使用Apache发布的Commons FileUpload
- Servlet 3.0规范已经提供方法来处理文件上传,但是这种上传需要在Servlet中完成
- Spring MVC提供了更简单的封装, 使用即插即用的
MultipartResolver实现 - Spring MVC使用Apache发布的Commons FileUpload技术实现
MultipartResolver类:CommonsMultipartResolver,所以SpringMVC的文件上传依赖Apache的Commons FileUpload
导入jar包: commons-fileupload,以及高版本的servlet
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10<dependency>
<groupId>commons-fileupload</groupId>
<artifactId>commons-fileupload</artifactId>
<version>1.4</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>4.0.1</version>
</dependency>配置bean: multipartResolver
注意这个bean的id必须为multipartResolver,否则上传文件会报400的错误
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8<!--文件上传配置-->
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
<!--请求的编码格式,必须和jsp的pageEncoding一直,以便正确读取表单内容,默认IOS-8859-1-->
<property name="defaultEncoding" value="utf-8"/>
<!--上传文件大小上限,这里是10M-->
<property name="maxUploadSize" value="10485760"/>
<property name="maxInMemorySize" value="40960"/>
</bean>写一个简单的页面测试
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12<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>$Title$</title>
</head>
<body>
<form action="${pageContext.request.contextPath}/upload" enctype="multipart/form-data" method="post">
<input type="file" name="file"/>
<input type="submit" value="upload">
</form>
</body>
</html>Controller
上传
两种方法
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86package zone.yiqing.controller;
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.*;
/**
* @Author Yiqing Zhang
* @Date 2020-11-17 3:51 p.m.
* @Version 1.0
*/
public class FileController {
/**
* InputStream OutputSteaam
* @param file
* @param request
* @return
* @throws IOException
*/
public String upload(CommonsMultipartFile file, HttpServletRequest request) throws IOException {
// 获取文件名
String originalFilename = file.getOriginalFilename();
// 文件名为空,返回首页
if("".equals(originalFilename)){
return "redirect:/index.jsp";
}
System.out.println("上传文件名: " + originalFilename);
// 上传路径保存设置(可以使用UUID)
String path = request.getServletContext().getRealPath("/upload");
// 如果路径不存在,创建
File realPath = new File(path);
if(!realPath.exists()){
realPath.mkdir();
}
System.out.println("文件上传保存地址: " + realPath);
InputStream inputStream = file.getInputStream();// 文件输入流
OutputStream outputStream = new FileOutputStream(new File(realPath, originalFilename));// 文件输出流
// 读取写出
int len = 0;
byte[] buffer = new byte[1024];
while ((len=inputStream.read(buffer))!=-1){
outputStream.write(buffer,0,len);
outputStream.flush();
}
outputStream.close();
inputStream.close();
return "redirect:/index.jsp";
}
/**
* 采用file.Transto 来保存
* @param file
* @param request
* @return
* @throws IOException
*/
public String upload2(CommonsMultipartFile file, HttpServletRequest request) throws IOException{
// 上传路径保存设置
String path = request.getServletContext().getRealPath("/upload");
// 如果路径不存在,创建
File realPath = new File(path);
if(!realPath.exists()){
realPath.mkdir();
}
System.out.println("文件上传保存地址: " + realPath);
// 通过CommonsMultipartFile的方法直接写文件
file.transferTo(new File(realPath + "/" + file.getOriginalFilename()));;
return "redirect:/index.jsp";
}
}下载
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public String download(HttpServletResponse response, HttpServletRequest request) throws Exception{
// 要下载的地址
String path = request.getServletContext().getRealPath("/upload");
String fileName = "xxx.jpg";
// 1. 设置response响应头
response.reset(); // 设置页面不缓存,清空buffer
response.setContentType("multipart/form-data"); // 二进制传输数据
response.setHeader("Content-Disposition","attachment;fileName="+ URLEncoder.encode(fileName,"UTF-8"));
File file = new File(path,fileName);
// 2. 读取文件---输入流
InputStream inputStream = new FileInputStream(file);
// 3. 写入文件---输出流
OutputStream outputStream = response.getOutputStream();
byte[] buffer = new byte[1024];
int index = 0;
while ((index=inputStream.read(buffer)) != -1){
outputStream.write(buffer,0,index);
outputStream.flush();
}
outputStream.close();
inputStream.close();
return null;
}
