JSP实现任意个文件上传

使用commons-fileupload实现单个和多个文件上传

对于实现文件上传功能来说,Commons-fileupload组件是一个不错的选择,本文使用它实现了单个文件及多个文件上传,这里将实现过程写出来与大家共享。

1.单个文件上传。
页面代码:

<!--<br /> <br /> Code highlighting produced by Actipro CodeHighlighter (freeware)<br /> http://www.CodeHighlighter.com/<br /> <br /> -->
....
< div id ="content" >
< fieldset >< legend > 下載列表 </ legend >
< ul >
<%
List
< String > downloadList = (List < String > )request.getAttribute( " downloadList " );

if (downloadList! = null ){
for ( String str:downloadList){
out.print(
" <li><ahref='DownloadFile?file= " + str + " '> " + str + " </a></li> " );
}
}
%>
</ ul >
</ fieldset >

<!-- enctype属性为表单定义了MIME编码方式,上传文件的表单enctype属性必须如此设置 -->
< form method ="post" action ="UploadFile" enctype ="multipart/form-data" >
< p >< input type ="text" name ="fileIntro" value ="" /> 文件介绍 </ p >
< p >< input type ="file" name ="myfile1" value ="浏览文件" /></ p >
< p >< input type ="submit" value ="上传" /></ p >
</ form >
</ div >....

在上传表单中,既有普通文本域也有文件上传域,注意在Servlet中取它们和平常的做法不同:
Servlet代码:

<!--<br /> <br /> Code highlighting produced by Actipro CodeHighlighter (freeware)<br /> http://www.CodeHighlighter.com/<br /> <br /> --> package com.sitinspring.action;

import
java.io.File;
import
java.util.ArrayList;
import
java.util.Iterator;
import
java.util.List;

import
javax.servlet.RequestDispatcher;
import
javax.servlet.ServletException;
import
javax.servlet.http.HttpServlet;
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
com.sitinspring.util.UploadUtil;

/**

*用于文件上传处理的Servlet
*
@author sitinspring
*
*@date2008-2-12
*/

publicclassUploadFileServletextends HttpServlet{
privatestaticfinallongserialVersionUID=56890894234786L
;

@SuppressWarnings(
"unchecked"
)
publicvoid
doPost(HttpServletRequestrequest,HttpServletResponseresponse)
throws
ServletException,java.io.IOException{
request.setCharacterEncoding(
"UTF-8"
);

//文件上傳部分

booleanisMultipart= ServletFileUpload.isMultipartContent(request);

if(isMultipart==true
){
try
{
FileItemFactoryfactory
=new
DiskFileItemFactory();
ServletFileUploadupload
=new
ServletFileUpload(factory);

//得到所有的表单域,它们目前都被当作FileItem

List<FileItem>fileItems= upload.parseRequest(request);
Iterator
<FileItem>iter=
fileItems.iterator();

//依次处理每个表单域

while (iter.hasNext()){
FileItemitem
=
(FileItem)iter.next();

if
(item.isFormField()){
//如果item是正常的表单域

Stringname= item.getFieldName();
Stringvalue
=
item.getString();
System.out.print(
"表单域名为:"+name+"表单域值为:"+
value);
}
else
{
//
如果item是文件上传表单域

//获得文件名及路径

StringfileName= item.getName();
if(fileName!=null
){
FilefullFile
=new
File(item.getName());

//如果文件存在则上传

if (fullFile.exists()){
FilefileOnServer
=new
File(UploadUtil.getUploadPath(),
fullFile.getName());
item.write(fileOnServer);

System.out.println(
"文件"+fileOnServer.getName()+"上传成功"
);
}
}
}
}
}
catch
(Exceptione){
e.printStackTrace();
}
}
else
{
System.out.println(
"theenctypemustbemultipart/form-data"
);
}

//取得服务器中已有文件的下載列表

List<String>fileListInServer=newArrayList<String> ();

Filedir
=new
File(UploadUtil.getUploadPath());
String[]children
=
dir.list();
if(children!=null
){
for(inti=0;i<children.length;i++
){
fileListInServer.add(children[i]);
}
}

request.setAttribute(
"downloadList"
,fileListInServer);

//跳回原頁面

RequestDispatcherdispatcher= request
.getRequestDispatcher(
"/web/page/uploadtoserver.jsp"
);
dispatcher.forward(request,response);
return
;
}

publicvoid
doGet(HttpServletRequestrequest,HttpServletResponseresponse)
throws
ServletException,java.io.IOException{
doPost(request,response);
}
}


从上面的代码可以看出,无论是否文件上传表单域都被当成了FileItem来处理,要区别开来使用isFormField()方法即可,返回真是常规表单域,返回假则是文件上传表单域。

2.多个文件上传到服务器端。

这里采用JS动态生成几个文件上传表单域即可,Servlet无需改变。
多文件上传页面代码如下:

<!--<br /> <br /> Code highlighting produced by Actipro CodeHighlighter (freeware)<br /> http://www.CodeHighlighter.com/<br /> <br /> --> <% @pagecontentType = " text/html;charset=UTF-8 " %>
<% @pagelanguage = " java " import = " java.util.List " %>

<! DOCTYPEHTMLPUBLIC"-//W3C//DTDHTML4.0Transitional//EN" >
< html >
< head >
< title > 上传多個文件到服务器 </ title >
< meta http-equiv ="Content-Type" content ="text/html;charset=UTF-8" >
< link rel ="stylesheet" rev ="stylesheet" href ="web/css/style.css"
type
="text/css" />
</ head >

< body >
< div id ="bodyDiv" >
< div id ="header" >
< jsp:include page ="/web/page/branch/header.jsp" />
</ div >
< div id ="sidebar" >
< jsp:include page ="/web/page/branch/sidebar.jsp" />
</ div >
< div id ="content" >
< fieldset >< legend > 下載列表 </ legend >
< ul >
<%
List
< String > downloadList = (List < String > )request.getAttribute( " downloadList " );

if (downloadList! = null ){
for ( String str:downloadList){
out.print(
" <li><ahref='DownloadFile?file= " + str + " '> " + str + " </a></li> " );
}
}
%>
</ ul >
</ fieldset >

<!-- enctype属性为表单定义了MIME编码方式,上传文件的表单enctype属性必须如此设置 -->
< form name ="uploadForm" method ="post" action ="UploadFile" enctype ="multipart/form-data" >
< p >< input type ="button" value ="增加上传按钮" onclick ="addUploadButton()" /></ p >
< p >< input type ="file" name ="myfile1" value ="浏览文件" /></ p >
< p >< input type ="submit" value ="上传" /></ p >
</ form >
</ div >
< div id ="footer" >
< jsp:include page ="/web/page/branch/footer.jsp" />
</ div >
</ div >
</ body >


JS代码:

<!--<br /> <br /> Code highlighting produced by Actipro CodeHighlighter (freeware)<br /> http://www.CodeHighlighter.com/<br /> <br /> --> < scriptLANGUAGE = " JavaScript " >
<!--
var count = 1 ;

function addUploadButton(){
// 按ID找到FOrm
var uploadForm = document.getElementById( " uploadForm " );

// 创建P元素
var pNode = document.createElement( " p " );

// 累加Count以观察次数
count = count + 1 ;

pNode.innerHTML
= " <inputtype='file'name='myfile " + count + " 'value='浏览文件'/> " ;

// 将P元素添加到body中
uploadForm.appendChild(pNode);
}

// -->
</ script >
</ html >

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