Hibernate初级入门

一、Hibernate扮演的是什么角色

Hibernate在javaee中的三层结构中扮演的是DAO层框架

使用Hibernate框架简化了JDBC复杂的代码，是一种开源的轻量级的框架

二、如何搭建Hibernate的环境

1.导入包：

记得build path哟！！！！

三、ORM

Object  Reational  Mapping—-对象关系模型

在web阶段学习的javabean,现在叫实体类;

一个实体类对应数据库中一个表，，实体类中的属性对应数据库表字段

比如：

private String userName;<—————>t_userName(这个我们要通过映射文件来创建)

四、如何写一个实体类的映射文件：

项目结构：

Customer:客户  LinkMan：联系人

场景：一个客户对应多个联系，一个联系人对应一个客户

package cn.cq.enty;

import java.util.HashSet;

import java.util.Set;

public class Customer {


//客户id


private Integer cid;


//客户名称


private String custName;


//客户级别


private String custLevel;


//客户来源


private String custSource;


//联系电话


private String custPhone;


//手机


private String custMobile;


//客户实体类中表示对个联系人


private Set<LinkMan> setLinkMan = new HashSet<LinkMan>();





public Set<LinkMan> getSetLinkMan() {


return setLinkMan;


}


public void setSetLinkMan(Set<LinkMan> setLinkMan) {


this.setLinkMan = setLinkMan;


}


public Customer() {


super();





}


public Customer(Integer cid, String custName, String custLevel,


String custSource, String custPhone, String custMobile) {


super();


this.cid = cid;


this.custName = custName;


this.custLevel = custLevel;


this.custSource = custSource;


this.custPhone = custPhone;


this.custMobile = custMobile;


}


public Integer getCid() {


return cid;


}


public void setCid(Integer cid) {


this.cid = cid;


}


public String getCustName() {


return custName;


}


public void setCustName(String custName) {


this.custName = custName;


}


public String getCustLevel() {


return custLevel;


}


public void setCustLevel(String custLevel) {


this.custLevel = custLevel;


}


public String getCustSource() {


return custSource;


}


public void setCustSource(String custSource) {


this.custSource = custSource;


}


public String getCustPhone() {


return custPhone;


}


public void setCustPhone(String custPhone) {


this.custPhone = custPhone;


}


public String getCustMobile() {


return custMobile;


}


public void setCustMobile(String custMobile) {


this.custMobile = custMobile;


}

}

package cn.cq.enty;

public class LinkMan {

private Integer lkm_id; // 联系人编号(主键)
private String lkm_name;// 联系人姓名
private String lkm_gender;// 联系人性别
private String lkm_phone;// 联系人办公电话
//表示一个联系人对应一个客户
private Customer customer;

public Customer getCustomer() {

return customer;
}
public void setCustomer(Customer customer) {

this.customer = customer;
}
public LinkMan() {

super();

}
public LinkMan(Integer lkm_id, String lkm_name, String lkm_gender,
String lkm_phone) {

super();
this.lkm_id = lkm_id;
this.lkm_name = lkm_name;
this.lkm_gender = lkm_gender;
this.lkm_phone = lkm_phone;
}
public Integer getLkm_id() {

return lkm_id;
}
public void setLkm_id(Integer lkm_id) {

this.lkm_id = lkm_id;
}
public String getLkm_name() {

return lkm_name;
}
public void setLkm_name(String lkm_name) {

this.lkm_name = lkm_name;
}
public String getLkm_gender() {

return lkm_gender;
}
public void setLkm_gender(String lkm_gender) {

this.lkm_gender = lkm_gender;
}
public String getLkm_phone() {

return lkm_phone;
}
public void setLkm_phone(String lkm_phone) {

this.lkm_phone = lkm_phone;
}


}

Customer.hbm.xml(放在同一个包下）

<?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>
   <!– 配置类和表的对应关系
    Class标签：
    name属性：实体类全路径
    table属性：数据库中表的名称
   
    –>
    <class name=”cn.cq.enty.Customer” table=”t_customer”>
    <!– 
    hibernate要求实体类有一个属性唯一值
    要求表字段作为唯一值
    –>
    <!– 
    配置实体类id和表中的id的关系
    name属性：表示实体类中id属性名称
    column属性：表示数据中表字段
    –>
    <id name=”cid” column=”cid”>
    <!– 设置数据中id字段增长策略
    native:表示id自动增长
    –>
    <generator class=”native”></generator>
    </id>
   
    <!– 
    配置实体类属性和表字段对应关系
    name属性：实体类属性名称
    column属性：表字段名称
    –>
    <property name=”custName” column=”custName”></property>
    <property name=”custLevel” column=”custLevel”></property>
    <property name=”custSource” column=”custSource”></property>
    <property name=”custPhone” column=”custPhone”></property>
    <property name=”custMobile” column=”custMobile”></property>
    <!– 使用set标签表示所有联系人
    set标签name属性：客户实体类中set集合的名称
    Column：表示外键
    –>
    <set name=”setLinkMan” cascade=”save-update,delete” inverse=”true”>
    <key column=”cid”></key>
    <!– 客户所有的联系人
    class：写联系人实体类的全路径
    –>
    <one-to-many class=”cn.cq.enty.LinkMan”/>
    </set>
    </class>
   </hibernate-mapping>

LinkMan.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=”cn.cq.enty.LinkMan” table=”t_linkMan”>
    <id name=”lkm_id” column=”lkm_id”>
    <generator class=”native”></generator>
    </id>
    <property name=”lkm_name” column=”lkm_name”></property>
    <property name=”lkm_gender” column=”lkm_gender”></property>
    <property name=”lkm_phone” column=”lkm_phone”></property>
    <many-to-one name=”customer” column=”cid” class=”cn.cq.enty.Customer”></many-to-one>
   
    </class>
   </hibernate-mapping>

五。创建核心配置文件：

要求：放到src目录下

名称必须写成：hibernate.cfg.xml

<?xml version=”1.0″ encoding=”UTF-8″?>
<!DOCTYPE hibernate-configuration PUBLIC
“-//Hibernate/Hibernate Configuration DTD 3.0//EN”
“http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd”>
<hibernate-configuration>

<!–  数据库的基本信息–>
<session-factory>
<property name=”hibernate.connection.driver_class”>com.mysql.jdbc.Driver</property>
<property name=”hibernate.connection.url”>jdbc:mysql:///hibernate03</property>
<property name=”hibernate.connection.username”>root</property>
<property name=”hibernate.connection.password”>bdqn</property>

<!–mysql数据库的方言–>
<property name=”hibernate.dialect”>org.hibernate.dialect.MySQLDialect</property>

<!–输出底层sql语句–>
<property name=”hibernate.format_sql”>true</property>

<!–输出底层sql语句–>
<property name=”hibernate.show_sql”>true</property>

<!–hibenate绑创建表

update:如果有表，更新，如果没得表，创建表

–>
<property name=”hibernate.hbm2ddl.auto”>update</property>

<!–和本地session绑定–>
<property name=”hibernate.current_session_context_class”>thread</property>

<!–把映射文件放到核心配置文件中–>
<mapping resource=”cn/cq/enty/Customer.hbm.xml”/>
<mapping resource=”cn/cq/enty/LinkMan.hbm.xml”/>

</session-factory>
</hibernate-configuration>

六：HibernateUtils:

package cn.cq.test;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;

public class HibernateUtils {

private static Configuration cfg = null;
private static SessionFactory sessionFactory = null;

static {

cfg = new Configuration().configure();
sessionFactory = cfg.buildSessionFactory();
}

public static SessionFactory getSessionFactory(){

return sessionFactory;
}

public static Session getSession(){

return sessionFactory.getCurrentSession();
}

}

七，实现CURD操作：

package cn.cq.test;

import org.hibernate.Session;
import org.hibernate.Transaction;
import org.junit.Test;

import cn.itcast.enty.Customer;
import cn.itcast.enty.LinkMan;

public class HibernateOneToMang {

@Test
public void add(){

Session session = null;
Transaction tx = null;
try {

session = HibernateUtils.getSession();
tx = session.beginTransaction();
Customer cus = new Customer();
cus.setCustName(“baidu”);
cus.setCustLevel(“vip”);
cus.setCustSource(“network”);
cus.setCustPhone(“111”);
cus.setCustMobile(“999”);

LinkMan linkMan = new LinkMan();
linkMan.setLkm_name(“kevin”);
linkMan.setLkm_gender(“nan”);
linkMan.setLkm_phone(“3333”);

cus.getSetLinkMan().add(linkMan);

session.save(cus);

tx.commit();
} catch (Exception e) {

tx.rollback();
}finally{


}
}

@Test
public void delete(){

Session session = null;
Transaction tx = null;
try {

session = HibernateUtils.getSession();
tx = session.beginTransaction();
Customer cus = session.get(Customer.class, 1);
session.delete(cus);
tx.commit();
} catch (Exception e) {

tx.rollback();
}finally{


}
}

@Test
public void update(){

Session session = null;
Transaction tx = null;
try {

session = HibernateUtils.getSession();
tx = session.beginTransaction();
Customer qq = session.get(Customer.class,3);

LinkMan cidy = session.get(LinkMan.class, 3);

qq.getSetLinkMan().add(cidy);

cidy.setCustomer(qq);

tx.commit();
} catch (Exception e) {

tx.rollback();
}finally{


}

}
}