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Singleton.java£º
package com.xfimti.sigleton;
public class Singleton
{
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 private static Singleton singleton = new Singleton();
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 private static Singleton mySingleton = null;
 
 private Singleton()
 {
 }
 
 /*µÚÒ»ÖÖ·½Ê½¡£*/
 public static Singleton getSingletonInstance()
 {
  return singleton;
 }
 
 /*µÚ¶þÖÖ·½Ê½¡£*/
 public static Singleton getInstance()
 {
  if(mySingleton == null)
  {
   mySingleton = new Singleton();
  }
  return singleton;
 }
}
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Dao.java
package com.xfimti.factory;
public interface Dao
{
 public void save();
}
DaoImpl4Mysql.java
package com.xfimti.factory;
public class DaoImpl4Mysql implements Dao
{
 public void save()
 {
  System.out.println("save for dao...");
 }
}
(¾²Ì¬¹¤³§)StaticFactory.java
package com.xfimti.factory;
/**¾²Ì¬¹¤³§»ò¼òµ¥¹¤³§*/
public class StaticFactory
{
 public static Dao getDao(String type)
 {
  if(type.equals("mysql"))
  {
   return new DaoImpl4Mysql();
  }
  return null;
 }
}
²âÊÔÀࣺMain.java
package com.xfimti.factory;
public class Main
{
 public static void main(String[] args)
 {
  /*ʹÓþ²Ì¬¹¤³§ ¡£*/
//  Dao dao = StaticFactory.getDao("mysql");
//  dao.save();
  
  Dao dao = new DaoFactoryMethod().getDao("mysql");
  dao.save();
 }
}
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DaoFactoryMethod.java
package com.xfimti.factory;
/*ʵÀý¹¤³§·½·¨¡£*/
public class DaoFactoryMethod
{
 public Dao getDao(String type)
 {
  if(type.equals("mysql"))
  {
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