SpringMVC文件上传和下载

上传与下载

1文件上传

1.1加入jar包

文件上传需要依赖的jar包

1.2配置部件解析器

解析二进制流数据。

 <?xml version="1.0" encoding="UTF-8"?>
 <!-- 到入xml文件的约束 -->

 <beans xmlns="http://www.springframework.org/schema/beans"
     xmlns:context="http://www.springframework.org/schema/context"
     xmlns:mvc="http://www.springframework.org/schema/mvc"
     xmlns:p="http://www.springframework.org/schema/p"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://www.springframework.org/schema/beans
      http://www.springframework.org/schema/beans/spring-beans-4.1.xsd
      http://www.springframework.org/schema/context
      http://www.springframework.org/schema/context/spring-context-4.1.xsd
       http://www.springframework.org/schema/mvc
      http://www.springframework.org/schema/mvc/spring-mvc-4.1.xsd
      ">

       <!-- 开启注解扫描（将对象纳入spring容器） -->
       <context:component-scan base-package="org.guangsoft.controller">
       </context:component-scan> 

      <!-- 开始springmvc的映射注解和适配注解 -->
      <mvc:annotation-driven></mvc:annotation-driven>

      <!-- 实例化文件上传的解析器（MIME） -->
      <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>

 </beans> 

1.3建立FileController

 package org.guangsoft.controller;
 import java.io.File;
 import java.io.IOException;
 import java.util.UUID;
 import javax.servlet.http.HttpSession;
 import org.apache.commons.io.FileUtils;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
 import org.springframework.http.ResponseEntity;
 import org.springframework.stereotype.Controller;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.multipart.commons.CommonsMultipartFile;
 @Controller
 public class FileController
 {
     /***
      * 实现文件的上传
      *
      * @RequestParam:指定客户端发送数据的名字
      * **/
     @RequestMapping("/uploadFile")
     public String uploadFile(@RequestParam("cmf") CommonsMultipartFile cmf,
             HttpSession session)
     {
         // 1获得上传的文件内容
         byte[] bytes = cmf.getBytes();
         // 2获得upload的绝对路径
         String path = session.getServletContext().getRealPath("/upload");
         // 3在服务器的upload目录下创建File对象
         String oname = cmf.getOriginalFilename(); // 上传文件的原始名字
         String uuid = UUID.randomUUID().toString();
         File file = new File(path, uuid
                 + oname.substring(oname.lastIndexOf(".")));
         // 4将上传的文件拷贝到指定的目录
         try
         {
             FileUtils.writeByteArrayToFile(file, bytes);
         }
         catch (IOException e)
         {
             e.printStackTrace();
         }
         return "index.jsp";
     }
     /***
      * 实现文件下载
      * ***/
     @RequestMapping("/download")
     public ResponseEntity download(HttpSession session)
     {
         // 用来封装响应头信息
         HttpHeaders responseHeaders = new HttpHeaders();
         // 下载的附件的类型
         responseHeaders.setContentType(MediaType.APPLICATION_OCTET_STREAM);
         // 下载的附件的名称
         responseHeaders.setContentDispositionFormData("attachment", "1.png");
         String path = session.getServletContext().getRealPath("/upload");
         String fname = "b8abd107-ecdd-49ae-9175-b39f1d18a288.png"; // 数据库查询获得
         // 将下载的文件封装流对象
         File file = new File(path, fname);
         try
         {
             /**
              * arg1:需要响应到客户端的数据 arg2:设置本次请求的响应头 arg3:响应到客户端的状态码
              * ***/
             return new ResponseEntity(FileUtils.readFileToByteArray(file),
                     responseHeaders, HttpStatus.CREATED);
         }
         catch (IOException e)
         {
             e.printStackTrace();
         }
         return null;
     }
 } 

1.4建立视图页面

 <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
 <%
 String path = request.getContextPath();
 String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
 %>

 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
 <html>
   <head>
     <base href="<%=basePath%>">
     <title>upload</title>
     <meta http-equiv="pragma" content="no-cache">
     <meta http-equiv="cache-control" content="no-cache">
     <meta http-equiv="expires" content="0">
     <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
     <meta http-equiv="description" content="This is my page">
   </head>

   <body>
     <form action="uploadFile.action" method="post"
         enctype="multipart/form-data">
         <div>file<input name="cmf" type="file"/></div>
         <div> <input type="submit" value="提交"/></div>
     </form>
     <hr/>
     <a href="download.action">下载</a>
   </body>
 </html> 

2 文件下载

2.1建立下的handler方法

见上