Instances of uploaded files in Spring MVC
- 2021-06-28 13:39:12
- OfStack
SpringMVC upload file should pay attention to several points:
1. enctype="multipart/form-data" for form, which is required for uploading files
2. applicationContext.xml Configuration:
<!-- SpringMVC When uploading files, you need to configure MultipartResolver processor -->
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
<property name="defaultEncoding" value="UTF-8"/>
<!-- Specifies that the total size of the uploaded file cannot exceed 200KB .Be careful maxUploadSize Attribute restrictions are not for a single file, but the sum of all file sizes -->
<property name="maxUploadSize" value="200000"/>
<!-- Maximum memory size (10240)-->
<property name="maxInMemorySize" value="40960" />
</bean>
<!-- SpringMVC When the upload file limit is exceeded, it will be thrown org.springframework.web.multipart.MaxUploadSizeExceededException -->
<!-- The exception is SpringMVC Thrown while checking for uploaded file information and has not yet entered Controller Method -->
<bean id="exceptionResolver" class="org.springframework.web.servlet.handler.SimpleMappingExceptionResolver">
<property name="exceptionMappings">
<props>
<!-- encounter MaxUploadSizeExceededException Automatically jump to when an exception occurs /WEB-INF/jsp/error_fileupload.jsp page -->
<prop key="org.springframework.web.multipart.MaxUploadSizeExceededException">error_fileupload</prop>
</props>
</property>
</bean>
Form page for upload/WEB-INF/jsp/upload.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<script type="text/javascript" src="../js/jquery-1.7.1.min.js"></script>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title> Upload pictures </title>
</head>
<body>
<form action="<%=request.getContextPath()%>/upload/filesUpload" method="POST" enctype="multipart/form-data">
yourfile: <input type="file" name="myfiles"/><br/>
yourfile: <input type="file" name="myfiles"/><br/>
<input type="submit" value=" Upload pictures "/>
</form>
</body>
</html>
Prompt page for uploading files with too large contents/WEB-INF/jsp/error_fileupload.jsp
<%@ page language="java" pageEncoding="UTF-8"%>
<h1> File too large, please select again </h1>
Core UploadController class for uploading files
package com.ljq.web.controller.annotation;
import java.io.File;
import javax.servlet.http.HttpServletRequest;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.multipart.MultipartFile;
/**
* Upload pictures
*
* @author Administrator
*
*/
@Controller
@RequestMapping("/upload")
public class UploadController {
@RequestMapping("/toUpload")
public String toUpload() {
return "/upload";
}
/***
* Save File
*
* @param file
* @return
*/
private boolean saveFile(HttpServletRequest request, MultipartFile file) {
// Determine if the file is empty
if (!file.isEmpty()) {
try {
// Saved file path ( If you are using Tomcat Server, files will be uploaded to \\%TOMCAT_HOME%\\webapps\\YourWebProject\\upload\\ In folder )
String filePath = request.getSession().getServletContext()
.getRealPath("/") + "upload/" + file.getOriginalFilename();
File saveDir = new File(filePath);
if (!saveDir.getParentFile().exists())
saveDir.getParentFile().mkdirs();
// Dump File
file.transferTo(saveDir);
return true;
} catch (Exception e) {
e.printStackTrace();
}
}
return false;
}
/**
* Upload pictures
*
* @param files
* @param request
* @return
*/
@RequestMapping("/filesUpload")
public String filesUpload(@RequestParam("myfiles") MultipartFile[] files,
HttpServletRequest request) {
if (files != null && files.length > 0) {
for (int i = 0; i < files.length; i++) {
MultipartFile file = files[i];
// Save File
saveFile(request, file);
}
}
// redirect
return "redirect:/upload/toUpload";
}
}
The file upload development is over.
Some of the methods commonly used in the MultipartFile class:
String getContentType() //Get file MIME type
InputStream getInputStream()//Return file stream
String getName () //Get the name of the file component in the form
String getOriginalFilename()//Get the original name of the uploaded file
long getSize ()//Get the byte size of the file in byte
boolean isEmpty () //Is it empty
void transferTo (File dest)//Save to a target file