This article is a custom single file upload code for a pure JSP:
<%@ page contenttype= "text/html; CHARSET=GBK "%>
<%@ page import= "java.io.*"%>
<%@ page import= "java.util.*"%>
<%@ page import= "javax.servlet.*"%>
<%@ page import= "javax.servlet.http.*"%>
<title>
Upfile
</title>
<body bgcolor= "#ffffff" >
<center>
<%
Define maximum bytes for uploaded files
int max_size = 102400 * 102400;
To create a save variable for the root path
String RootPath;
Declaring a file read into a class
DataInputStream in = null;
FileOutputStream fileout = null;
Get the client's network address
String remoteaddr = Request.getremoteaddr ();
Out.print (REMOTEADDR);
Get the name of the server
String serverName = Request.getservername ();
Out.print (ServerName);
Gets the address of the JSP file relative to the root address
Out.print (Request.getservletpath ());
Get an absolute address for an Internet program
String Realpath = Request.getrealpath (serverName);
Out.println (Realpath);
Realpath = realpath.substring
(0,realpath.lastindexof ("\"));
Out.print (Realpath);
Create the Save directory for the file "\upload"
RootPath = Realpath + "\\upload\\";
Out.println (RootPath);
Get the data type that the client uploads
String ContentType = Request.getcontenttype ();
Out.println
("<p> client uploaded data type =
"+ ContentType + </p>");
try{
if (contenttype.indexof
("Multipart/form-data") >= 0)
{
Read the uploaded data
in = new DataInputStream
(Request.getinputstream ());
int formdatalength =
Request.getcontentlength ();
if (Formdatalength > Max_size) {
Out.println
("<P> the number of bytes uploaded can not exceed"
+ max_size + "</p>");
Return
}
Save data for uploaded files
byte databytes[] = new Byte[formdatalength];
int byteread = 0;
int totalbytesread = 0;
The uploaded data is saved in the byte array
while (Totalbytesread < formdatalength)
{
Byteread = In.read (Databytes,
Totalbytesread,formdatalength);
Totalbytesread + = Byteread;
}
Create a string from a byte array
String file = new string (databytes);
Out.println (file);
Gets the file name of the uploaded data
String SaveFile = file.substring
(File.indexof ("filename=\") + 10);
SaveFile = savefile.substring
(0,savefile.indexof ("\ n"));
SaveFile = savefile.substring
(Savefile.lastindexof ("\")
+ 1,savefile.indexof ("\"));
int lastindex =
Contenttype.lastindexof ("=");
Gets the delimited string of data
String boundary =
Contenttype.substring
(Lastindex + 1,contenttype.length ());
Create a file name for the save path
String fileName = RootPath + savefile;
Out.print (FileName);
int POS;
pos = File.indexof ("filename=\");
pos = File.indexof ("\ n", POS) + 1;
pos = File.indexof ("\ n", POS) + 1;
pos = File.indexof ("\ n", POS) + 1;
int boundarylocation =
File.indexof (Boundary,pos)-4;
Out.println (boundarylocation);
Gets the location where the file data starts
int startpos = (
(File.substring (0,pos)). GetBytes ()). length;
Out.println (startpos);
Where to get the end of the file data
int endpos = ((file.substring
(0,boundarylocation)). GetBytes ()). length;
Out.println (Endpos);
Check if the uploaded file exists
File Checkfile = new file (fileName);
if (checkfile.exists ()) {
Out.println ("<p>" + SaveFile +
"File already exists .</p>");
}
Check if the directory of uploaded files exists
File Filedir = new file (RootPath);
if (!filedir.exists ())
{
Filedir.mkdirs ();
}
Create a write class for a file
Fileout = new FileOutputStream (fileName);
Save data for a file
Fileout.write (Databytes,startpos,
(Endpos-startpos));
Fileout.close ();
Out.println ("<P>" + SaveFile +
"File successfully uploaded .</p>");
}else{
String content = Request.getcontenttype ();
Out.println
("The data type of the <p> upload is not multipart/form-data</p>");
}
}catch (Exception ex)
{
throw new Servletexception (Ex.getmessage ());
}
%>
</center>
</body>
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