How to use SpringBoot framework to receive multipart/form-data files
SpringBoot框架接收multipart/form-data文件
现在很多文件上传类型都是multipart/form-data类型的，HTTP请求如下所示：
可是问题就在于如果用传统的Struts2或者servlet等都可以很容易的实现文件接收的功能，例如下面的代码就可以实现：
boolean isMultipart = ServletFileUpload.isMultipartContent(request);//判断是否是表单文件类型
DiskFileItemFactory factory = new DiskFileItemFactory();
ServletFileUpload sfu = new ServletFileUpload(factory);
List items = sfu.parseRequest(request);//从request得到所有上传域的列表
for(Iterator iter = items.iterator();iter.hasNext();){
FileItem fileitem =(FileItem) iter.next();
if(!fileitem.isFormField()&&fileitem!=null){//判读不是普通表单域即是file
System.out.println("name:"+fileitem.getName());
}
}可是今天我把这一段代码放在SpringBoot上面的时候就怎么也接收不到文件信息了，一直以为是前端什么数据传输错了。后来才知道原来SpringBoot有它自己的接收请求的代码。下面就给大家详细介绍一下它是如何实现这个功能的。
首选做一个简单的案例，也就是单个文件上传的案例。为了进行这个案例，首先需要建立一个SpringBoot框架
前台HTML代码：
<html>
<body>
<form action="/upload" method="POST" enctype="multipart/form-data">
<input type="file" name="file"/>
<input type="submit" value="Upload"/>
</form>
</body>
</html>
后台接收代码：
/**
* 文件上传具体实现方法;
*
* @param file
* @return
*/
@RequestMapping("/upload")
@ResponseBody
public String handleFileUpload(@RequestParam("file") MultipartFile file) {
if (!file.isEmpty()) {
try {
/*
* 这段代码执行完毕之后，图片上传到了工程的跟路径； 大家自己扩散下思维，如果我们想把图片上传到
* d:/files大家是否能实现呢？ 等等;
* 这里只是简单一个例子,请自行参考，融入到实际中可能需要大家自己做一些思考，比如： 1、文件路径； 2、文件名；
* 3、文件格式; 4、文件大小的限制;
*/
BufferedOutputStream out = new BufferedOutputStream(
new FileOutputStream(new File(
file.getOriginalFilename())));
System.out.println(file.getName());
out.write(file.getBytes());
out.flush();
out.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
return "上传失败," + e.getMessage();
} catch (IOException e) {
e.printStackTrace();
return "上传失败," + e.getMessage();
}
return "上传成功";
} else {
return "上传失败，因为文件是空的.";
}
}这样便可以接收multipart/form-data类型的文件。接下来，我们来看一个上传多个文件并且每个文件都有多个字段的案例。
前台HTML界面：
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" xmlns:th="http://www.thymeleaf.org"
xmlns:sec="http://www.thymeleaf.org/thymeleaf-extras-springsecurity3">
<head>
<title>Hello World!</title>
</head>
<body>
<form method="POST" enctype="multipart/form-data" action="/batch/upload">
<p>文件1：<input type="text" name="id" /></p>
<p>文件2：<input type="text" name="name" /></p>
<p>文件3：<input type="file" name="file" /></p>
<p><input type="submit" value="上传" /></p>
</form>
</body>
</html>
后台接收代码：
@RequestMapping(value = "/batch/upload", method = RequestMethod.POST)
@ResponseBody
public String handleFileUpload(HttpServletRequest request) {
MultipartHttpServletRequest params=((MultipartHttpServletRequest) request);
List<MultipartFile> files = ((MultipartHttpServletRequest) request)
.getFiles("file");
String name=params.getParameter("name");
System.out.println("name:"+name);
String id=params.getParameter("id");
System.out.println("id:"+id);
MultipartFile file = null;
BufferedOutputStream stream = null;
for (int i = 0; i < files.size(); ++i) {
file = files.get(i);
if (!file.isEmpty()) {
try {
byte[] bytes = file.getBytes();
stream = new BufferedOutputStream(new FileOutputStream(
new File(file.getOriginalFilename())));
stream.write(bytes);
stream.close();
} catch (Exception e) {
stream = null;
return "You failed to upload " + i + " => "
+ e.getMessage();
}
} else {
return "You failed to upload " + i
+ " because the file was empty.";
}
}
return "upload successful";
}这样就可以实现对多个文件的接收了功能了。
SpringBoot还可以对接收文件的格式还有个数等等进行限制，我这里就不多说了，大家有兴趣的可以自己去了解了解。
千万要记住SpringBoot对multipart/form-data类型的文件接收和其它是不一样的，大家以后遇到的时候要千万小心，不要像我一样一往无前的踩进去还傻傻的以为是前端的错误。
SpringBoot接收文件
package cn.juhe.controller;
import net.sf.json.JSONObject;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.multipart.MultipartHttpServletRequest;
import javax.servlet.http.HttpServletRequest;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Date;
import java.util.Iterator;
import java.util.List;
import java.util.Random;
@RestController
public class UploadTest {
/**
* 接受未知参数名的多个文件或者一个文件
*
* @param request 请求
* @return 返回
*/
@PostMapping("/upload")
public JSONObject handleFileUpload(HttpServletRequest request) {
Iterator<String> fileNames = ((MultipartHttpServletRequest) request).getFileNames();
JSONObject result = null;
while (fileNames.hasNext()) {
String next = fileNames.next();
MultipartFile file = ((MultipartHttpServletRequest) request).getFile(next);
System.out.println("file.getName():" + file.getName());
System.out.println("file.getOriginalFilename():" + file.getOriginalFilename());
String folder = "E:\\upload\\received\\";
String picName = new Date().getTime() + ".jpg";
File filelocal = new File(folder, picName);
result = new JSONObject();
result.put(picName, folder + picName);
try {
file.transferTo(filelocal);
} catch (IOException e) {
e.printStackTrace();
}
}
JSONObject jsonObject = new JSONObject();
jsonObject.put("error_code", 223805);
jsonObject.put("reason", "文件过大或上传发生错误");
Random random = new Random();
if (random.nextInt(10) > 3) {
jsonObject.put("error_code", 0);
jsonObject.put("reason", "success");
jsonObject.put("result", result);
}
return jsonObject;
}
/**
* 知道参数名的文件上传
*
* @param multipartFile 文件
* @return 返回
* @throws IOException
*/
@PostMapping("/uploadCommon")
//public JSONObject upload(MultipartFile multipartFile) throws IOException {
public JSONObject upload(@RequestParam("A") MultipartFile multipartFile) throws IOException {
String name = multipartFile.getName();//上传文件的参数名
String originalFilename = multipartFile.getOriginalFilename();//上传文件的文件路径名
long size = multipartFile.getSize();//文件大小
String folder = "E:\\upload\\received\\";
String picName = new Date().getTime() + ".jpg";
File filelocal = new File(folder, picName);
multipartFile.transferTo(filelocal);
/* {
"reason": "success",
"result": {
"D": "/upload/order/files/2016/a72750ad-8950-4949-b04a-37e69aff0d23.jpg",
"A": "/upload/order/files/2016/6842811a-eb76-453b-a2f3-488e2bb4500e.jpg",
"B": "/upload/order/files/2016/ccc96347-3cb8-4e2e-99a3-0c697b57eb88.jpg",
"C": "/upload/order/files/2016/d470d533-a54b-406a-a0f9-bbf82c314755.jpg"
},
"error_code": 0
}*/
JSONObject jsonObject = new JSONObject();
jsonObject.put("error_code", 223805);
jsonObject.put("reason", "文件过大或上传发生错误");
Random random = new Random();
if (random.nextInt(10) > 3) {
jsonObject.put("error_code", 0);
jsonObject.put("reason", "success");
JSONObject result = new JSONObject();
result.put(name, folder + picName);
jsonObject.put("result", result);
}
return jsonObject;
}
}The above is the detailed content of How to use SpringBoot framework to receive multipart/form-data files. For more information, please follow other related articles on the PHP Chinese website!
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