I am working on standardizing a legacy code base and new development to both use EntityManager for persistence. In order to succeed, I need to provide the ability to break out into native SQL and process results manually. JPA EntityManager almost provides this functionality through:
em.createNativeQuery("select ... from my_table where ...")
But what I am missing is the ability to do Spring style RowMappers. I can see that there are a few mechanisms that are close. I can of-course map entities using annotations, xml and so on but I need to put code into the processing of each row in the result set so this is not an option. I can see that I can pass in SQLResultSetMapping, but as best as I can understand, this supports again only meta data mapping. Ideally what I need is the following:
em.createNativeQuery("select ... from my_table where ...",
new RowMapper {
public Object mapRow(ResultSet rs, int rowNum) throws SQLException {
MyObject o = new MyObject();
o.setMyCustomProperty( rs.get...() );
//...
return b;
}
}
);
Does the equivalent to the above exist? Can I construct a SQLResultSetMapping which takes full control of the mapping like the above. If not, can I at least get the data source underlying the EM so that I can wrap it using JdbcTemplate?
DataSource ds = em.getDataSource();
JdbcTemplate t = new JdbcTemplate(ds);
// use RowMapper
