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