在工厂对象上调用创建方法，生成接口的某个实现的对象

通过这种方式，接口与实现分离

• 方法接口

  /**

  • 方法接口

  */ public interface Service { void method1(); void method2(); }

• 工厂方法接口

  /**

  • 工厂方法接口

  */ public interface ServiceFactory { Service getService(); }

• 方法实现

  /**

  • 实现类1

  */ public class Impl1 implements Service { public void method1(){System.out.println("Impl1 method1");} public void method2(){System.out.println("Impl1 method2");} }

  /**

  • 实现类2

  */ public class Impl2 implements Service{ public void method1(){System.out.println("Impl2 method1");} public void method2(){System.out.println("Impl2 method2");} }

• 工厂方法实现

  public class ImplFactory1 implements ServiceFactory { public Service getService(){ return new Impl1(); } }

  public class ImplFactory2 implements ServiceFactory{ public Service getService(){ return new Impl2(); } }

• 测试

  public class Test { public static void main(String[] args){ ServiceFactory sf1 = new ImplFactory1(); Service s1 = sf1.getService(); s1.method1(); s1.method2(); ServiceFactory sf2 = new ImplFactory2(); Service s2 = sf2.getService(); s2.method1(); s2.method2(); } }