1：首先搭建了一个sprigmvc的环境，在spring的配置文件中添加下面的配置。里面还可以有很多其他的参数。
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
<!-- 设置上传文件的最大尺寸为5MB -->
<property name="maxUploadSize" value="5242880"/>
<property name="defaultEncoding" value="utf-8"/>
</bean>
前台表单页面
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Title</title>
</head>
<body>
<form enctype="multipart/form-data" action="${pageContext.request.contextPath}/upload" method="post">
<input type="file" name="file">
<input type="submit" value="upload">
</form>
<hr>
<form enctype="multipart/form-data" action="${pageContext.request.contextPath}/upload2" method="post">
<input type="file" name="file">
<input type="submit" value="upload">
</form>
</body>
</html>
controller层
package com.dongmu.controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.commons.CommonsMultipartFile;
import javax.servlet.http.HttpServletRequest;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.UUID;
@RestController
public class MyController {
@RequestMapping("/upload")
public String upload(@RequestParam("file") CommonsMultipartFile file, HttpServletRequest request) throws IOException {
String name = file.getOriginalFilename();
//注意：String getFieldName()：获取表单项的name的属性值。
// System.out.println("上传文件的全部路径："+name);
//获取上传文件的文件名
if (name!=null&&name.length()>0){
// String uuidPath= UUID.randomUUID().toString();
String uploadPath = request.getServletContext().getRealPath("/upload");
/*File uploadFile = new File(uploadPath);
if (!uploadFile.exists()){
uploadFile.mkdir();
}*/
// String realPath = uploadPath+"/"+uuidPath;
File realuploadFile = new File(uploadPath);
if (!realuploadFile.exists()){
realuploadFile.mkdirs();
}
//获得文件的上传流
InputStream inputStream = file.getInputStream();
//获取文件的输出流
FileOutputStream outputStream = new FileOutputStream(new File(realuploadFile,name));
//创建一个缓冲区
byte[] bytes = new byte[1024*1024];
int len = 0;
while ((len=inputStream.read(bytes))>0){
outputStream.write(bytes,0,len);
}
outputStream.close();
inputStream.close();
System.out.println("文件上传成功");
return "redirect:/index.jsp";
}else {
return "redirect:/index.jsp";
}
}
@RequestMapping("/upload2")
public String upload2(@RequestParam("file") CommonsMultipartFile file, HttpServletRequest request) throws IOException {
String uploadPath = request.getServletContext().getRealPath("/upload");
File uploadFile = new File(uploadPath);
if (!uploadFile.exists()){
uploadFile.mkdir();
}
file.transferTo(new File(uploadFile+"/"+file.getOriginalFilename()));
return "redirect:/index.jsp";
}
}
springMVC利用response实现资源的下载
@RequestMapping("/download")
public void download2(HttpServletRequest request, HttpServletResponse response) throws IOException {
System.out.println(123);
String realpath = request.getServletContext().getRealPath("/");
String filename = "壁纸.jpg";
System.out.println(realpath);
response.setHeader("Content-Disposition", "attachment;fileName="+ URLEncoder.encode(filename,"utf-8"));
FileInputStream inputStream = new FileInputStream(realpath+"static/nsn.jpg");
response.setContentType("multipart/form-data");
System.out.println(222);
byte[] bytes = new byte[1024];
int len =0;
//用response对象获取输出流
ServletOutputStream outputStream = response.getOutputStream();
while ((len=inputStream.read(bytes))>0){
outputStream.write(bytes,0,len);
}
System.out.println(333);
inputStream.close();
outputStream.close();
}
要保证自己网站下面的资源目录里面有这个资源，不然会出错。