In my project I have read multiple tables with different queries and consolidate those results sets in flat files. How do I achieve that. I mean JdbcReader is directly taking 1 select query, how can I customize it.
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If JdbcCursorItemReader does not suit your needs, you are always free to implement a custom reader by implementing the ItemReader interface.
public interface ItemReader<T> {
T read() throws Exception, UnexpectedInputException, ParseException;
}
Just write a class that implements this interface and inject a jdbcTemplate to query multiple tables.
public Class MyCompositeJdbcReader implements ItemReader<ConsolidateResult>{
private JdbcTemplate jdbcTemplate;
public ConsolidateResult read()
throws Exception, UnexpectedInputException, ParseException{
ConsolidateResult cr = new ConsolidateResult();
String name= this.jdbcTemplate.queryForObject(
"select name from customer where id = ?",new Object[]{1}, String.class);
String phoneNumber= this.jdbcTemplate.queryForObject(
"select phone from customer_contact where custid = ?",
new Object[]{1},String.class);
cr.setName(name);
cr.setPhone(phoneNumber);
return cr;
}
}
I did not compile the code but I hope it gives an idea.
Serkan Arıkuşu
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I was using something similar to this solution.. but it never stop reading since there is never a null returned by this read method. – Cygnusx1 Nov 07 '12 at 19:55
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You may add something like this -> if (name==null) return null; – Serkan Arıkuşu Nov 08 '12 at 07:45
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1This method doesn't return list, what would I need to do if my query returns list ? – PAA Oct 16 '20 at 05:51