最近boss讓做項(xiàng)目，借機(jī)學(xué)習(xí)了一下Hibernate，小有收獲。
hiberante是對(duì)數(shù)據(jù)庫(kù)持久層訪(fǎng)問(wèn)的一種機(jī)制，hibernate的應(yīng)用可以使程序員將重點(diǎn)放到業(yè)務(wù)邏輯的實(shí)現(xiàn)上。hibernate的原理是將數(shù)據(jù)庫(kù)結(jié)構(gòu)封裝，使程序員可以像使用普通對(duì)象一樣調(diào)用數(shù)據(jù)庫(kù)的相關(guān)接口，從實(shí)現(xiàn)數(shù)據(jù)庫(kù)的相關(guān)操作。
由于Exadel基于eclipse集成了Hibernate，并且方便易用所以我選用
Exadel+Mysql
還需要hibernate3.jar
http://www.hibernate.org mysql-connector
http://dev.mysql.com/downloads/ 在Mysql中新建test數(shù)據(jù)庫(kù)（Mysql其實(shí)有個(gè)空的test數(shù)據(jù)庫(kù)），然后新建下面的Table
create table user (
id int(10) not null auto_increment primary key,
name varchar(20) not null,
password varchar(20) not null,
email varchar(50),
address varchar(100)
)type=innodb;
新建Java Project，將Mysql_Driver,Hibernate兩個(gè)user library添加到該工程的java build path中。
新建與數(shù)據(jù)表對(duì)應(yīng)的POJO類(lèi)：User和Contact
/**
*
*
*/
package com.user;
/**
* @author lzy
*
*/
public class User{
private Integer id;
private String name;
private String password;
private Contact contact;
/**
* @return Returns the id.
*/
public Integer getId() {
return id;
}
/**
* @param id The id to set.
*/
public void setId(Integer id) {
this.id = id;
}
/**
* @return Returns the name.
*/
public String getName() {
return name;
}
/**
* @param name The name to set.
*/
public void setName(String name) {
this.name = name;
}
/**
* @return Returns the password.
*/
public String getPassword() {
return password;
}
/**
* @param password The password to set.
*/
public void setPassword(String password) {
this.password = password;
}
/**
* @return Returns the contact.
*/
public Contact getContact() {
return contact;
}
/**
* @param contact The contact to set.
*/
public void setContact(Contact contact) {
this.contact = contact;
}
}
/**
*
*/
package com.user;
/**
* @author lzy
*
*/
public class Contact {
private String email;
private String address;
/**
* @return Returns the address.
*/
public String getAddress() {
return address;
}
/**
* @param address The address to set.
*/
public void setAddress(String address) {
this.address = address;
}
/**
* @return Returns the email.
*/
public String getEmail() {
return email;
}
/**
* @param email The email to set.
*/
public void setEmail(String email) {
this.email = email;
}
}
添加Hibernate支持，這時(shí)系統(tǒng)會(huì)要求輸入一些信息，按提示即可
完成后系統(tǒng)自動(dòng)生成hibernate.cfg.xml，User.hbm.xml
映射文件必須稍作修改。
hibernate.cfg.xml
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-configuration
PUBLIC "-//Hibernate/Hibernate Configuration DTD//EN"
"‘ target=_blank>http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory >
<!-- local connection properties -->
<property name="hibernate.connection.url">jdbc:mysql://localhost/test</property>
<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="hibernate.connection.username"></property>
<property name="hibernate.connection.password"></property>
<!-- property name="hibernate.connection.pool_size"></property -->
<!-- dialect for MySQL -->
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="hibernate.show_sql">True</property>
<property name="hibernate.transaction.factory_class">org.hibernate.transaction.JDBCTransactionFactory</property>
<mapping resource="User.hbm.xml"/>
</session-factory>
</hibernate-configuration>
User.hbm.xml
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd" >
<hibernate-mapping package="com.user">
<class
name="User"
table="user"
>
<id
name="Id"
type="integer"
column="id"
>
<generator class="native"/>
</id>
<property
name="Name"
column="name"
type="string"
not-null="true"
length="20"
/>
<property
name="Password"
column="password"
type="string"
not-null="true"
length="20"
/>
<component name="Contact" class="Contact">
<property
name="Email"
column="email"
type="string"
not-null="false"
length="50"
/>
<property
name="Address"
column="address"
type="string"
not-null="false"
length="100"
/>
</component>
</class>
</hibernate-mapping>
3.測(cè)試
添加一個(gè)測(cè)試類(lèi)：HibernateTest
package com.user;
import java.util.List;
import java.util.ListIterator;
import org.hibernate.*;
import org.hibernate.cfg.*;
public class HibernateTest {
public static void main(String[] args) throws HibernateException {
SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();
//
//testInsert(sessionFactory);
//
testQuery(sessionFactory);
sessionFactory.close();
}
public static void testInsert( SessionFactory sessionFactory )throws HibernateException {
Session session = sessionFactory.openSession();
Transaction tx= session.beginTransaction();
User user = new User();
Contact contact=new Contact();
contact.setEmail("email");
contact.setAddress("address");
user.setName("caterpillar");
user.setPassword("password");
user.setContact(contact);
session.save(user);
tx.commit();
session.close();
System.out.println("OK！");
}
public static void testQuery( SessionFactory sessionFactory )throws HibernateException {
Session session = sessionFactory.openSession();
Transaction tx= session.beginTransaction();
User user = new User();
Contact contact=new Contact();
Query query=session.createQuery("from User as user");
//query.setCharacter(1, ‘M‘);
List names =query.list();
for(ListIterator it=names.listIterator();it.hasNext();){
user= (User)it.next();
System.out.println("Id: " + user.getId());
System.out.println("name: " + user.getName());
System.out.println("password: " + user.getPassword());
if(user.getContact()!=null){
if(user.getContact().getEmail()!=null){
System.out.println("Email: " + user.getContact().getEmail());
}
if(user.getContact().getAddress()!=null){
System.out.println("Address: " + user.getContact().getAddress());
}
}
}
tx.commit();
session.close();
}
}
