桥接模式

实验9：桥接模式

本次实验属于模仿型实验，通过本次实验学生将掌握以下内容：

1、理解桥接模式的动机，掌握该模式的结构；

2、能够利用桥接模式解决实际问题。

[实验任务]：两个维度的桥接模式
用桥接模式实现在路上开车这个问题，其中，车可以是car或bus，路可以是水泥路或沥青路。

类图

 源代码

/**
 * 抽象汽车类
 */
public abstract class Vehicle
{
    protected Road road;
 
    //为汽车设置行驶的马路
    public void setRoad(Road road)
    {
        this.road = road;
    }
 
    //抽象行驶方法
    public abstract void drive();
}
 
public class Bus extends Vehicle
{
    //bus的行驶方法
    @Override
    public void drive()
    {
        String carType = "bus";
        this.road.bedrive(carType);
    }
}
 
public class Car extends Vehicle
{
    //car的行驶方法
    @Override
    public void drive()
    {
        String carType = "car";
        this.road.bedrive(carType);
    }
}
 
public interface Road
{
    void bedrive(String carType);
}
 
public class ConcreteRoad implements Road
{
    //水泥路
    @Override
    public void bedrive(String carType)
    {
        System.out.println(carType+"在水泥路行驶");
    }
}
 
public class PitchRoad implements Road
{
    //沥青路
    @Override
    public void bedrive(String carType)
    {
        System.out.println(carType + "在沥青路行驶");
    }
}
 
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
 
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import java.io.File;
 
public class XMLUtil
{
    public static Object getBean(String args)
    {
        try
        {
            DocumentBuilderFactory dFactory = DocumentBuilderFactory.newInstance();
            DocumentBuilder builder = dFactory.newDocumentBuilder();
            Document doc;
            doc = builder.parse(new File("src/main/resources/config9.xml"));
            Node classNode = null;
            NodeList nl = doc.getElementsByTagName("className");
            if (args.equals("road"))
            {
                classNode = nl.item(0).getFirstChild();
            } else if (args.equals("vehicle"))
            {
                classNode = nl.item(1).getFirstChild();
            }
            String cName = classNode.getNodeValue();
            Class c = Class.forName(cName);
            Object obj = c.newInstance();
            return obj;
        }
        catch (Exception e)
        {
            e.printStackTrace();
            return null;
        }
    }
}
 
public class Client
{
    public static void main(String[] args)
    {
        //从xml配置文件动态获取汽车类型
        Vehicle vehicle = (Vehicle) XMLUtil.getBean("vehicle");
        //动态获取路的类型
        Road road = (Road) XMLUtil.getBean("road");
        //给汽车设置行驶的路
        vehicle.setRoad(road);
        //调用汽车的行驶方法
        vehicle.drive();
    }
}

config9.xml

<?xml version="1.0" encoding="UTF-8"?>
<config>
<className>Tutorial_9.ConcreteRoad</className>
<className>Tutorial_9.Bus</className>
</config>