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file transfer in servlet programming.

P: 5
hi everybody!
iam facing a problem with the transfer of file using servlet programming. i have a code for uploading a file. but i'm unable to execute it using tomcat5.5 server. kindly help me how to execute it using tomcat server5.5.
the code is as follows.

if you have any other coding regarding this, please send me.it's urgent.

import java.io.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;
//import grid.*;
public class UploadTest extends HttpServlet {
public void doPost(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException {
res.setContentType("text/html");
PrintWriter out = res.getWriter();
try {
// Blindly take it on faith this is a multipart/form-data request
// Construct a MultipartRequest to help read the information.
// Pass in the request, a directory to save files to, and the
// maximum POST size we should attempt to handle.
// Here we (rudely) write to the server root and impose 5 Meg limit.
MultipartRequest multi = new MultipartRequest(req, ".", 5 * 1024 * 1024);
out.println("<HTML>");
out.println("<HEAD><TITLE>UploadTest</TITLE></HEAD>");
out.println("<BODY>");
out.println("<H1>UploadTest</H1>");
// Print the parameters we received
out.println("<H3>Params:</H3>");
out.println("<PRE>");
Enumeration params = multi.getParameterNames();
while (params.hasMoreElements()) {
String name = (String)params.nextElement();
String value = multi.getParameter(name);
out.println(name + " = " + value);
}
out.println("</PRE>");
// Show which files we received
out.println("<H3>Files:</H3>");
out.println("<PRE>");
Enumeration files = multi.getFileNames();
while (files.hasMoreElements()) {
String name = (String)files.nextElement();
String filename = multi.getFilesystemName(name);
String type = multi.getContentType(name);
File f = multi.getFile(name);
out.println("name: " + name);
out.println("filename: " + filename);
out.println("type: " + type);
if (f != null) {
out.println("length: " + f.length());
out.println();
}
out.println("</PRE>");
}
}
catch (Exception e) {
out.println("<PRE>");
e.printStackTrace(out);
out.println("</PRE>");
}
out.println("</BODY></HTML>");
}
}





class MultipartRequest {
private static final int DEFAULT_MAX_POST_SIZE = 1024 * 1024;
private ServletRequest req;
private File dir;
private int maxSize;
private Hashtable parameters = new Hashtable(); // name - value
private Hashtable files = new Hashtable(); // name - UploadedFile



public MultipartRequest(ServletRequest request,String saveDirectory) throws IOException {
//this(request, saveDirectory, DEFAULT_MAX_POST_SIZE);

}



public MultipartRequest(ServletRequest request,String saveDirectory,int maxPostSize) throws IOException {
// Sanity check values
if (request == null)
throw new IllegalArgumentException("request cannot be null");
if (saveDirectory == null)
throw new IllegalArgumentException("saveDirectory cannot be null");
if (maxPostSize <= 0) {
throw new IllegalArgumentException("maxPostSize must be positive");
}
// Save the request, dir, and max size
req = request;
dir = new File(saveDirectory);
maxSize = maxPostSize;
// Check saveDirectory is truly a directory
if (!dir.isDirectory())
throw new IllegalArgumentException("Not a directory: " + saveDirectory);
// Check saveDirectory is writable
if (!dir.canWrite())
throw new IllegalArgumentException("Not writable: " + saveDirectory);
// Now parse the request saving data to "parameters" and "files";
// write the file contents to the saveDirectory

readRequest();
}



public Enumeration getParameterNames() {
return parameters.keys();
}



public Enumeration getFileNames() {
return files.keys();
}



public String getParameter(String name) {
try {
String param = (String)parameters.get(name);
if (param.equals("")) return null;
return param;
}
catch (Exception e) {
return null;
}
}



public String getFilesystemName(String name) {
try {
UploadedFile file = (UploadedFile)files.get(name);
return file.getFilesystemName(); // may be null
}
catch (Exception e) {
return null;
}
}



public String getContentType(String name) {
try {
UploadedFile file = (UploadedFile)files.get(name);
return file.getContentType(); // may be null
}
catch (Exception e) {
return null;
}
}



public File getFile(String name) {
try {
UploadedFile file = (UploadedFile)files.get(name);
return file.getFile(); // may be null
}
catch (Exception e) {
return null;
}
}



protected void readRequest() throws IOException {
// Check the content type to make sure it's "multipart/form-data"
String type = req.getContentType();
if (type == null ||
!type.toLowerCase().startsWith("multipart/form-data")) {
throw new IOException("Posted content type isn't multipart/form-data");
}
// Check the content length to prevent denial of service attacks
int length = req.getContentLength();
if (length > maxSize) {
throw new IOException("Posted content length of " + length +
" exceeds limit of " + maxSize);
}
// Get the boundary string; it's included in the content type.
// Should look something like "------------------------12012133613061"
String boundary = extractBoundary(type);
if (boundary == null) {
throw new IOException("Separation boundary was not specified");
}
// Construct the special input stream we'll read from
MultipartInputStreamHandler in =new MultipartInputStreamHandler(req.getInputStream(), boundary, length);
// Read the first line, should be the first boundary
String line = in.readLine();
if (line == null) {
throw new IOException("Corrupt form data: premature ending");
}
// Verify that the line is the boundary
if (!line.startsWith(boundary)) {
throw new IOException("Corrupt form data: no leading boundary");
}
// Now that we're just beyond the first boundary, loop over each part
boolean done = false;
while (!done) {
done = readNextPart(in, boundary);
}
}



protected boolean readNextPart(MultipartInputStreamHandler in,
String boundary) throws IOException {
// Read the first line, should look like this:
// content-disposition: form-data; name="field1"; filename="file1.txt"
String line = in.readLine();
if (line == null) {
// No parts left, we're done
return true;
}
// Parse the content-disposition line
String[] dispInfo = extractDispositionInfo(line);
String disposition = dispInfo[0];
String name = dispInfo[1];
String filename = dispInfo[2];
// Now onto the next line. This will either be empty
// or contain a Content-Type and then an empty line.
line = in.readLine();
if (line == null) {
// No parts left, we're done
return true;
}
// Get the content type, or null if none specified
String contentType = extractContentType(line);
if (contentType != null) {
// Eat the empty line
line = in.readLine();
if (line == null || line.length() > 0) { // line should be empty
throw new
IOException("Malformed line after content type: " + line);
}
}
else {
// Assume a default content type

contentType = "application/octet-stream";
}
// Now, finally, we read the content (end after reading the boundary)
if (filename == null) {
// This is a parameter
String value = readParameter(in, boundary);
parameters.put(name, value);
}
else {
// This is a file
readAndSaveFile(in, boundary, filename);
if (filename.equals("unknown")) {
files.put(name, new UploadedFile(null, null, null));
}
else {
files.put(name,
new UploadedFile(dir.toString(), filename, contentType));
}
}
return false; // there's more to read
}



protected String readParameter(MultipartInputStreamHandler in,
String boundary) throws IOException {
StringBuffer sbuf = new StringBuffer();
String line;
while ((line = in.readLine()) != null) {
if (line.startsWith(boundary)) break;
sbuf.append(line + "\r\n"); // add the \r\n in case there are many lines
}
if (sbuf.length() == 0) {
return null; // nothing read
}
sbuf.setLength(sbuf.length() - 2); // cut off the last line's \r\n
return sbuf.toString(); // no URL decoding needed
}



protected void readAndSaveFile(MultipartInputStreamHandler in,
String boundary,
String filename) throws IOException {
File f = new File(dir + File.separator + filename);
FileOutputStream fos = new FileOutputStream(f);
BufferedOutputStream out = new BufferedOutputStream(fos, 8 * 1024); // 8K
byte[] bbuf = new byte[8 * 1024]; // 8K
int result;
String line;
// ServletInputStream.readLine() has the annoying habit of
// adding a \r\n to the end of the last line.
// Since we want a byte-for-byte transfer, we have to cut those chars.
boolean rnflag = false;
while ((result = in.readLine(bbuf, 0, bbuf.length)) != -1) {
// Check for boundary
if (result > 2 && bbuf[0] == '-' && bbuf[1] == '-') { // quick pre-check
line = new String(bbuf, 0, result, "ISO-8859-1");
if (line.startsWith(boundary)) break;
}
// Are we supposed to write \r\n for the last iteration?
if (rnflag) {
out.write('\r'); out.write('\n');
rnflag = false;
}
// Write the buffer, postpone any ending \r\n
if (result >= 2 &&
bbuf[result - 2] == '\r' &&
bbuf[result - 1] == '\n') {
out.write(bbuf, 0, result - 2); // skip the last 2 chars
rnflag = true; // make a note to write them on the next iteration
}
else {
out.write(bbuf, 0, result);
}
}
out.flush();
out.close();
fos.close();
}



private String extractBoundary(String line) {
int index = line.indexOf("boundary=");
if (index == -1) {
return null;
}
String boundary = line.substring(index + 9); // 9 for "boundary="
// The real boundary is always preceded by an extra "--"
boundary = "--" + boundary;
return boundary;
}



private String[] extractDispositionInfo(String line) throws IOException {
// Return the line's data as an array: disposition, name, filename
String[] retval = new String[3];
// Convert the line to a lowercase string without the ending \r\n
// Keep the original line for error messages and for variable names.
String origline = line;
line = origline.toLowerCase();
// Get the content disposition, should be "form-data"
int start = line.indexOf("content-disposition: ");
int end = line.indexOf(";");
if (start == -1 || end == -1) {
throw new IOException("Content disposition corrupt: " + origline);
}
String disposition = line.substring(start + 21, end);
if (!disposition.equals("form-data")) {
throw new IOException("Invalid content disposition: " + disposition);
}
// Get the field name
start = line.indexOf("name=\"", end); // start at last semicolon
end = line.indexOf("\"", start + 7); // skip name=\"
if (start == -1 || end == -1) {
throw new IOException("Content disposition corrupt: " + origline);
}
String name = origline.substring(start + 6, end);
// Get the filename, if given
String filename = null;
start = line.indexOf("filename=\"", end + 2); // start after name
end = line.indexOf("\"", start + 10); // skip filename=\"
if (start != -1 && end != -1) { // note the !=
filename = origline.substring(start + 10, end);
// The filename may contain a full path. Cut to just the filename.
int slash =
Math.max(filename.lastIndexOf('/'), filename.lastIndexOf('\\'));
if (slash > -1) {
filename = filename.substring(slash + 1); // past last slash
}
if (filename.equals("")) filename = "unknown"; // sanity check
}
// Return a String array: disposition, name, filename
retval[0] = disposition;
retval[1] = name;
retval[2] = filename;
return retval;
}



private String extractContentType(String line) throws IOException {
String contentType = null;
// Convert the line to a lowercase string
String origline = line;
line = origline.toLowerCase();
// Get the content type, if any
if (line.startsWith("content-type")) {
int start = line.indexOf(" ");
if (start == -1) {
throw new IOException("Content type corrupt: " + origline);
}
contentType = line.substring(start + 1);
}
else if (line.length() != 0) { // no content type, so should be empty
throw new IOException("Malformed line after disposition: " + origline);
}
return contentType;
}
}



// A class to hold information about an uploaded file.
//
class UploadedFile {
private String dir;
private String filename;
private String type;
UploadedFile(String dir, String filename, String type) {
this.dir = dir;
this.filename = filename;
this.type = type;
}



public String getContentType() {
return type;
}



public String getFilesystemName() {
return filename;
}



public File getFile() {
if (dir == null || filename == null) {
return null;
}
else {
return new File(dir + File.separator + filename);
}
}
}



// A class to aid in reading multipart/form-data from a ServletInputStream.
// It keeps track of how many bytes have been read and detects when the
// Content-Length limit has been reached. This is necessary because some
// servlet engines are slow to notice the end of stream.
//
class MultipartInputStreamHandler {
ServletInputStream in;
String boundary;
int totalExpected;
int totalRead = 0;
byte[] buf = new byte[8 * 1024];
public MultipartInputStreamHandler(ServletInputStream in,String boundary,int totalExpected) {
this.in = in;
this.boundary = boundary;
this.totalExpected = totalExpected;
}



public String readLine() throws IOException {
StringBuffer sbuf = new StringBuffer();
int result;
String line;
do {
result = this.readLine(buf, 0, buf.length); // this.readLine() does +=
if (result != -1) {
sbuf.append(new String(buf, 0, result, "ISO-8859-1"));
}
} while (result == buf.length); // loop only if the buffer was filled
if (sbuf.length() == 0) {
return null; // nothing read, must be at the end of stream
}sbuf.setLength(sbuf.length() - 2); // cut off the trailing \r\n
return sbuf.toString();
}



public int readLine(byte b[], int off, int len) throws IOException {
if (totalRead >= totalExpected) {
return -1;
}
else {
int result = in.readLine(b, off, len);
if (result > 0) {
totalRead += result;
}
return result;
}
}
}
Feb 11 '08 #1
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1 Reply


BigDaddyLH
Expert 100+
P: 1,216
That's a lot of code! I'm too busy now to read that, but I remember file uploading only took a few lines of code when I used Common FileUpload: http://commons.apache.org/fileupload/
Feb 11 '08 #2

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