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>