创建2个实体类：
Worker.java：
package com.entity;
public class Worker {
private String wid;
private String wname;
public String getWid() {
return wid;
}
public void setWid(String wid) {
this.wid = wid;
}
public String getWname() {
return wname;
}
public void setWname(String wname) {
this.wname = wname;
}
public Worker(String wid, String wname) {
super();
this.wid = wid;
this.wname = wname;
}
public Worker() {
super();
}
@Override
public String toString() {
return "Worker [wid=" + wid + ", wname=" + wname + "]";
}
}
Student.java：
package com.entity;
public class Student {
private Integer sid;
private String sname;
public Integer getSid() {
return sid;
}
public void setSid(Integer sid) {
this.sid = sid;
}
public String getSname() {
return sname;
}
public void setSname(String sname) {
this.sname = sname;
}
@Override
public String toString() {
return "Student [sid=" + sid + ", sname=" + sname + "]";
}
public Student(Integer sid, String sname) {
super();
this.sid = sid;
this.sname = sname;
}
public Student() {
super();
}
}
在同包下放入Student.hbm.xml 和Worker.hbm.xml2个配置
Student.hbm.xml:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="com.entity.Student" table="t_hibernate_student">
<id name="sid" type="java.lang.Integer" column="sid">
<!-- <generator class="assigned" /> -->
<!-- <generator class="identity" /> -->
<!-- <generator class="increment" /> -->
<!-- <generator class="sequence" > <param name="sequence_name">aaa</param>
</generator> -->
</id>
<property name="sname" type="java.lang.String" column="sname">
</property>
</class>
</hibernate-mapping>
Worker.hbm.xml:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="com.entity.Worker" table="t_hibernate_worker">
<id name="wid" type="java.lang.String" column="wid">
<generator class="com.id.MyTsGenerator" />
<!-- -->
<!-- <generator class="sequence" /> -->
<!-- <generator class="sequence" > <param name="sequence_name">aaa</param>
</generator> -->
</id>
<property name="wname" type="java.lang.String" column="wname">
</property>
</class>
</hibernate-mapping>
要用到的工具类：
SessionFacyoryUtils:
package com.util;
/**
* 仅在学习hibernate的工程中使用，进入spring的学习就用不到了，后面会有ssh替代
* 作用：
* 用来检测hibernate中的配置文件的准确性
* hibernate.cfg.xml
* *.hbm.xml
* @author xyls
*/
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
public class SessionFactoryUtils {
private static SessionFactory sessionFactory;
static {
Configuration cfg = new Configuration().configure("hibernate.cfg.xml");
sessionFactory = cfg.buildSessionFactory();
}
public static Session openSession() {
//从本地的线程中获取session会话，（第一次需要创建）
//第二次就能反复利用，节约性能
Session session = sessionFactory.getCurrentSession();
if(session == null) {
session = sessionFactory.openSession();
}
return session;
}
public static void closeSession() {
Session session = sessionFactory.getCurrentSession();
if(session != null && session.isOpen()) {
session.close();
}
}
public static void main(String[] args) {
Session session = SessionFactoryUtils.openSession();
session.beginTransaction();
System.out.println(session.isConnected());
SessionFactoryUtils.closeSession();
System.out.println(session.isConnected());
}
}
测试：
DemoDao：
package com.dao;
import org.hibernate.Session;
import org.hibernate.Transaction;
import com.entity.Student;
import com.entity.Worker;
import com.util.SessionFactoryUtils;
/**
* hibernate中的主键生成策略
* 1、人工控制
* 2、数据库控制
* 3、hibernate控制
* 4、自定义主键生成策略
* @author xyls
*
*/
public class DemoDao {
/**
* 新增学生
* @param stu
*/
public void add(Student stu) {
Session session = SessionFactoryUtils.openSession();
Transaction transation=session.beginTransaction();
session.save(stu);
transation.commit();
SessionFactoryUtils.closeSession();
}
/**
* 新增工人
* @param worker
*/
public void addWorker(Worker worker) {
Session session = SessionFactoryUtils.openSession();
Transaction transation=session.beginTransaction();
session.save(worker);
transation.commit();
SessionFactoryUtils.closeSession();
}
/**
*
* @param args
*/
public static void testStudent() {
DemoDao dao=new DemoDao();
Student stu=new Student();
stu.setSname("柳长歌");
stu.setSid(97);
dao.add(stu);
}
public static void main(String[] args) {
DemoDao dao=new DemoDao();
Worker worker=new Worker();
worker.setWname("220");
dao.addWorker(worker);
}
}
程序员自行控制：assigned（数据类型不限、保存前必须赋值）
数据库控制：identity(标识列/自动增长、 数字，无需赋值)
数据库控制：sequence（数字，无需赋值， 默认使hibernate_sequence这个序列，也可以通过sequence/sequence_name参数赋值）
hibernate控制:increment（数字，无需赋值）/uuid（32位的字符串，无需赋值，）
自定义主键生成器
建一个主键生成器类（实现org.hibernate.id.IdentifierGenerator接口）：
package com.id;
import java.io.Serializable;
import java.text.SimpleDateFormat;
import java.util.Date;
import org.hibernate.HibernateException;
import org.hibernate.engine.spi.SharedSessionContractImplementor;
import org.hibernate.id.IdentifierGenerator;
public class MyTsGenerator implements IdentifierGenerator {
@Override
public Serializable generate(SharedSessionContractImplementor session, Object object) throws HibernateException {
SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
return "book_order_"+sdf.format(new Date());
}
}
测试：
