How to call PostgreSQL function in java?

Question

I have PostgreSQL+PostGIS.

I java i want to call this query:

SELECT num,id,mydata, asText(the_geom) FROM filedata

But get NullPointerException .
I think its couse i try to call function asText in this query and do it wrong. What i gonna do?

UPDATE

This is my code:

IndexedContainer container = createContainer("SELECT num,id,mydata, asText(the_geom) FROM filedata");

public IndexedContainer createContainer(String SQL) throws SQLException, ClassNotFoundException
{
    Class.forName("org.postgresql.Driver");
        Connection con= null;
      con =  DriverManager.getConnection("jdbc:postgresql://localhost:5432/postgis","postgres","123456");


    IndexedContainer container = new IndexedContainer();
    String sSQL = SQL;

    PreparedStatement ps = con.prepareStatement(sSQL);
 ////*****////
}

Answer 1

Most likely your problem is in the_geom - it is NOT table column (unless you did not follow any naming standards). If you are trying to build SQL in Java and pass a value from Java variable to SQL than you can use query parameters.
I suspect that you "forgot" that your SQL actually runs on SQL server where Java variables are not available.