Wednesday, May 31, 2006

File Upload in Java

First u have to create a Web page frm which u select a file

call it FileUpload.html


<HTML>
<HEAD>
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=windows-1252"/>
<TITLE>File Upload Page</TITLE>
</HEAD>
<BODY>Upload Files
<form name="uploadForm" action="ProcessFileUpload.jsp" enctype="multipart/form-data" method="post">
<input type="file" name="file"/>
<input TYPE=Button name='Upload' Value='Upload' onClick="uploadForm.Upload.value='Uploading...';document.uploadForm.action='ProcessFileUpload.jsp';document.uploadForm.submit()">
</form>
</BODY>
</HTML>

Then create a JSp page which handles the input stream

call it ProcessFileUpload.jsp

<%

response.setContentType("text/html");
response.setHeader("Cache-control","no-cache");

String err = "";

String lastFileName = "";

String contentType = request.getContentType();
String boundary = "";
final int BOUNDARY_WORD_SIZE = "boundary=".length();
if(contentType == null || !contentType.startsWith("multipart/form-data")) {
err = "Ilegal ENCTYPE : must be multipart/form-data\n";
err += "ENCTYPE set = " + contentType;
}else{
boundary = contentType.substring(contentType.indexOf("boundary=") + BOUNDARY_WORD_SIZE);
boundary = "--" + boundary;
try {
javax.servlet.ServletInputStream sis = request.getInputStream();
byte[] b = new byte[1024];
int x=0;
int state=0;
String name=null,fileName=null,contentType2=null;
java.io.FileOutputStream buffer = null;
while((x=sis.readLine(b,0,1024))>-1) {
String s = new String(b,0,x);
if(s.startsWith(boundary)) {
state = 0;
//out.println("name="+name+"<br>");
//out.println(fileName+"<br>");

name = null;
contentType2 = null;
fileName = null;


}else if(s.startsWith("Content-Disposition") && state==0) {
state = 1;
if(s.indexOf("filename=") == -1)
name = s.substring(s.indexOf("name=") + "name=".length(),s.length()-2);
else {
name = s.substring(s.indexOf("name=") + "name=".length(),s.lastIndexOf(";"));
fileName = s.substring(s.indexOf("filename=") + "filename=".length(),s.length()-2);
if(fileName.equals("\"\"")) {
fileName = null;
}else {
String userAgent = request.getHeader("User-Agent");
String userSeparator="/"; // default
if (userAgent.indexOf("Windows")!=-1)
userSeparator="\\";
if (userAgent.indexOf("Linux")!=-1)
userSeparator="/";
fileName = fileName.substring(fileName.lastIndexOf(userSeparator)+1,fileName.length()-1);
if(fileName.startsWith( "\""))
fileName = fileName.substring( 1);
}
}
name = name.substring(1,name.length()-1);
if (name.equals("file")) {
if (buffer!=null)
buffer.close();
lastFileName = fileName;
buffer = new java.io.FileOutputStream(application.getRealPath("/")+"/"+fileName);
}
}else if(s.startsWith("Content-Type") && state==1) {
state = 2;
contentType2 = s.substring(s.indexOf(":")+2,s.length()-2);
}else if(s.equals("\r\n") && state != 3) {
state = 3;
}else {
if (name.equals("file"))
buffer.write(b,0,x);
}
}
sis.close();
buffer.close();
}catch(java.io.IOException e) {
err = e.toString();
}
}
boolean ok = err.equals("");
if(!ok) {
out.println(err);
}else{
%>
<SCRIPT language="javascript">
history.back(1)
alert('Uploaded <%=lastFileName%>');
window.location.reload(false)
</SCRIPT>
<%
}
out.println("done");
%>


This code uploads file in the home directory of ur context.This has been define in Scriplet

java.io.FileOutputStream(application.getRealPath("/")+"/"+fileName);