The AS400LobServer application demonstrates how to access DB2/400 
LOBs (BLOBs and CLOBs) using the AS/400 Toolbox for Java.  There are 
three requirements for successful installation and execution of the application:

1.  A client workstation with a Java 2 JRE or SDK installed must be used. The 
application uses the JDBC 2.0 scrollable cursor support which requires a 
Java 2 JRE or SDK.  

2.  A recent (September '99 or later modified date) version of the jt400.jar or 
jt400.zip needs to be in the workstation's classpath.
 
3.  A database must be created on the AS/400 which contains one or more 
LOB (BLOB or CLOB) fields. The actual BLOBs and CLOBs can be named anything
you wish. But, a traditional character or varchar field with a specific
naming convention MUST be added for each BLOB or CLOB you wish to access 
with this application.  For instance, if you already have a BLOB field 
called 'PHOTO' in the database, please add a character field specifically 
named 'PHOTO_ID'. This field will be used to store the original name and 
extension of the LOB file when the 'Update Lob' button is clicked. Likewise, 
the 'Retrieve Lob' option will return the information stored in that field, 
along with the LOB itself, so that it is a usable object when it is dropped 
to your PC file system from DB2/400.
   If a field having the naming convention ' <name of BLOB field>  + _ID'
is not added to your database for every LOB that you wish to access,  the 
application will return a message stating that it doesn't exist. Adding the
additional field(s) will solve the problem.  In summary, you can name the 
actual CLOB or BLOB fields anything you wish. But, for this particular 
application to work properly, the additional character fields  with the
aforementioned naming convention must be added for LOB identification purposes 
since the files are being transferred back and forth between a PC file system 
(which contains the file name and extension type) and a database (which
loses the file name and extension type if it is not stored elsewhere).  
   The following is an example of the interactive SQL commands that may be issued 
via an AS/400 5250 session to create a minimal database that may be 
used in conjunction with this AS400LobServer application:
  STRSQL
  CREATE COLLECTION PHOTOS
  CREATE TABLE PHOTOS/CUSTOMER (CSTNBR INT NOT NULL, PHOTO BLOB ( 1M), PHOTO_ID CHAR( 100)) 
  INSERT INTO PHOTOS/CUSTOMER (CSTNBR) VALUES(1)

Next, extract the AS400LobServer.zip application to a root drive on your workstation, 
choosing to preserve the directory structure during the extraction process.

Then, perform the following DOS commands to run the application: 
    <logical drive partition containing the extracted application>:
    cd \
    cd Blob   
    java SignOnScreen

Use the 'UPDATE LOB' button to insert an image file into the CUSTOMER database from 
your PC file system. If the image update is successful, you can then click the
'DISPLAY GIF/JPG' button to view the image that was just inserted into the database. 
The 'RETRIEVE LOB' button is used to transfer a Lob from DB2/400 to your PC file 
system for viewing at a later time. 
  
All of the class, source, and resource files for this application are stored within the
'Blob' folder. All of the source code which actually manipulates a BLOB/CLOB is contained 
in the DisplayBlob and LobServer .java files. The other classes are simply used to build
and display some of the GUI frames used in the application.

The SignOnScreen.gif, LobHandler.gif, and DisplayBlob.gif are screenshots of the frames
used in the application with example input data shown in the text fields.