Java实现上传和下载功能（支持多个文件同时上传）

Java实现上传和下载功能（支持多个文件同时上传）

文件上传一直是Web项目中必不可少的一项功能。

项目结构如下：（这是我之前创建的SSM整合的框架项目，在这上面添加文件上传与下载）

主要的是FileUploadController，doupload.jsp,up.jsp,springmvc.xml

1.先编写up.jsp

上传者：

选择文件：

选择文件：

以上便是up.jsp的核心代码；

2.编写doupload.jsp

<%

request.setCharacterEncoding("utf-8");

String uploadFileName = ""; //上传的文件名

String fieldName = ""; //表单字段元素的name属性值

//请求信息中的内容是否是multipart类型

boolean isMultipart = ServletFileUpload.isMultipartContent(request);

//上传文件的存储路径（服务器文件系统上的绝对文件路径）

String uploadFilePath = request.getSession().getServletContext().getRealPath("upload/" );

if (isMultipart) {

FileItemFactory factory = new DiskFileItemFactory();

ServletFileUpload upload = new ServletFileUpload(factory);

try {

//解析form表单中所有文件

List items = upload.parseRequest(request);

Iterator iter = items.iterator();

while (iter.hasNext()) { //依次处理每个文件

FileItem item = (FileItem) iter.next();

if (item.isFormField()){ //普通表单字段

fieldName = item.getFieldName(); //表单字段的name属性值

if (fieldName.equals("user")){

//输出表单字段的值

out.print(item.getString("UTF-8")+"上传了文件。
");

}

}else{ //文件表单字段

String fileName = item.getName();

if (fileName != null && !fileName.equals("")) {

File fullFile = new File(item.getName());

File saveFile = new File(uploadFilePath, fullFile.getName());

item.write(saveFile);

uploadFileName = fullFile.getName();

out.print("上传成功后的文件名是："+uploadFileName);

out.print("\t\t下载链接:"+""+uploadFileName+"");

out.print("
");

}

}

}

} catch (Exception e) {

e.printStackTrace();

}

}

%>

该页面主要是内容是，通过解析request，并设置上传路径，创建一个迭代器，先进行判空，再通过循环来实现多个文件的上传，再输出文件信息的同时打印文件下载路径。

效果图：

3.编写FilterController实现文件下载的功能（相对上传比较简单）：

@Controller

public class FileUploadController {

@RequestMapping(value="/download")

public ResponseEntity download(HttpServletRequest request,HttpServletResponse response,@RequestParam("name") String filename)throws Exception {

//下载显示的文件名，解决中文名称乱码问题

filename=new String(filename.getBytes("iso-8859-1"),"UTF-8");

//下载文件路径

String path = request.getServletContext().getRealPath("/upload/");

File file = new File(path + File.separator + filename);

HttpHeaders headers = new HttpHeaders();

//下载显示的文件名，解决中文名称乱码问题

String downloadFielName = new String(filename.getBytes("iso-8859-1"),"UTF-8");

//通知浏览器以attachment（下载方式）打开图片

headers.setContentDispositionFormData("Content-Disposition", downloadFielName);

//application/octet-stream ： 二进制流数据（最常见的文件下载）。

headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);

return new ResponseEntity(FileUtils.readFileToByteArray(file),

headers, HttpStatus.CREATED);

}

}

4.实现上传文件的功能还需要在springmvc中配置bean：

class="org.springframework.web.multipart.commons.CommonsMultipartResolver">

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class="org.springframework.web.multipart.commons.CommonsMultipartResolver">

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完整代码如下：

up.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>

上传者：

选择文件：

选择文件：

doupload.jsp

<%@ page language="java" pageEncoding="UTF-8"%>

<%@page import="java.io.*,java.util.*"%>

<%@page import="org.apache.commons.fileupload.*"%>

<%@page import="org.apache.commons.fileupload.disk.DiskFileItemFactory" %>

<%@page import="org.apache.commons.fileupload.servlet.ServletFileUpload"%>

<%

request.setCharacterEncoding("utf-8");

String uploadFileName = ""; //上传的文件名

String fieldName = ""; //表单字段元素的name属性值

//请求信息中的内容是否是multipart类型

boolean isMultipart = ServletFileUpload.isMultipartContent(request);

//上传文件的存储路径（服务器文件系统上的绝对文件路径）

String uploadFilePath = request.getSession().getServletContext().getRealPath("upload/" );

if (isMultipart) {

FileItemFactory factory = new DiskFileItemFactory();

ServletFileUpload upload = new ServletFileUpload(factory);

try {

//解析form表单中所有文件

List items = upload.parseRequest(request);

Iterator iter = items.iterator();

while (iter.hasNext()) { //依次处理每个文件

FileItem item = (FileItem) iter.next();

if (item.isFormField()){ //普通表单字段

fieldName = item.getFieldName(); //表单字段的name属性值

if (fieldName.equals("user")){

//输出表单字段的值

out.print(item.getString("UTF-8")+"上传了文件。
");

}

}else{ //文件表单字段

String fileName = item.getName();

if (fileName != null && !fileName.equals("")) {

File fullFile = new File(item.getName());

File saveFile = new File(uploadFilePath, fullFile.getName());

item.write(saveFile);

uploadFileName = fullFile.getName();

out.print("上传成功后的文件名是："+uploadFileName);

out.print("\t\t下载链接:"+""+uploadFileName+"");

out.print("
");

}

}

}

} catch (Exception e) {

e.printStackTrace();

}

}

%>

FileUploadController.java

package ssm.me.controller;

import java.io.File;

import java.net.URLDecoder;

import java.util.Iterator;

import java.util.List;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import org.apache.commons.fileupload.FileItem;

import org.apache.commons.fileupload.FileItemFactory;

import org.apache.commons.fileupload.disk.DiskFileItemFactory;

import org.apache.commons.fileupload.servlet.ServletFileUpload;

import org.apache.commons.io.FileUtils;

import org.junit.runners.Parameterized.Parameter;

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.ModelAttribute;

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

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

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

import org.springframework.web.multipart.MultipartFile;

@Controller

public class FileUploadController {

@RequestMapping(value="/download")

public ResponseEntity download(HttpServletRequest request,HttpServletResponse response,@RequestParam("name") String filename)throws Exception {

//下载显示的文件名，解决中文名称乱码问题

filename=new String(filename.getBytes("iso-8859-1"),"UTF-8");

//下载文件路径

String path = request.getServletContext().getRealPath("/upload/");

File file = new File(path + File.separator + filename);

HttpHeaders headers = new HttpHeaders();

//下载显示的文件名，解决中文名称乱码问题

String downloadFielName = new String(filename.getBytes("iso-8859-1"),"UTF-8");

//通知浏览器以attachment（下载方式）打开图片

headers.setContentDispositionFormData("Content-Disposition", downloadFielName);

//application/octet-stream ： 二进制流数据（最常见的文件下载）。

headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);

return new ResponseEntity(FileUtils.readFileToByteArray(file),

headers, HttpStatus.CREATED);

}

}

SpringMVC.xml（仅供参考，有的地方不可以照搬）

xmlns:xsi="http://w3.org/2001/XMLSchema-instance"

xmlns:mvc="http://springframework.org/schema/mvc"

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

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

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

xsi:schemaLocation="http://springframework.org/schema/beans

http://springframework.org/schema/beans/spring-beans-4.2.xsd

http://springframework.org/schema/mvc

http://springframework.org/schema/mvc/spring-mvc-4.2.xsd

http://springframework.org/schema/context

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

http://springframework.org/schema/aop

http://springframework.org/schema/aop/spring-aop-4.2.xsd

http://springframework.org/schema/tx

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

class="org.springframework.web.multipart.commons.CommonsMultipartResolver">

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xmlns:xsi="http://w3.org/2001/XMLSchema-instance"

xmlns:mvc="http://springframework.org/schema/mvc"

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

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

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

xsi:schemaLocation="http://springframework.org/schema/beans

http://springframework.org/schema/beans/spring-beans-4.2.xsd

http://springframework.org/schema/mvc

http://springframework.org/schema/mvc/spring-mvc-4.2.xsd

http://springframework.org/schema/context

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

http://springframework.org/schema/aop

http://springframework.org/schema/aop/spring-aop-4.2.xsd

http://springframework.org/schema/tx

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

class="org.springframework.web.multipart.commons.CommonsMultipartResolver">

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class="org.springframework.web.multipart.commons.CommonsMultipartResolver">

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web.xml（仅供参考，有的地方不可以照搬）

Student

index.html

index.htm

index.jsp

default.html

default.htm

default.jsp

springmvc

org.springframework.web.servlet.DispatcherServlet

contextConfigLocation

classpath:springmvc.xml

1

springmvc

*.action

contextConfigLocation

classpath:spring/applicationContext-*.xml

org.springframework.web.context.ContextLoaderListener

以上便为文件上传和下载的全部代码，博主亲测过，没有问题。

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