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Course Notes Table of Contents | Exercises
JDBC Short Course Index | Online Training Index

Help: Applet-Based Guestbook
Working Applet | Help
Solution

Help is available for each task, or you can go straight to the source code, which is one particular solution.

Task 1

Copy the odbc.datasource file from the previous exercise.

Task 2

Each connection to the CommentsServer creates an instance of CommentsConnection. It is your job to fillin the run method for this Thread. First determine which command came across. Valid commands are query and insert.

Use something like s.equals ("insert") as the if condition to check for the insert command.

Task 3

For insert mode:
  • Read the name, username, and comments from the ObjectInputStream.
  • Setup the Connection to the DriverManager.
  • Create a statement.
  • Populate/execute it.

Use ObjectInputStream.readObject() to read the strings from the socket's InputStream.

Ask the CommentsServer for the URL, username, and the password to use when getting your connection from the DriverManager.

Use Connection.prepareStatement to create a statement.

Use PreparedStatement.setString to place each parameter.

Remember that arguments to prepared statements, start at 1, not 0.

Use executeUpdate because the SQL statement to execute will update the database.

Task 4

For query mode:
  • Setup the Connection to the DriverManager.
  • Create a statement.
  • Execute it.
  • Read in ResultSet.

Ask the CommentsServer for the URL, username, and the password to use when getting your connection from the DriverManager.

Use Connection.createStatement to create statement.

Remember to use findColumn to determine which column is for which field when examining the ResultSet.

Task 5

Close each statement.

Both the PreparedStatement and the Statement need to be closed in their respective locations.

Task 6

Close the connection.



Copyright © 1997 MageLang Institute. All Rights Reserved
May-97 Copyright © 1996, 1997 Sun Microsystems Inc. All Rights Reserved