[Hsqldb-developers] Re: [Hsqldb-user] Writting objects to the database

[fredt <fr...@us...>]

You should try a test program which serializes your object outside HSQLDB to
see if you have successfully implemented the requirements of the
java.io.Serializable interface. A serializable object should not throw. You
can use the following test code:

        ByteArrayOutputStream bo = new ByteArrayOutputStream();

        try {
            ObjectOutputStream os = new ObjectOutputStream(bo);

            os.writeObject(yourobject);
        } catch (Exception e) {
            // problem with serialization - get the message from the
exception
        }

Fred Toussi

--------------------

Steve Ingersoll wrote:

I am running 1.7.0. I originaly had the object passed directly in but that
also had the problem. I was at one point getting a class cast exception for
a different reason which I thought was on the execute call but it turned out
to be on the statement insert call since it was not initialized at that
point. I fixed the problem but never went back and change it to pass the
object directly.

Thanks
Steve Ingersoll

--------------------

Please report which version of software you are using. Versions prior to
1.7.0 had problems with objects.

In your code you do not have to define  a new variable and cast your object
to Object. Every java object is an Object.

Fred Toussi

--------------------

Steve Ingersoll wrote:


I am getting a "Serialization failure: 40001" doing an insert command from
within a Java program.

I am trying to create a table that contains a java object. The create
statement I am using is:

                Statement stmnt = conn.createStatement();

                stmnt.executeUpdate(
                        "CREATE TABLE Users " +
                        "( username VARCHAR PRIMARY KEY," +
                        "  pwdRecord OBJECT )");

This seems to work ok but when I do the following is when I get the error:

        PreparedStatement insertStatement = conn.prepareStatement(
                                  "INSERT INTO Users (username, pwdRecord)
VALUES (?, ?)");


        insertStatement.setString(1, pwdEntry.getUsername());
        Object pwdRecord = (Object)pwdEntry;
        insertStatement.setObject(2, pwdRecord);
        //insertStatement.setNull(2,java.sql.Types.JAVA_OBJECT);
        System.out.println("Before execute");
        insertStatement.executeUpdate();
        System.out.println("After execute");
        } catch (SQLException ex) {
            System.out.println("Exception: " + ex);
            throw ex;
        }


If I comment out the setObject for item 2 and replace it with the setNull
then the call works.

The PwdEntry object is defined as:
public class PwdEntry
    implements java.io.Serializable {