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POHow to transform DBUtils resultset into JavaBeans composited from more domain objects?
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  1. POHow to transform DBUtils resultset into JavaBeans composited from more domain objects?
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    copied!<p>I am creating MVC web application in Spring Framework and I need to transform rows from Apache DBUtils resultset into JavaBeans that is composed from nested objects.</p> <p>With respect to a very few examples I found I created this RowProcessor implementation.</p> <pre><code>public class MonthOrderCountHandler extends BasicRowProcessor { @Override public Object toBean(ResultSet rs, Class type) throws SQLException { // Year Year year = new Year(); year.setYearNo(rs.getInt("yearNo")); year.setYear4(rs.getString("year4")); year.setYear2(rs.getString("year2")); // Quarter Quarter quarter = new Quarter(); quarter.setQuarter(rs.getInt("quarter")); // Month Month m = new Month(); m.setYear(year); m.setQuarter(quarter); m.setMonthAbbreviation(rs.getString("monthAbbreviation")); m.setMonthName(rs.getString("monthName")); m.setMonthNo(rs.getInt("monthNo")); // Final bean MonthOrderCount result = new MonthOrderCount(); result.setMonth(m); result.setOrderCount(rs.getInt("orderCount")); return result; } } </code></pre> <p><strong>Question:</strong> I would like to know know how to use this row processor in my DAO object and if this implementation is correct?</p> <hr> <p>Commonly I transform rows into JavaBeans in this way:</p> <pre><code>ResultSetHandler&lt;List&lt;MonthOrderCount&gt;&gt; listUrlHandler = new BeanListHandler&lt;&gt;(MonthOrderCount.class); </code></pre> <p>But in my situation first Ineed to create nested objects and then create a final JavaBean, so I assume I need custom row processor.</p> <hr> <p>Structure of my domain objects is:</p> <p>MonthOrderCount class:</p> <pre><code>public class MonthOrderCount { private Month month; private int orderCount; } </code></pre> <p>Month class:</p> <pre><code>public class Month { private Quarter quarter; private Year year; private int monthNo; private String monthName; private String monthAbbreviation; } </code></pre> <p>Quarter class:</p> <pre><code>public class Quarter { private int quarter; private String abbreviation; } </code></pre> <p>Year class:</p> <pre><code>public class Year { private int yearNo; private String year2; private String year4; } </code></pre> <p><strong>EDIT:</strong> I am asking because my result looks like this. orderCount variable is properly filled but month is null in all instances. Buw what is the most weird for me - toBean() method is never called.</p> <blockquote> <p>2013-03-10 17:09:46 INFO ChartDataService:29 - [MonthOrderCount{month=null, orderCount=1863}, MonthOrderCount{month=null, orderCount=2262}, MonthOrderCount{month=null, orderCount=2531}, MonthOrderCount{month=null, orderCount=2379}, MonthOrderCount{month=null, orderCount=2106}, MonthOrderCount{month=null, orderCount=1498}, MonthOrderCount{month=null, orderCount=1300}, MonthOrderCount{month=null, orderCount=1578}, MonthOrderCount{month=null, orderCount=2385}, MonthOrderCount{month=null, orderCount=2991}, MonthOrderCount{month=null, orderCount=2219}, MonthOrderCount{month=null, orderCount=1943}, MonthOrderCount{month=null, orderCount=264}]</p> </blockquote>
 

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