用SpringMVC实现的上传下载方式二(多文件上传)

2022-10-14 15:35:05

参考来源： http://blog.csdn.net/qq_32953079/article/details/52290208

1、导入相关jar包

commons-fileupload.jar

commons-io.jar

2、配置web.xml文件

<?xml version="1.0" encoding="UTF-8"?>

<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">

  <display-name>SpringMVC_fileUpLoad</display-name>

  <welcome-file-list>

    <welcome-file>index.html</welcome-file>

    <welcome-file>index.htm</welcome-file>

    <welcome-file>index.jsp</welcome-file>

    <welcome-file>default.html</welcome-file>

    <welcome-file>default.htm</welcome-file>

    <welcome-file>default.jsp</welcome-file>

  </welcome-file-list>

  	<filter>

		<filter-name>encodingFilter</filter-name>

		<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>

		<init-param>

			<param-name>encoding</param-name>

			<param-value>UTF-8</param-value>

		</init-param>

	</filter>

	<filter-mapping>

		<filter-name>encodingFilter</filter-name>

		<url-pattern>/*</url-pattern>

	</filter-mapping>

	<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:springmvc-servlet.xml</param-value>

		</init-param>

		<load-on-startup>1</load-on-startup>

	</servlet>

	<servlet-mapping>

		<servlet-name>springmvc</servlet-name>

		<url-pattern>*.action</url-pattern>

	</servlet-mapping>

</web-app>

3、编写上传页面

<%@ page language="java" contentType="text/html; charset=UTF-8"

    pageEncoding="UTF-8"%>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<html>

<head>

<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

<title>Insert title here</title>

</head>

<body>

<h1>多文件上传</h1>

<form action="upload.action" method="post"enctype="multipart/form-data">

	<input type="file" name="pic" /><br/>

	<input type="file" name="pic" /><br/>

	<input type="file" name="pic" /><br/>

	<input type="file" name="pic" /><br/>

	<input type="submit" value="上传" />

</form>

</body>

</html>

4、配置springmvc-servlet.xml

<?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:mvc="http://www.springframework.org/schema/mvc"

	xmlns:aop="http://www.springframework.org/schema/aop"

	xmlns:tx="http://www.springframework.org/schema/tx"

	xmlns:context="http://www.springframework.org/schema/context"

	xmlns:c="http://www.springframework.org/schema/c"

	xmlns:cache="http://www.springframework.org/schema/cache"

	xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd

		http://www.springframework.org/schema/cache http://www.springframework.org/schema/cache/spring-cache-4.0.xsd

		http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd

		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd

		http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd

		http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd">

	<context:component-scan base-package="com.etc"></context:component-scan>

	<bean id="fileUpLoadController" class="com.etc.fileupload.FileUpLoadController"/>

   <!-- 文件上传的配置               CommonsMultipartResolver公共上传解析器 -->

   <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">

       <!-- 指定所上传文件的总大小不能超过200KB。注意maxUploadSize属性的限制不是针对单个文件，而是所有文件的容量之和 -->

       <!-- <property name="maxUploadSize" value="200000"/>    出错原因1：图片大小限制-->

       <property name="maxUploadSize" value="10240000"/>

   </bean>     

   <!-- 该异常是SpringMVC在检查上传的文件信息时抛出来的，而且此时还没有进入到Controller方法中 -->

   <bean id="exceptionResolver" class="org.springframework.web.servlet.handler.SimpleMappingExceptionResolver">

       <property name="exceptionMappings">

           <props>

               <!-- 遇到MaxUploadSizeExceededException异常时，自动跳转到WebContent目录下的error.jsp页面 -->

               <prop key="org.springframework.web.multipart.MaxUploadSizeExceededException">error.jsp</prop>

           </props>

       </property>

	</bean>

</beans>

5、编写handler处理器

package com.etc.fileupload;

/**

 * 上传和下载的区别：

 * 上传是将文件上传到服务器中，而下载是将服务器中的文件下载到本地环境中

 *

 * 回去后，用自己电脑作为服务器，其他电脑作为用户电脑，在尝试一下连接

 *       查看上传到服务端的地址以及下载时客户端的地址，

 *       request.getServletContext().getRealPath("/img")貌似是请求的客户端地址，回去在研究下

 */

import java.io.File;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;

import java.util.ArrayList;

import java.util.List;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

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.ui.Model;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RequestParam;

import org.springframework.web.multipart.MultipartFile;

@Controller

public class FileUpLoadController {

	/**

	 * 多文件上传

	 * @param pic

	 * @param model

	 * @param request

	 * @return

	 * @throws IOException

	 */

	@RequestMapping("/upload.action")

	public String UpLoad(@RequestParam MultipartFile[] pic,Model model,HttpServletRequest request) throws IOException{

		System.out.println("upload.action进来了！");

		List<String> list=new ArrayList<String>();

		for(MultipartFile file:pic){

			//此处MultipartFile[]表明是多文件,如果是单文件MultipartFile就行了

			if(pic==null||file.isEmpty()){

				System.out.println("文件未上传！");

			}else{

				//得到上传的文件名

				String filename=file.getOriginalFilename();

				System.out.println("文件名：    "+filename);

				//得到服务器项目发布运行所在地址                     //出错问题二：请求地址时，要看是什么层次的请求，request和session是不同的

                String pmpath =request.getServletContext().getRealPath("/img")+File.separator;

                //String pmpath=request.getServletContext().getRealPath("/img")+ File.separator + filename;

				System.out.println("服务器项目发布所在地址：   "+pmpath);

				//此处未使用UUID来生成唯一标识(这也是正常下载的图片是很多数字命名的原因),用日期做为标识  (过会做一下)

                String path = pmpath + filename;  /*new SimpleDateFormat("yyyyMMddHHmmss").format(new Date())+*/

                //String path = UUID.randomUUID().toString();

                ////查看文件上传路径,方便查找

                System.out.println("完整的文件上传后，保存所在的路径：  "+path);

                //将每一个文件名保存到list集合中

                list.add(filename);

                //list.add(path);

                //把文件上传至path的路径

                File localFile=new File(path);

                file.transferTo(localFile);

			}

		}

		model.addAttribute("filenameList",list);

		return "uploadSuccess.jsp";

	}

	/**

	 * 文件下载实现方式一

	 * @param r

	 * @param filename

	 * @return

	 * @throws IOException

	 */

	@RequestMapping("/down.action")

	public ResponseEntity<byte[]> downFile(HttpServletRequest r,String filename) throws IOException{

		//配置http请求头文件信息

		HttpHeaders headers = new HttpHeaders();

		String path=r.getServletContext().getRealPath("/img")+ File.separator + filename;

		File file=new File(path);

	    headers.setContentDispositionFormData("attachment",filename);//不自动打开

	    headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);   //头文件内容类型

	    return new ResponseEntity<byte[]>(FileUtils.readFileToByteArray(file),

	                                       headers, HttpStatus.CREATED);

	}

	/**

	 * 文件下载实现方式二

	 * @param fileName

	 * @param request

	 * @param response

	 * @return

	 */

	@RequestMapping("/download2.action")

    public String download(String fileName, HttpServletRequest request,

            HttpServletResponse response) {

        response.setCharacterEncoding("utf-8");

        response.setContentType("multipart/form-data");

        response.setHeader("Content-Disposition", "attachment;fileName="

                + fileName);

        try {

            String path = request.getSession().getServletContext().getRealPath

                    ("image")+File.separator;

            InputStream inputStream = new FileInputStream(new File(path

                    + fileName));  

            OutputStream os = response.getOutputStream();

            byte[] b = new byte[2048];

            int length;

            while ((length = inputStream.read(b)) > 0) {

                os.write(b, 0, length);

            }

             // 这里主要关闭。

            os.close();  

            inputStream.close();

        } catch (FileNotFoundException e) {

            e.printStackTrace();

        } catch (IOException e) {

            e.printStackTrace();

        }

            //  返回值要注意，要不然就出现下面这句错误！

            //java+getOutputStream() has already been called for this response

        return null;

    }

}

6、编写下载页面

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<html>

<head>

<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

<title>Insert title here</title>

<style>

	div{

		float: left;

	}

</style>

</head>

<body>

	<h1>图片上传成功</h1>

    <!-- 图片显示问题解决，服务器上不能写绝对地址，也不能加/img这种格式，应该是img/这种格式，看看图片重复怎么解决-->

	<div style="width:600px">

	<c:forEach items="${filenameList}" var="fname">

		<div style="width:200px">

			<img src="img/${fname}" width="200px"/>

		</div>

	</c:forEach>

	</div>

	<%-- <a href="down.action?filename=${filename}">下载</a> --%>

</body>

</html>

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