I need to write a general function that handle queries.
the function get List<String> that hold parameters that is sent to the query.
how i implement that in hibernate.
to be more particular, if my query is:
select * from people where name=:name and family=:family
my list will contain
<"name","myname">
<"family","myfamily">
getHibernateTemplate() is most probably returning a org.springframework.orm.hibernate3.HibernateTemplate which is a Hibernate helper class in the spring framework. This is the code from the find method called therein:
public List find(final String queryString, final Object[] values) throws DataAccessException {
return (List) executeWithNativeSession(new HibernateCallback() {
public Object doInHibernate(Session session) throws HibernateException {
Query queryObject = session.createQuery(queryString);
prepareQuery(queryObject);
if (values != null) {
for (int i = 0; i < values.length; i++) {
queryObject.setParameter(i, values[i]);
}
}
return queryObject.list();
}
});
}
Have a look at the Hibernate Criteria API
This should get you started.
write query as:
String str="select * from people where name=? and family=?";
List<Object> queryParam=new ArrayList<Object>();
queryParam.add(name); //queryParam.add(yourList.get(0));
queryParam.add(family); //queryParam.add(yourList.get(1));
List<Object[]> List=getHibernateTemplate().find(str,queryParam.toArray());
If I read your question correctly, you want a generalized way to call a query that used named parameters, passing in a list that contains the the name/value pairs to bind.
This is pretty simple. I'm omitting the use of generics for clarity.
String query="select p from Person p where name=:name and family=:family";
String[] parameterArray = new String[] {"name", "myName", "family","myFamily"};
List parameters = Arrays.asList(parameterArray);
List results = callQuery(session, query, parameters);
public List callQuery(Session session, String query, List parameters) {
Query query = session.createQuery(query);
if (parameters != null && !parameters.isEmpty()) {
for (int i = 0; i < parameters.size(); i+=2) {
query.setParameter(parameters[i],parameters[i+1]);
}
}
return query.list();
}
An alternative is to use a Map, which makes iterating through the parameters to add them to the query a little cleaner; I also find it makes adding them to the collection to pass in to the generic method clearer, as well:
String query="select p from Person p where name=:name and family=:family";
Map<String,Object> parameters = new HashMap<String,Object>();
parameters.put("name","myName");
parameters.put("family,"myFamily");
List results = callQuery(session, query, parameters);
public List callQuery(Session session, String query, Map<String,Object> parameters) {
Query query = session.createQuery(query);
if (parameters != null && !parameters.isEmpty()) {
for (Map.Entry<String,Object> entry : parameters) {
query.setParameter(entry.getKey(),entry.getValue());
}
}
return query.list();
}
I'd also recommend looking into NamedQueries over the use of inline strings, as they let you include the queries in your mapping xml/annotations and add some query syntax validation.
You can use parameter list to inlcude in your query with 'IN' and 'setParameterList'
List<String> yourListString = new ArrayList<String>();
Query query = getSession().createQuery("select * from people where name in (:yourListString) and family in (:yourListString)"
query.setParameterList("yourListString ", yourListString);
query.executeUpdate();
