Query string - Depending on passed values

[jonnybecker]

Hi,

I've got a function like this:

public List getList(String a, String a, Date c) {
		String query = "from de.model.sap.Table1 t1 where t1.col1 = ? and t1.col2 = ? and t1.col3 = ?";
	String obj[] = new String[3];
	obj[0] = a;
        obj[0] = b;
        obj[0] = c;
	return this.getHibernateTemplate().find(query, obj);
}

Now I want my string a little bit more dynamic. If a passed value is null, it should't be considered in the query.

For example, if String a is null the query string only be:

"from de.model.sap.Table1 t1 where t1.col2 = ? and t1.col3 = ?"


Is there a way (or whatever) to achieve this, NOT creating this query/string by hand in a way like this:

if(a=! null || b!= null || c != null){
	query += " WHERE ";
}
...

Thanks
Jonny

[lightc]

Use the criteria query api instead:

final Criteria criteria = session.createCriteria(Table1.class);
if (a != null) criteria.add(Restrictions.eq("col1", a);
if (b != null) criteria.add(Restrictions.eq("col2", b);
if (c != null) criteria.add(Restrictions.eq("col3", c);
final List list = criteria.list();

String concatenated queries are evil!

:evil:

[Costin Leau]

Null values are a special case - you have to add an if and create the query based on these values:

if (a != null)
   query += " t1.col1 = ? ";
else
   query += " t1.col1  is null ";