接口定义类

IinkBox.java

package printerDemo.iface;

public interface IInkBox {
    public String getColor();
}

IPaper.java

package printerDemo.iface;

public interface IPaper {
    String getSize();
}

接口实现类

A4PaperImpl.java

package printerDemo.impl;

import printerDemo.iface.IPaper;

public class A4PaperImpl implements IPaper{

    @Override
    public String getSize() {
        return "A4";
    }

}

B5PaperImpl.java

package printerDemo.impl;

import printerDemo.iface.IPaper;

public class B5PaperImpl implements IPaper{

    @Override
    public String getSize() {
        return "B5";
    }

}

ColorInkBoxImpl.java

package printerDemo.impl;

import printerDemo.iface.IInkBox;

public class ColorInkBoxImpl implements IInkBox{

    @Override
    public String getColor() {
        return "红色";
    }

}

核心“业务”类

Printer.java
核心“业务”类

package printerDemo;

import printerDemo.iface.IInkBox;
import printerDemo.iface.IPaper;

public class Printer {
    private IInkBox inkBox = null;
    private IPaper paper = null;
    
    public void print(String content) {
        if(null == inkBox || null == paper) {
            System.out.println("墨盒和纸张出现错误");
            return;
        }
        String color = inkBox.getColor();
        String type = paper.getSize();
        System.out.println("以下文字是" + color + "色的");
        System.out.println("使用纸张：" + type);
        System.out.println("打印内容：" + content);
    }

    public IInkBox getInkBox() {
        return inkBox;
    }

    public void setInkBox(IInkBox inkBox) {
        this.inkBox = inkBox;
    }

    public IPaper getPaper() {
        return paper;
    }

    public void setPaper(IPaper paper) {
        this.paper = paper;
    }

}

PrinterTest.java
主函数

package printerDemo;

import printerDemo.impl.A4PaperImpl;
import printerDemo.impl.B5PaperImpl;
import printerDemo.impl.ColorInkBoxImpl;

public class PrinterTest {
    public static void main(String[] args) {
        Printer printer = new Printer();
        
        printer.setInkBox(new ColorInkBoxImpl());
        printer.setPaper(new A4PaperImpl());
        printer.print("测试内容");
        printer.setPaper(new B5PaperImpl());
        printer.print("测试内容");
    }
}