设计模式浅谈

来源：互联网发布：通常所说的linux是编辑：程序博客网时间：2024/05/01 01:12

1.单例模式
public class Singleton {
    privatestatic Singleton uniqueInstance = null;
    privateSingleton() {
      // Exists only to defeat instantiation.
    }
    publicstatic Singleton getInstance() {
      if (uniqueInstance == null) {
          uniqueInstance = new Singleton();
      }
      return uniqueInstance;
    }
    // Othermethods...
}

2.工厂模式
产品
public interface Work {
voiddoWork();
}
ConcreteProduct
public class StudentWork implements Work {

    publicvoid doWork() {
       System.out.println("学生做作业!");
    }

}
public class TeacherWork implements Work {

    publicvoid doWork() {
       System.out.println("老师审批作业!");
    }

}
生产者
public interface IWorkFactory {

WorkgetWork();
}
ConcreteCreator
public class StudentWorkFactory implements IWorkFactory {

    publicWork getWork() {
       return new StudentWork();
    }

}
public class TeacherWorkFactory implements IWorkFactory {

    publicWork getWork() {
       return new TeacherWork();
    }

}
Test
public class Test {

    publicstatic void main(String[] args) {
       IWorkFactory studentWorkFactory = new StudentWorkFactory();
       studentWorkFactory.getWork().doWork();

       IWorkFactory teacherWorkFactory = new TeacherWorkFactory();
       teacherWorkFactory.getWork().doWork();
    }

}

3.适配器模式

源的代码如下：

[c-sharp] view plaincopy

    publicclass Person {

       private String name;
       private String sex;
       private int age;

       public void speakJapanese(){
           System.out.println("I can speakJapanese!");
       }

       public void speakEnglish(){
           System.out.println("I can speak English!");
       }
       ...//以下省略成员变量的get和set方法
   }

目标接口的代码如下：

[c-sharp] view plaincopy

    publicinterface Job {

       public abstract void speakJapanese();
       public abstract void speakEnglish();
       public abstract void speakFrench();

   }

适配器的代码如下：

[c-sharp] view plaincopy

    publicclass Adapter extends Person implementsJob{

       public void speakFrench() {

       }

   }

好了，代码看完然后要做一些说明了，之前遗留的一个问题，为什么称其为类适配模式呢？很显然的，Adapter类继承了Person类，而在Java这种单继承的语言中也就意味着，他不可能再去继承其他的类了，这样也就是这个适配器只为Person这一个类服务。所以称其为类适配模式。

说完类的适配模式，我们要开始说第2种对象的适配器模式了。对象适配器模式是把“源”作为一个对象聚合到适配器类中。同样的话不多说，贴上代码：

源的代码以及目标代码同上，再次不再赘述。

仅贴出适配器代码：

[c-sharp] view plaincopy

    publicclass Adapter implements Job {

       Person person;

       public Adapter(Person person) {
           this.person = person;
       }

       public void speakEnglish() {
           person.speakEnglish();
       }

       public void speakJapanese() {
           person.speakJapanese();
       }

       //new add
       public void speakFrench() {

       }

   }

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