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This article is about how to use Hibernate code. The editor thinks it is very practical, so share it with you as a reference and follow the editor to have a look.

Hibernate is an upgraded version of JDBC that connects exclusively to the database. It is easier to use than JDBC and does not need to enter a lot of connection database code. There is no need to extract data from the database in a loop. The method to use is:

1. Create a new Java ordinary project

two。 Create user library to join the jar package in three places: two hibernate and a MYSQL driver

3. Create a hibernate profile, hibernate.cfg.xml

4. Establish the entity class user

5. Find the eg to the bottom of the hibernate file to find the user.hbm.xml mapping file, and copy to the same file as the mapping file.

6. Add the mapping file user.hbm.xml part to the hibernate.cfg.xml

7. Create a database, and then import entity mapping into the database using hibernate

Here is the code for the specific implementation:

/ / using hibernate, implement group by and sum and count Session sess = this.getSession (false); List list = null; if (sess! = null) {Criteria cri = sess.createCriteria (getModelClass ()); cri.add (Expression.allEq (props)); / / always count id ProjectionList projList = Projections.projectionList (); projList.add (Projections.sum (sum)); projList.add (Projections.groupProperty (group1)); projList.add (Projections.groupProperty (group2)) ProjList.add (Projections.count (count)); cri.setProjection (projList); list = cri.list ();} listlist = list = = null? New ArrayList (): list; return list; / / use hibernate to implement group by and sum and count List listByGroupSum = dao.getListByGroupSumCP (props); Iterator iter = listByGroupSum.iterator (); if (! iter.hasNext ()) {System.out.println ("No objects to display.");} while (iter.hasNext ()) {System.out.println ("New object"); Object [] obj = (Object []) iter.next () For (int I = 0; I < obj.length; iTunes +) {System.out.println (obj [I]);}} Thank you for reading! This is the end of this article on "how to use Hibernate code". I hope the above content can be of some help to you, so that you can learn more knowledge. if you think the article is good, you can share it for more people to see!

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