipartFile.getOriginalFilename();
assert fileName != null;
fileName = fileName.substring(0, fileName.lastIndexOf("."));
String outputFileName = URLEncoder.encode(fileName + "1" + ".html", "UTF-8");
response.setContentType("application/x-download");
response.setCharacterEncoding("UTF-8");
response.addHeader("Content-Disposition", "attachment;filename=" + outputFileName);
ServletOutputStream out = response.getOutputStream();
OutputStreamWriter writer = new OutputStreamWriter(out, StandardCharsets.UTF_8);
if (!multipartFile.getOriginalFilename().endsWith(".html")) {
logger.info("文件不是HTML格式！");
writer.write("请上传HTML文件");
writer.flush();
return;
}
File outFile = PDFConverter.convert(resource);
try (Scanner scanner = new Scanner(outFile, "UTF-8");) {
while (scanner.hasNextLine()) {
writer.write(scanner.nextLine());
writer.write("\n");
}
} catch (Exception e) {
logger.info("处理出错");
writer.write("处理出错了！");
writer.write(e.getMessage());
writer.flush();
outFile.deleteOnExit();
return;
}
writer.flush();
outFile.deleteOnExit();
logger.info("文件处理成功！");
}
}