我们经常会使用的一个功能是文件下载，既然有文件下载就会有文件上传，下面我们来看一下文件上传是如何实现的
首先准备好一个页面
<style type="text/css"> form{ margin:0px auto; border:1px solid red; width:500px; padding:20px; } </style> </head> <body> <form action="${pageContext.request.contextPath }/frist.do" method="post" enctype="multipart/form-data"> <h1>文件上传</h1> 文件：<input type="file" name="uploadFile"/><br/> 文件：<input type="file" name="uploadFile"/><br/> 文件：<input type="file" name="uploadFile"/><br/> <input type="submit" value="上传"> </form> </body>
单文件上传
通过对文件的大小来判断是否有文件
通过文件的类型来判断是否是允许
@Controller public class MyController { @RequestMapping(value="/frist.do", method=RequestMethod.POST) public String doFirst(HttpSession session,MultipartFile uploadFile)throws Exception{ if(uploadFile.getSize()>0){ //02.获取前半部分路径，jiangWebRoot下一个名称为images文件夹 转换成绝对路径 String path = session.getServletContext().getRealPath("/upload"); //01.获取文件名作为保存到服务器的文件名称 String fileName=uploadFile.getOriginalFilename(); if(fileName.endsWith(".jpg")||fileName.endsWith(".JPG")){ //03.路径拼接 File file = new File(path,fileName); uploadFile.transferTo(file); } return "welcome.jsp"; } return "error.jsp"; }
applicationContext.xml配置
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:mvc="http://www.springframework.org/schema/mvc" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd "> <!-- 配置包扫描器 --> <context:component-scan base-package="cn.controller"></context:component-scan> <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver"> <property name="defaultEncoding" value="utf-8"></property><!-- 客户端发送数据的编码 --> <property name="maxUploadSize" value="5242880"></property><!-- 上传文件的大小 --> <!-- <property name="uploadTempDir" value="/upload"></property> --> </bean> <!-- mvc注解驱动 --> <mvc:annotation-driven /> </beans>
web.xml
<!--?xml version="1.0" encoding="UTF-8"?--> <web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemalocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"> <display-name></display-name> <!-- ================spring mvc 适配器================ --> <servlet> <servlet-name>springmvc</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <init-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:applicationContext.xml</param-value> </init-param> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>springmvc</servlet-name> <url-pattern>*.do</url-pattern> </servlet-mapping> <!-- ================================================== --> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list> </web-app>
多文件上传(多文件上传与单文件上传配置相同下面介绍一下不同的地方)
标记为红色的字段为多文件上传 与单文件上传的区别
@RequestMapping(value="/firstdown.do") public String doFirst(@RequestParam MultipartFile[] uploadFile,HttpSession session)throws Exception{ for (MultipartFile item : uploadFile) { if(item.getSize()>0){ //02.获取前半部分路径，jiangWebRoot下一个名称为images文件夹 转换成绝对路径 String path = session.getServletContext().getRealPath("/upload"); //01.获取文件名作为保存到服务器的文件名称 String fileName=item.getOriginalFilename(); if(fileName.endsWith(".jpg")||fileName.endsWith(".JPG")){ //03.路径拼接 File file = new File(path,fileName); item.transferTo(file); } return "welcome.jsp"; } } return "error.jsp"; }
文件下载
<br> public static void download(HttpServletRequest request, HttpServletResponse response, String storeName, String contentType ) throws Exception { request.setCharacterEncoding("UTF-8"); BufferedInputStream bis = null; BufferedOutputStream bos = null; //获取项目根目录 String ctxPath = request.getSession().getServletContext() .getRealPath(""); //获取下载文件露肩 String downLoadPath = ctxPath+"/uploadFile/"+ storeName; //获取文件的长度 long fileLength = new File(downLoadPath).length(); //设置文件输出类型 response.setContentType("application/octet-stream"); response.setHeader("Content-disposition", "attachment; filename=" + new String(storeName.getBytes("utf-8"), "ISO8859-1")); //设置输出长度 response.setHeader("Content-Length", String.valueOf(fileLength)); //获取输入流 bis = new BufferedInputStream(new FileInputStream(downLoadPath)); //输出流 bos = new BufferedOutputStream(response.getOutputStream()); byte[] buff = new byte[2048]; int bytesRead; while (-1 != (bytesRead = bis.read(buff, 0, buff.length))) { bos.write(buff, 0, bytesRead); } //关闭流 bis.close(); bos.close(); }
下载直接访问控制器如：http:\\localhost:8080/springmvc/download.do
或者通过JSP页面
<a href="./downloadFile/download" >下载</a>
