Spring JDBC RowMapper usage for eager fetches

Question

The question is about the best practice usage for RowMapper in master/detail scenarios where we want to eagerly fetch details using spring jdbc.

Assume that we have

Answer 1

Easiest Method

You can simply use this library - SimpleFlatMapper has already solved that problem. All you need to do is create a ResultSetExtractor using the JdbcTemplateMapperFactory.

import org.simpleflatmapper.jdbc.spring.JdbcTemplateMapperFactory;

private final ResultSetExtractor> resultSetExtractor = 
    JdbcTemplateMapperFactory
        .newInstance()
        .addKeys("id") // the column name you expect the invoice id to be on
        .newResultSetExtractor(Invoice.class);

String query = "SELECT * FROM INVOICE inv JOIN INVOICE_LINE line on inv.id = line.invoice_id"

List results = jdbcTemplate.query(query, resultSetExtractor);

Add this dependancey to the pom.xml

    org.simpleflatmapper
    sfm-springjdbc
    8.2.1

Here is an article to refer - https://arnaudroger.github.io/blog/2017/06/13/jdbc-template-one-to-many.html

Here are examples for different usages - https://github.com/arnaudroger/SimpleFlatMapper/blob/master/sfm-springjdbc/src/test/java/org/simpleflatmapper/jdbc/spring/test/JdbcTemplateMapperFactoryTest.java