Java Adapter 适配器模式（类适配器，对象适配器）优缺点对比

package com.bluemsun.classadapter;

public class Person {
  private int id;
  private String name;
  /**
   * person可以现在只能说英语
   */
  public void sayEnglish(){
    System.out.println("Person can say english!");
  }
  
  /**
   * 省略setter,getter.
   */
}

package com.bluemsun.classadapter;

/**
 * 目标要求person可以说英语,法语,日语.但是现在的person仅仅可以说英语
 * @author Administrator
 *
 */
public interface Target_Person {
  void sayEnglish();
  void sayFrench();
  void sayJapanese();
}

package com.bluemsun.classadapter;

/**
 * 类适配器,因为继承了Person,而Java中只能单继承,所以这个适配器只为person这一个类服务
 * 这个适配器就让person类在不修改源码的基础上能实现目标接口所指定的方法
 * @author Administrator
 *
 */
public class Adapter_Person extends Person implements Target_Person{

  @Override
  public void sayFrench() {
    System.out.println("Person can say French!");
  }

  @Override
  public void sayJapanese() {
    System.out.println("Person can say Japanese!");
  }
}

package com.bluemsun.classadapter;

public class Test {
  public static void main(String[] args) {
    Target_Person person = new Adapter_Person();
    
    person.sayEnglish();
    person.sayFrench();
    person.sayJapanese();
  }
}

package com.bluemsun.objectdapter;

import com.bluemsun.classadapter.Person;
import com.bluemsun.classadapter.Target_Person;

/**
 * 对象适配器,与类适配器不同的是:对象适配器可以适配多个源到目标
 * @author Administrator
 *
 */
public class Adapter_Person implements Target_Person{  //仅仅实现目标接口
  private Person person;
  
  //在构造函数中将Adaptee类Person传递进来
  public Adapter_Person(Person person){
    this.person = person;
  }

  //实现目标接口中的sayEnglish()--调用Adaptee中的sayEnglish()
  @Override
  public void sayEnglish() {
    this.person.sayEnglish();
  }

  //实现接口中的其它方法
  @Override
  public void sayFrench() {
    System.out.println("person can say French!");
  }

  @Override
  public void sayJapanese() {
    System.out.println("person can say Japanese!");
  }
}

package com.bluemsun.objectdapter;

import com.bluemsun.classadapter.Person;
import com.bluemsun.classadapter.Target_Person;

public class Test {
  public static void main(String[] args) {
    Target_Person person = new Adapter_Person(new Person());
    
    person.sayEnglish();
    person.sayFrench();
    person.sayJapanese();
  }
}