随笔档案(496)

Hibernate访问多个数据库的设计思路：利用 Hibernate中config = new Configuration().configure(configFile);可以加载不同数据库配置信息的原理，编写一个数据库操作类，再编写一个数据库管理程序[map]，将加载的数据库连接实例put早数据库管理程序中，具体实现见下面：

Hibernate访问多个数据库步骤一：hibernate配置文件

localhost.cfg.xml

< ?xml version="1.0" encoding="utf-8"?> 
< !DOCTYPE hibernate-configuration  
     PUBLIC "-//Hibernate/Hibernate Configuration DTD//EN"  
     "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd"> 
 
< hibernate-configuration> 
    < session-factory > 
 
  < !-- local connection properties --> 
  < property name="hibernate.connection.url">jdbc:mysql://localhost:3306/bookshop?zeroDateTimeBehavior=convertToNull< /property> 
  < property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver< /property> 
  < property name="hibernate.connection.username">root< /property> 
  < property name="hibernate.connection.password">12345678< /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>           
        < property name="hbm2ddl.auto">update< /property> 
 
     < mapping resource="org/jskyme/data/local/po/Shop.hbm.xml"/> 
    < /session-factory> 
< /hibernate-configuration> 

data_server.cfg.xml

< ?xml version="1.0" encoding="utf-8"?> 
 
< !DOCTYPE hibernate-configuration  
 
     PUBLIC "-//Hibernate/Hibernate Configuration DTD//EN"  
 
     "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd"> 
 
< hibernate-configuration> 
 
    < session-factory > 
 
  < !-- local connection properties --> 
 
  < property name="hibernate.connection.url">jdbc:mysql://192.168.0.10:3306/bookshop?zeroDateTimeBehavior=convertToNull< /property> 
 
  < property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver< /property> 
 
  < property name="hibernate.connection.username">root< /property> 
 
  < property name="hibernate.connection.password">12345678< /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>           
 
        < property name="hbm2ddl.auto">update< /property> 
 
     < mapping resource="org/jskyme/data/local/po/Shop.hbm.xml"/> 
 
    < /session-factory> 
 
< /hibernate-configuration> 

Hibernate访问多个数据库步骤二：数据库访问类：

数据库管理类：DataBaseManager

package org.jskyme.hibernate.util;  
 
import java.util.HashMap;  
 
public class DataBaseManager extends HashMap {  
 private static final long serialVersionUID = 6491666983237498097L;  
 private static DataBaseManager inst = new DataBaseManager();  
 
 public static DataBaseManager getInst() {  
  return inst;  
 }  
 
 public SessionManager get(Object key) {  
  return (SessionManager) super.get(key);  
 }  
 
 @Override  
 public Object put(Object key, Object value) {  
  return super.put(key, value);  
 }  
 
 public static void setInst(DataBaseManager inst) {  
   DataBaseManager.inst = inst;  
 }  
   
}  

Hibernate连接数据库操作类：

package org.jskyme.hibernate.util;  
 
import java.util.List;  
 
import org.hibernate.Criteria;  
import org.hibernate.Query;  
import org.hibernate.SQLQuery;  
import org.hibernate.Session;  
import org.hibernate.SessionFactory;  
import org.hibernate.Transaction;  
import org.hibernate.cfg.Configuration;  
 
public final class SessionManager {  
 private Configuration config;  
 
 private SessionFactory sessionFactory;  
 
 private Session session;  
 
 public Criteria createCriteria(Class persistentClass) {  
  return session.createCriteria(persistentClass);  
 }  
 
 private void buildSession() {  
   sessionFactory = config.buildSessionFactory();  
   session = sessionFactory.openSession();  
 }  
 
 public SessionManager(String configFile) {  
   config = new Configuration().configure(configFile);  
   buildSession();  
 }  
 
 public Session getSession() {  
  return session;  
 }  
 
 public void save(Object obj) {  
   Transaction tx = session.beginTransaction();  
   session.save(obj);  
   tx.commit();  
 }  
 
 public Object load(Class clas, Integer priId) {  
  return session.get(clas, priId);  
 }  
 
 public Query findbyhql(String hql) {  
  return session.createQuery(hql);  
 }  
 
 public List pageSizeByhql(String hql) {  
  return findbyhql(hql).list();  
 }  
 
 public SQLQuery findbysql(String sql) {  
  return session.createSQLQuery(sql);  
 }  
 
 public void update(Object obj) {  
   Transaction tx = session.beginTransaction();  
   session.saveOrUpdate(obj);  
   tx.commit();  
 }  
 public void delete(Class clas, Integer inte) {  
   session.delete(load(clas, inte));  
 }  
 
 public void delete(Object obj) {  
   session.delete(obj);  
 }  
 
 public void deletebyhql(String hql) {  
   Query query = session.createQuery(hql);  
   query.executeUpdate();  
 }  
 
 public Query createQuery(String hql) {  
  return session.createQuery(hql);  
 }  
 
}  

Hibernate访问多个数据库步骤三：测试类

1. package org.jskyme.data.test;
3. import junit.framework.TestCase;
5. import org.hibernate.Query;
6. import org.jskyme.hibernate.util.DataBaseManager;
7. import org.jskyme.hibernate.util.SessionManager;
9. public class DataBaseManagerTest extends TestCase {
10. DataBaseManager dbm = DataBaseManager.getInst();
12. public void testDatabase() {
13.    setDatabase();
14.    SessionManager tempSess = dbm.get("dataLocal");
15.    Query query = tempSess.createQuery("from   Shop");
16.    query.list();
17.   
18.    SessionManager tempSess27 = dbm.get("dateManage");
19.    Query query27 = tempSess27.createQuery("from Shop");
20.    query27.list();
21. }
23. private void setDatabase() {
24.    SessionManager dateManageLocal = new SessionManager("localhost.cfg.xml");
25.    SessionManager dateManage27 = new SessionManager("data_server.cfg.xml");
26.    dbm.put("dateManage", dateManage27);
27.    dbm.put("dataLocal", dateManageLocal);
29. }
30. }