java web 之springmvc教程(八)-----实现文件上传及下载

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我是靠谱客的博主飘逸咖啡豆，最近开发中收集的这篇文章主要介绍java web 之springmvc教程(八)-----实现文件上传及下载，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

导入包：

<!-- https://mvnrepository.com/artifact/commons-fileupload/commons-fileupload -->
<dependency>
<groupId>commons-fileupload</groupId>
<artifactId>commons-fileupload</artifactId>
<version>1.3.3</version>
</dependency>

单个文件的上传

前台页面index.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/fmt" prefix="fmt"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<body>
<h2>Hello World!</h2>
<body>
<form action="${pageContext.request.contextPath }/doupload.action" method="post" enctype="multipart/form-data">
<h2>文件上传</h2>
文件:<input type="file" name="uploadFile"/><br/><br/>
<input type="submit" value="上传"/>
</form>
</body>
</body>
</html>

springmvc.xml中添加:

<!-- 文件上传,需要配置MultipartResolver处理器 -->
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
<!-- 设置船上文件的最大尺寸为5MB -->
<property name="maxUploadSize" value="5242880"/>
<property name="defaultEncoding" value="utf-8"/>
</bean>

controller添加：

@RequestMapping("/doupload")
public String doupload(MultipartFile uploadFile,HttpSession session) throws Exception{
String filename = uploadFile.getOriginalFilename();
String leftPath= session.getServletContext().getRealPath("/images");
System.out.println("leftpath======" + leftPath);
File file = new File(leftPath,filename);
uploadFile.transferTo(file);
return "/WEB-INF/jsp/success.jsp";
}

先建立images文件夹。

springmvc文件上传的类是MultipartFile。uploadFile必须与jsp中的name一致。

多个文件的上传

index.jsp:

<form action="${pageContext.request.contextPath }/doupload2.action" method="post" enctype="multipart/form-data">
<h2>文件上传</h2>
文件:<input type="file" name="uploadFile2"/><br/>
<input type="file" name="uploadFile2"/><br/>
<input type="file" name="uploadFile2"/><br/><br/>
<input type="submit" value="上传2"/>
</form>

controller:

@RequestMapping("/doupload2")
public String doupload(@RequestParam MultipartFile[] uploadFile2,HttpSession session) throws Exception{
for(MultipartFile item :uploadFile2){
if(item.getSize()>0){
String filename = item.getOriginalFilename();
String leftPath= session.getServletContext().getRealPath("/images");
File file = new File(leftPath,filename);
item.transferTo(file);
}else{
return "/WEB-INF/jsp/error.jsp";
}
}
return "/WEB-INF/jsp/success.jsp";
}

测试成功。

文件下载

index.jsp

<a href="${pageContext.request.contextPath }/download.action?line.jpg">下载</a>

controller:

 @RequestMapping("/download")
public ResponseEntity<byte[]> download() throws IOException {
File file = new File("D:\line.jpg");
HttpHeaders headers = new HttpHeaders();
String filename = new String("hello.jpg".getBytes("utf-8"),"iso-8859-1");
headers.setContentDispositionFormData("attachment",filename);
headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
return new ResponseEntity<byte[]>(FileUtils.readFileToByteArray(file),headers, HttpStatus.CREATED);
}

测试成功！