Hibernate's Getting Started Crud

Package Com.test;import com.demo.user;import org.hibernate.hibernateexception;import org.hibernate.Session; Import Org.hibernate.sessionfactory;import Org.hibernate.transaction;import org.hibernate.cfg.Configuration; Import Org.junit.test;import java.util.arrays;import java.util.List;/** No hibernateutil gadget*/ Public classCrudtest {Private StaticSessionfactory sessionfactory;//The factory has only one build based on the configuration file .    Static{Configuration cfg=NewConfiguration (); //cfg.configure ();//default Auto-config hibernate.cfg.xml under src//Cfg.addresource ("Com/demo/user.hbm.xml");//Add a mapping file that has already been configured in the configuration)//Cfg.addclass (user.class);//go to the package in which the user class looks for a file with the name user and the suffix. Hbm.xmlCfg.configure ("Hibernate.cfg.xml");//reads the specified master profile (the location can also be specified without specifying, by default automatically finds the Cfg.xml under SRC)Sessionfactory = Cfg.buildsessionfactory ();//Generate session Factory} @Test Public voidTestsave () throws Exception {User u=NewUser (); U.setname ("BB"); U.setpassword ("1563"); U.settype ("Root"); Session ses= Sessionfactory.opensession ();//Open a new sessionTransaction ts = ses.begintransaction ();//Start Transaction----The object that created the transaction TS        Try{ses.save (u);//save data to table User1Ts.commit ();//Commit a transaction}Catch(Hibernateexception He) {he.printstacktrace (); System. out. println ("it's dead."); Ts.rollback ();//Rollback of a transaction}finally{ses.close ();            Sessionfactory.close (); System. out. println ("Insert Successful"); }} @Test Public voidTestget () throws Exception {Session session=sessionfactory.opensession (); Transaction TX=session.begintransaction (); User User= (User) session.Get(User.class,4);//get field 1 in the user tableSystem. out. println (user);//The tostring method has been rewritten [user:id=1,name=hoobey,password=456,type=admin]Tx.commit ();    Session.close (); } @Test Public voidTESTHQL () {Session session=sessionfactory.opensession (); Transaction TX=session.begintransaction (); String hql=NULL; //Execute Query//1. Simple Query        /*hql = "from User";*/        //2. Take the filter and sort from User as U--use alias as to omit        /*hql= "from User u where u.id = 1";*/        //3. Specify the SELECT clauseHQL ="Select U.id, u.name from User u";//querying multiple specified forexample returns the array output using array.tostring ()List List=session.createquery (HQL). List ();  for(Object obj:list) {if(Obj.getclass (). IsArray ()) {System. out. println (Arrays.tostring ((object[)) obj);//when the query returns an array}Else{System. out. println (obj);//Direct output When the query returns the type of the original property}            }          }        //---------------The second part of the study-----------------------------//1, aggregate function: Count (), Max (), Min (), AVG (), SUM ()//hql = "Select COUNT (*) from User";//The returned result is a long type.//hql = "Select min (id) from Employee";//The returned result is the type of the id attribute//Number result = (number) session.createquery (HQL). Uniqueresult ();//System.out.println (Result.getclass ());//System.out.println (Result); //2, group: GROUP By ... having//hql = "Select E.name,count (e.id) from the Employee e GROUP by E.name"; //hql = "Select E.name,count (e.id) from the Employee e GROUP by E.name have COUNT (e.id) >1"; //hql = "Select E.name,count (e.id) from the Employee e WHERE id<9 GROUP by E.name have COUNT (e.id) >1"; // ---        //hql = "Select E.name,count (e.id)" +//        //"from Employee E" +//        //"WHERE id<9" +//        //"GROUP by e.name" +//        //"having count (e.id) >1" +//        //"ORDER by Count (e.id) ASC"; // ---        //hql = "Select E.name,count (e.id) as C" +//        //"from Employee E" +//        //"WHERE id<9" +//        //"GROUP by e.name" +//        //"having count (e.id) >1" +//column aliases cannot be used in a HAVING clause//"ORDER by C ASC";//column aliases can be used in the By clause//3, Connection query/HQL is an object-oriented query//>> Internal connection (inner keyword can be omitted)//hql = "Select E.id,e.name,d.name from Employee e JOIN e.department D"; //hql = "Select E.id,e.name,d.name from Employee e INNER JOIN e.department d"; //>> LEFT OUTER join (outer keyword can be omitted)//hql = "Select E.id,e.name,d.name from Employee e left OUTER JOIN e.department D"; //>> right outer join (outer keyword can be omitted)//hql = "Select E.id,e.name,d.name from Employee e right JOIN e.department d"; //You can use the more convenient method//hql = "Select E.id,e.name,e.department.name from Employee e"; //4, using parameters when querying//>> method One: use '? ' Occupy position//hql = "from Employee e WHERE id between?" and? ";//List List = Session.createquery (HQL)//        //. Setparameter (0, 5)//set the parameter, and the index of the 1th parameter is 0. //. Setparameter (1,)//        //. List (); //>> Method Two: Use variable name//hql = "from Employee e WHERE id between:idmin and:idmax"; //List List = Session.createquery (HQL)//        //. Setparameter ("Idmax",//        //. Setparameter ("Idmin", 5)//        //. List (); //When the parameter is a collection, be sure to use Setparameterlist () to set the parameter value//hql = "from the Employee e WHERE ID in (: IDs)"; //List List = Session.createquery (HQL)//        //. Setparameterlist ("IDs", new object[] {1, 2, 3, 5, 8, +})//        //. List (); //5, using named Queries//query query = session.getnamedquery ("Querybyidrange"); //query.setparameter ("Idmin", 3); //query.setparameter ("Idmax", 10); //List List = Query.list (); //6,update with Delete, does not notify session cache//>> Update//int result = Session.createquery (////"UPDATE User e SET e.name=?" WHERE user_id = 2 ")////. Setparameter (0, "HGHG")////. executeupdate ();//returns the result of the int type, indicating how many rows were affected. //System.out.println ("result =" + result); //User user = (user) Session.get (user.class, 1);//System.out.println (User.getname ()); //>> Delete        /** int result = Session.createquery (//"DELETE from Employee e WHERE id>15")//. Executeupdate ();//return int type The result, which indicates how many rows were affected.         SYSTEM.OUT.PRINTLN ("result =" + result); */        //-----Execute the query and display the results// //List list = Session.createquery (HQL). List (); //For (Object obj:list) {//if (Obj.getclass (). IsArray ()) {//System.out.println (arrays.tostring ((object[)) obj); //} else {//System.out.println (obj); // }        // }Tx.commit ();    Session.close (); }}

Hibernate's Getting Started Crud