依賴注入之接口注入

書本上說：這種接口注入的方式須要調用者必須實現一個指定的接口，這種方式使用比較少，通常不推薦使用

一、項目截圖

二、打印機接口類

package com.example.demo.printer;

/**
 * Created by Admin on 2018/5/8.
 */
public interface Printer {
    void init();

    void print(String txt);
}

三、彩色打印機類

package com.example.demo.printer;

public class ColorPrinter implements Printer {
    @Override
    public void init() {
        System.out.println("啓動彩色打印機！");
    }

    @Override
    public void print(String txt) {
        System.out.println("打印彩色文字：".concat(txt));
    }
}

四、黑白打印機類

package com.example.demo.printer;

public class GrayPrinter implements Printer{

    @Override
    public void init() {
        System.out.println("啓動打印機");
    }

    @Override
    public void print(String txt) {
        System.out.println("打印黑白文字：".concat(txt));
    }
}

五、電腦類

package com.example.demo.printer;

/**
 * Created by Admin on 2018/5/8.
 */
public class Computer implements Computeable{

    Printer p;
    public Printer getP() {
        return p;
    }

    public void setP(Printer p) {
        this.p = p;
    }

    @Override
    public void inject(Printer p) {
        this.p = p;
    }
}

六、電腦實現的接口

package com.example.demo.printer;

public interface Computeable {
    void inject (Printer p);
}

七、測試類

package com.example.demo.printer;

public class TestComputer {
    public static void main(String[] args) {
        Printer p = (Printer) GetBeans.getBean("printer");
        Computer pcl = new Computer();
        pcl.inject(p);

        //實現不用new關鍵字建立打印機實例
        pcl.getP().print("打印測試頁...");
    }
}

八、配置文件

printer = com.example.demo.printer.ColorPrinter

九、效果：