bradleyross.j2ee.servlets

Class UploadServlet

java.lang.Object

javax.servlet.GenericServlet

javax.servlet.http.HttpServlet

bradleyross.j2ee.servlets.UploadServlet

All Implemented Interfaces:

Serializable, Servlet, ServletConfig

public class UploadServlet
extends HttpServlet

Start of servlet for testing techniques for uploads.

• RFC 2616 See section 19.5.1
• RFC 2388 - Returning Values From Forms: multipart/form-data
• RFC 1867 - Form-based File Upload in HTML

The specifications seem to say that the values on the headers may be tokens or quoted strings.

It may be necessary to expand this algorithm to handle additional transfer encoding types. The two mentioned on the web are base64 and quoted-printable.

MSDN lists the following types: 7bit, 8bit, binary, base64, quoted-printable, and X-token.

Author:

Bradley Ross

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	UploadServlet.Contents Contains information on the contents of a single part of a multipart form.
class	UploadServlet.Formatters Methods for formatting integers.
class	UploadServlet.ThisPage Contains information relating to a single HTTP request.

Field Summary

Fields

Modifier and Type	Field and Description
protected ServletConfig	config ServletConfig object for servlet.
protected static int	debugLevel Used to control amount of debugging output.
private static long	serialVersionUID Dummy id to satisfy serializable interface

Constructor Summary

Constructors

Constructor and Description
UploadServlet()

Method Summary

Methods

Modifier and Type	Method and Description
protected void	ender(UploadServlet.ThisPage thisPage) Perform common operations on the contents of the request packet to be carried out after running the main program.
String	extractBoundary(HttpServletRequest req) Extracts the value of the boundary string from the header.
void	init(ServletConfig configIn) Called when object for handling HTTP request is created.
void	loadByteArray(DatabaseProperties data, PreparedStatement stmt, UploadServlet.ThisPage thisPage, int position, String element) Utility method for moving the contents of one of the parts into a prepared statement as a string object.
void	loadByteArray(DatabaseProperties data, PreparedStatement stmt, UploadServlet.ThisPage thisPage, int position, String element, boolean convertFlag) Utility method for moving the contents of one of the parts into a prepared statement as a string object.
void	loadByteArray(DatabaseProperties data, PreparedStatement stmt, UploadServlet.ThisPage thisPage, int position, String element, boolean convertFlag, int SQLType) Utility method for moving the contents of one of the parts into a prepared statement as a string object.
protected void	processor(UploadServlet.ThisPage thisPage) This method generates the web page based on the contents of the request packet.
protected byte[]	readPart(ServletInputStream input, UploadServlet.ThisPage thisPage, String encoding) Obtain the byte array for this part of the request.
void	service(HttpServletRequest req, HttpServletResponse res) Process the call to the servlet.
protected void	starter(UploadServlet.ThisPage thisPage) Perform common operations on the contents of the request packet before running the main program.
protected String	stripEOL(String input) Strips end of line characters from a character string.

Methods inherited from class javax.servlet.http.HttpServlet

doDelete, doGet, doHead, doOptions, doPost, doPut, doTrace, getLastModified, service

Methods inherited from class javax.servlet.GenericServlet

destroy, getInitParameter, getInitParameterNames, getServletConfig, getServletContext, getServletInfo, getServletName, init, log, log

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

serialVersionUID

private static final long serialVersionUID

Dummy id to satisfy serializable interface

See Also:

Constant Field Values

debugLevel

protected static int debugLevel

Used to control amount of debugging output.

config

protected ServletConfig config

ServletConfig object for servlet.

Constructor Detail

UploadServlet

public UploadServlet()

Method Detail

init

public void init(ServletConfig configIn)
          throws ServletException

Called when object for handling HTTP request is created.

Specified by:

init in interface Servlet

Overrides:

init in class GenericServlet

Throws:

ServletException

service

public void service(HttpServletRequest req,
           HttpServletResponse res)
             throws IOException

Process the call to the servlet.

With regard to reading data from the request, a ServletInputStream object for binary data can be obtained by ServletRequest.getInputStream() or a BufferedReader can be obtained for character data by using ServletRequest.getReader().

With regard to writing data to the response a ServletOutputStream object for binary data can be obtained using ServletResponse.getOutputStream() while a PrintWriter object can be obtained using ServletResponse.getWriter().

The ByteArrayOutputStream class can be used as a means of collecting the bytes contained in the attached file.

It would be desirable to have tests for enctype and method.

Overrides:

service in class HttpServlet

Parameters:

req - Request object

res - Response object

Throws:

IOException

readPart

protected byte[] readPart(ServletInputStream input,
              UploadServlet.ThisPage thisPage,
              String encoding)
                   throws IOException

Obtain the byte array for this part of the request.

It may be necessary to modify this code to handle additional encoding types such as Base64.

Parameters:

input - Object from which data is read

thisPage - Object containing information for this request

Returns:

Byte array for this part of request

Throws:

IOException

stripEOL

protected String stripEOL(String input)

Strips end of line characters from a character string.

Parameters:

input - String to be processed

Returns:

String with EOL characters stripped off

extractBoundary

public String extractBoundary(HttpServletRequest req)

Extracts the value of the boundary string from the header.

Parameters:

req - Request object

Returns:

Boundary string

loadByteArray

public void loadByteArray(DatabaseProperties data,
                 PreparedStatement stmt,
                 UploadServlet.ThisPage thisPage,
                 int position,
                 String element,
                 boolean convertFlag,
                 int SQLType)
                   throws SQLException

Utility method for moving the contents of one of the parts into a prepared statement as a string object.

Parameters:

data - Data connection object.

stmt - Prepared statement

thisPage - Object representing this request

position - Position of the value in the prepared statement's argument list

element - Name of the part in the multi-part form

convertFlag - True means that value should be converted to upper case

SQLType - Type of SQL column (Types.CHAR or Types.VARCHAR)

Throws:

SQLException

loadByteArray

public void loadByteArray(DatabaseProperties data,
                 PreparedStatement stmt,
                 UploadServlet.ThisPage thisPage,
                 int position,
                 String element,
                 boolean convertFlag)
                   throws SQLException

Utility method for moving the contents of one of the parts into a prepared statement as a string object.

Parameters:

data - Data connection object.

stmt - Prepared statement

thisPage - Object representing this request

position - Position of the value in the prepared statement's argument list

element - Name of the part in the multi-part form

convertFlag - True means that value should be converted to upper case

Throws:

SQLException

loadByteArray

public void loadByteArray(DatabaseProperties data,
                 PreparedStatement stmt,
                 UploadServlet.ThisPage thisPage,
                 int position,
                 String element)
                   throws SQLException

Utility method for moving the contents of one of the parts into a prepared statement as a string object.

Parameters:

data - Data connection object.

stmt - Prepared statement

thisPage - Object representing this request

position - Position of the value in the prepared statement's argument list

element - Name of the part in the multi-part form

Throws:

SQLException

starter

protected void starter(UploadServlet.ThisPage thisPage)
                throws IOException

Perform common operations on the contents of the request packet before running the main program.

The intent is to override this method in a subclass that will then be subclassed to handle the servlets for the various web pages.

Parameters:

thisPage - Information on this HTTP request

Throws:

IOException

ender

protected void ender(UploadServlet.ThisPage thisPage)
              throws IOException

Perform common operations on the contents of the request packet to be carried out after running the main program.

Parameters:

thisPage - Information on this HTTP transaction

Throws:

IOException

processor

protected void processor(UploadServlet.ThisPage thisPage)
                  throws IOException

This method generates the web page based on the contents of the request packet.

This method will be overwritten to enable various actions to take place as the information is uploaded.

For the result of File requests, write the contents to a file.

I am having a problem with the loading of binary files.

Parameters:

thisPage - Information on this HTTP request

Throws:

IOException