Hibernate Framework Description:
ORM Concept (very important)
The O,object object. r,relation relationship. m,mapping Mapping
ORM: Object Relational Mapping!
ORM, what's the problem?
Storage: Whether the object's data can be saved directly into the database
Get: Whether you can get an object directly from the database
To achieve the above two points, there must be a mapping
Summary: Relationship between Hibernate and Orm: Hibernate is the implementation of ORM
How to build a hibernate development environment, development steps:
(1) Download source code: Version number hibernate-distribution-3.6.0.final
(2) Introduction of JAR file: Hibernate3.jar core +required must be introduced (6) +jsp folder +mysql driver
(3) Mapping of objects and objects
Employee.java Object
Mapping of Employee.hbm.xml objects (typically we use the hbm.xml end, which is to differentiate the Hibernate mapping file)
(4) Src/hibernate.cfg.xml (the name of this file must be written in this way)
1.employee.java
Package Cn.itcast.hello;import Java.util.date;public class Employee {private int id;private String empname;private Date W orkdate;public int getId () {return ID;} public void setId (int id) {this.id = ID;} Public String Getempname () {return empname;} public void Setempname (String empname) {this.empname = EmpName;} Public Date Getworkdate () {return workdate;} public void Setworkdate (Date workdate) {this.workdate = workdate;}}
2.employee.hbm.xml file
Primarily includes primary key mappings and non-primary key mappings
<?XML version= "1.0"? ><! DOCTYPE hibernate-mapping Public "-//hibernate/hibernate mapping DTD 3.0//en" "http://www.hibernate.org/dtd/ Hibernate-mapping-3.0.dtd ">
3.hibernate.cfg.xml file
(1) Configuration of the database connection. If you don't understand, you can go to Hibernate source code/project/etc/hibernate.properties find copy and paste
(2) Other configuration contains dialect and is not the configuration information of their own initiative to build the table
(3) The introduction of the mapping file. <mapping resource= "folder for configuration Files"/>
<! DOCTYPE hibernate-configuration Public "-//hibernate/hibernate configuration DTD 3.0//en" "Http://www.hibern Ate.org/dtd/hibernate-configuration-3.0.dtd ">4. Test class ApptestTo write the steps:
(1). Gets the management class object that loads the configuration file. (2). Load the configuration file. (3). Create a session factory object. (4). Create a session (which represents a conversation.) The session connected to the database). (5). Turn on the transaction. (6). Operation with the database . (7). Commit the transaction. (8). Close the resource.
Package Cn.itcast.hello;import Java.util.date;import Org.hibernate.sessionfactory;import org.hibernate.Transaction ; Import Org.hibernate.cfg.configuration;import Org.hibernate.classic.session;import Org.junit.test;public class apptest {@Testpublic void Test () {Employee emp=new employee (); Emp.setempname ("Li Weikang"); Emp.setworkdate (new Date ());//1. Gets the management class object that loads the configuration file. Configuration config=new configuration ();//2. load config file config.configure ();// The default load is Hiberate.xml file//3 under the SRC folder. Create session Factory object Sessionfactory factory = Config.buildsessionfactory ();//4. Create Session ( Represents a dialogue. Session with database connection) Session session = Factory.opensession ();//5. Open transaction Transaction tx = Session.begintransaction ();//6. Operation with Database Session.save (EMP);//7. Commit Transaction Tx.commit ();//8. Close Resource Session.close ();}}
Execution results can find a table with one employee in the database and a record
Hibernate Getting Started case