Java Upload file

Two jar packages required

Commons-fileupload-1.2.2.jar and Commons-io-2.4.jar

The form format must be

<form action= "fileupload.jsp" method= "post" enctype= "Multipart/form-data" >

An example of accepting a file

<% @pageImport= "Java.io.File"%><% @pageImport= "Org.apache.commons.fileupload.FileItem"%><% @pageImport= "Org.apache.commons.fileupload.servlet.ServletFileUpload"%><% @pageImport= "org.apache.commons.fileupload.disk.DiskFileItemFactory"%><%@ 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" >request.setcharacterencoding ("Utf-8"); String Uploadpath= "D:/upload"; //file Folder=new file ("Upload");Diskfileitemfactory factory=Newdiskfileitemfactory (); Factory.setsizethreshold (30*1024);        Factory.setrepository (Factory.getrepository ()); Servletfileupload Upload=Newservletfileupload (Factory); intmaxsize=5*1024*1024; List List=upload.parserequest (Request); Iterator Iterator=List.iterator ();  while(Iterator.hasnext ()) {Fileitem Item=(Fileitem) iterator.next (); if(!Item.isformfield ()) {String FilePath=Item.getname (); if(filepath!=NULL) {File filename=NewFile (Item.getname ()); }                if(Item.getsize () >maxsize) {Out.print ("The file is too large to be more than 5M");  Break; } File saveFile=NewFile (Uploadpath,filepath);                Item.write (SaveFile); Out.print ("File Upload succeeded"); } response.sendredirect ("Success.jsp"); }             %> </body>
Prohibit uploading of files of the specified type:
<% @pageImport= "Org.apache.commons.io.filefilter.SuffixFileFilter"%><% @pageImport= "Java.io.File"%><% @pageImport= "Org.apache.commons.fileupload.FileItem"%><% @pageImport= "Org.apache.commons.fileupload.servlet.ServletFileUpload"%><% @pageImport= "org.apache.commons.fileupload.disk.DiskFileItemFactory"%><%@ 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" >request.setcharacterencoding ("Utf-8"); String Uploadpath= "D:/upload"; //file Folder=new file ("Upload");Diskfileitemfactory factory=Newdiskfileitemfactory (); Factory.setsizethreshold (30*1024);        Factory.setrepository (Factory.getrepository ()); Servletfileupload Upload=Newservletfileupload (Factory); intmaxsize=5*1024*1024; List List=upload.parserequest (Request); string[] Limit = new string[]{". exe", "Dat"}; Suffixfilefilter filter = new suffixfilefilter (limit); Iterator Iterator=List.iterator ();  while(Iterator.hasnext ()) {Fileitem Item=(Fileitem) iterator.next (); if(!Item.isformfield ()) {String FilePath=Item.getname (); if(filepath!=NULL) {File filename=NewFile (Item.getname ()); }                if(Item.getsize () >maxsize) {Out.print ("The file is too large to be more than 5M");  Break; } File saveFile=NewFile (Uploadpath,filepath); BooleanFlag =filter.accept (SaveFile); if(flag) {Out.print ("Error");  Break; }Else{item.write (saveFile); Out.print ("File Upload succeeded");                            }; } response.sendredirect ("Success.jsp"); }             %> </body>

 
  
 
For property enctype of form forms, the default value application/x-www-form-urlencoded is typically used, which allows the form element values to be obtained through the request object's GetParameter () method. However, the Enctype property of the form is set to Multipart/form-data in the file field, which is not available through the GetParameter () method.
An example is described below
Upload page
<%          new  Date ();           = String.Format ("%TF", now);        %>    <form action= "fileupload.jsp" method= "post" enctype= "Multipart/form-data" >         Select Document < Input type= "file" Name= "File1" size= ">         uploader <input type=" text "name=" name "size=" > "        document name <input type= "text" name= "filenames" size= ">         upload time <input type=" text "name = "UpTime" value= "<%=time%>" >        <input type= "Submit" value= "Submit"/>    </form>
Working with pages
<%String name=NULL, filenames=NULL, uptime=NULL, meg=NULL; Request.setcharacterencoding ("Utf-8"); String Uploadpath= "D:/upload"; Diskfileitemfactory Factory=Newdiskfileitemfactory (); Factory.setsizethreshold (30*1024);        Factory.setrepository (Factory.getrepository ()); Servletfileupload Upload=Newservletfileupload (Factory); intMaxSize = 5*1024*1024; List List=upload.parserequest (Request); Iterator Iterator=List.iterator ();  while(Iterator.hasnext ()) {Fileitem Item=(Fileitem) iterator.next (); if(!Item.isformfield ()) {String FilePath=Item.getname (); if(filepath!=NULL) {File filename=NewFile (Item.getname ()); }                if(Item.getsize () >maxsize) {Meg= "Too Big";  Break; } File saveFile=NewFile (Uploadpath, FilePath);                Item.write (SaveFile); Meg= "Success"; }Else{String FormName=Item.getfieldname (); String Formcon= Item.getstring ("Utf-8"); if(Formname.equals ("name") ) {Name=Formcon; }                    Else if(Formname.equals ("filenames") ) {filenames=Formcon; }                Else if(Formname.equals ("UpTime") ) {UpTime=Formcon; }}} Request.setattribute ("Meg", Meg); Request.setattribute ("Name", name); Request.setattribute ("Filenames", filenames); Request.setattribute ("Uptime", UpTime); Request.getrequestdispatcher ("Success.jsp"). Forward (request, response); %>
Success Page
<body>        ${requestscope.meg}        ${requestscope.name}        ${requestscope.filenames}        ${ Requestscope.uptime}  </body>
Java Upload file