上传同一张图片的结果如图所示：
?希望所有的coders写的代码都能向这张图一样0 Errors, 0 Warnings~~~
?
1. 首先在pom.xml和springMVC.xml这两个XML文件中进行配置；
1.1 在pom.xml中配置文件上传解析器commons-fileupload，配置代码如下：
<!--配置文件上传解析器-->
<dependency>
<groupId>commons-fileupload</groupId>
<artifactId>commons-fileupload</artifactId>
<version>1.3.1</version>
</dependency>1.2 在springMVC.xml中配置文件上传解析器，并将上传的文件封装为MultipartFile：
<!--配置文件上传解析器，将上传的文件封装为MultipartFile-->
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver"></bean>2. 简单编写一个实现文件上传和下载的HTML页面：
<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
<meta charset="UTF-8">
<title>测试文件上传和下载</title>
</head>
<body>
<a th:href="@{/testDown}">下载1.jpg</a><br>
<form th:action="@{/testUp}" method="post" enctype="multipart/form-data">
头像:<input type="file" name="photo"><br>
<input type="submit" value="上传">
</form>
</body>
</html>3. 用SpringMVC实现文件上传和下载的控制器FileUpAndDownController，代码如下：
package com.study.mvc.controller;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.util.MultiValueMap;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.multipart.MultipartFile;
import javax.servlet.ServletContext;
import javax.servlet.http.HttpSession;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.UUID;
@Controller
public class FileUpAndDownController {
@RequestMapping("/testDown")
public ResponseEntity<byte[]> testResponseEntity(HttpSession session) throws IOException{
//获取servletContext对象
ServletContext servletContext = session.getServletContext();
//获取服务器中文件的真实路径
String realPath = servletContext.getRealPath("/static/img/1.jpg");
System.out.println(realPath);
//创建输入流
FileInputStream is = new FileInputStream(realPath);
//创建字节数组
byte[] bytes = new byte[is.available()];
//将流读到字节数组中
is.read(bytes);
//创建HttpHeaders对象设置响应头信息
MultiValueMap<String,String> headers = new HttpHeaders();
//设置下载方式以及下载文件的名字
headers.add("Content-Disposition", "attachment;filename=1.jpg");
//设置响应状态码
HttpStatus statusCode = HttpStatus.OK;
//创建ResponseEntity对象
ResponseEntity<byte[]> responseEntity = new ResponseEntity<>(bytes, headers, statusCode);
//关闭输入流
is.close();
return responseEntity;
}
@RequestMapping("/testUp")
public String testUp(MultipartFile photo, HttpSession session) throws IOException {
//获取上传文件的文件名
String fileName = photo.getOriginalFilename();
//获取上传的文件后缀名
String suffix = fileName.substring(fileName.lastIndexOf("."));
//将UUID作为文件名
String uuid = UUID.randomUUID().toString();
//将uuid和后缀名拼接后的结果作为最终的文件名
fileName = uuid+suffix;
//通过ServletContext获取服务器中photo目录的路径
ServletContext servletContext = session.getServletContext();
String photoPath = servletContext.getRealPath("photo");
File file = new File(photoPath);
if (!file.exists()){
file.mkdir(); //若路径不存在，则创建目录
}
String finalPath = photoPath+File.separator+fileName;
photo.transferTo(new File(finalPath));
return "success";
}
}
