Question on IntegerTypeHandler behaviour

[Asaf Mesika]

Hi,

I've noticed that there is an odd behavior (at least from my point of view) in IntegerTypeHandler class:

@Override
public Integer getNullableResult(ResultSet rs, String columnName)
    throws SQLException {
  return rs.getInt(columnName);
}

rs.getInt(columnName) returns 0 when the column value is null:

/**
 * Get the value of a column in the current row as a Java int.
 * 
 * @param columnIndex
 *            the first column is 1, the second is 2,...
 * 
 * @return the column value; 0 if SQL NULL
 * 
 * @exception SQLException
 *                if a database access error occurs
 */
public int getInt(int columnIndex) throws SQLException {

This is taken from com.mysql.jdbc.ResultSetImpl.

Why isn't the implementation for getNullableResult was something like:

int result = rs.getInt(columnName);

if (rs.wasNull()) {

   return null;

} else {

   return result;

}

This will make IntegerTypeHandler support Nullable Integer columns, and not return the number 0 instead of NULL.

[Iwao AVE!]

Hi Asaf,

That source looks old (< 3.5.0), so there should be a wasNull() check in BaseTypeHandler#getResult() method.

We moved the wasNull() check to IntegerTypeHandler in 3.5.0 [1].

In any version, IntegerTypeHandler does not return 0 if the column 'was null'.

[1] https://github.com/mybatis/mybatis-3/pull/1242

Regards,

Iwao

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