14 结构性模式-适配器模式

1 适配器模式介绍

适配器模式(adapter pattern )的原始定义是：将类的接口转换为客户期望的另一个接口，适配器可以让不兼容的两个类一起协同工作。
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2 适配器模式原理

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3 适配器模式应用实例

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/**
 * SD卡接口
 **/
public interface SDCard {

    //读取SD卡
    String readSD();
    //写入SD卡
    void writeSD(String msg);
}

/**
 * SD卡实现类
 **/
public class SDCardImpl implements SDCard {

    @Override
    public String readSD() {
        String msg = "sd card reading data";
        return msg;
    }

    @Override
    public void writeSD(String msg) {
        System.out.println("sd card write data : " + msg);
    }
}

/**
 * TF卡接口
 **/
public interface TFCard {

    //读取TF卡
    String readTF();
    //写入TF卡
    void writeTF(String msg);
}

public class TFCardImpl implements TFCard {
    @Override
    public String readTF() {
        String msg = "tf card reading data";
        return msg;
    }

    @Override
    public void writeTF(String msg) {
        System.out.println("tf card write data : " + msg);
    }
}

/**
 * 适配器类(SD兼容TF)
 **/
public class SDAdapterTF  extends TFCardImpl implements SDCard{

    @Override
    public String readSD() {
        System.out.println("adapter read tf card");
        return readTF();
    }

    @Override
    public void writeSD(String msg) {
        System.out.println("adapter write tf card");
        writeTF(msg);
    }
}

/**
 * 电脑类
 **/
public class Computer {

    public String read(SDCard sdCard){
        String data = sdCard.readSD();
        return data;
    }
}

public class Client {

    public static void main(String[] args) {

        Computer computer = new Computer();
        SDCard sdCard = new SDCardImpl();
        String read = computer.read(sdCard);
        System.out.println(read);

        System.out.println("=====================");
        SDAdapterTF adapterTF = new SDAdapterTF();
        System.out.println(computer.read(adapterTF));
    }
}

4. 对象适配器模式

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/**
 * 对象适配器-组合形式
 **/
public class SDAdapterTF2  implements SDCard {

    private TFCard tfCard;

    public SDAdapterTF2(TFCard tfCard) {
        this.tfCard = tfCard;
    }

    @Override
    public String readSD() {
        System.out.println("adapter read tf card");
        return tfCard.readTF();
    }

    @Override
    public void writeSD(String msg) {
        System.out.println("adapter write tf card");
        tfCard.writeTF(msg);
    }
}

public class Client {

    public static void main(String[] args) {

        Computer computer = new Computer();
        SDCard sdCard = new SDCardImpl();
        System.out.println(computer.read(sdCard));

        System.out.println("=======================");
        TFCard tfCard = new TFCardImpl();

        SDAdapterTF2 adapterTF2 = new SDAdapterTF2(tfCard);
        System.out.println(computer.read(adapterTF2));
    }
}