Java设计模式 - 生成器模式

以你之姓@ 2022-11-27 00:40 244阅读 0赞

**目录**

生成器模式（建造者模式）：

生成器优点：

生成器模式和抽象工厂模式区别：

生成器模式和策略模式区别：

生成器模式应用：

生成器实例：

类图：

示例：

代码：

上述代码 GitHub 地址：https://github.com/baicun/designPatterns

--------------------

# [生成器模式（][Link 1]建造者模式[）：][Link 1] #

封装一个复杂对象构建过程，并允许按步骤构造

# [生成器][Link 1][优点：][Link 2] #

将复杂对象的创建过程封装起来，只需要指定具体的生成器就能生成特定对象

# [生成器][Link 1][模式和抽象工厂模式区别：][Link 3] #

生成器在多步创建过程的最后一步返回产品，而抽象工厂则立即返回产品。

生成器关注的是分步创建复杂对象，很多时候同一类型的对象可以以不同的方式创建，而抽象工厂的重点在于创建简单或复杂的一整套组件。

# [生成器][Link 1][模式和策略模式区别：][Link 3] #

生成器模式是创建型的，也就是说用来创建对象的，而策略模式属于行为型模式，通过将行为封装成对象来降低类之间的耦合度

# [生成器][Link 1][模式应用：][Link 3] #

java.lang.StringBuilder\#append()，

java.lang.StringBuffer\#append()同样也是符合生成器模式，只不过方法加了synchronized，保证了线程安全。

# [生成器][Link 1][实例：][Link 4] #

## [类图：][Link 5] ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NzZG5fMDkxMQ_size_16_color_FFFFFF_t_70][]

## [示例：][Link 6] ##

生成旅游计划：旅游时，每天我们需要计划旅游景点、事项、时间、酒店，那一次假期可能是多个一天组成的，旅行社就会推出3天经典线路，4天经典线路...为了方便封装每天计划，我们用一个抽象类实现对应的功能，并具体拓展出不同天数的计划，最后由Director** **中进行选择。这个模式了一选择生成器模式。

## [代码：][Link 7] ##

每日计划实体：

public class VacationDay {
    	private Date mDate;
    	private String mHotels;
    	private ArrayList<String> mTickets = null;
    	private ArrayList<String> mEvents = null;
    
    	public VacationDay(Date date) {
    		mDate = date;
    		mTickets = new ArrayList<String>();
    		mEvents = new ArrayList<String>();
    	}
    
    	public void setDate(Date date) {
    		mDate = date;
    	}
    
    	public void setHotel(String mHotels) {
    		this.mHotels = mHotels;
    	}
    
    	public void addTicket(String ticket) {
    		mTickets.add(ticket);
    	}
    
    	public void addEvent(String event) {
    		mEvents.add(event);
    	}
    
    	public String showInfo() {
    		StringBuilder stb = new StringBuilder();
    		stb.append("Date:" + mDate.toString() + "\n");
    		stb.append("Hotel:" + mHotels + "\n");
    		stb.append("Tickets:" + mTickets.toString() + "\n");
    		stb.append("Events" + mEvents.toString() + "\n");
    
    		return stb.toString();
    	}
    }

假期实体：

public class Vacation {
    	private Date mStDate;
    	private int mDays = 0;
    	private VacationDay mVacationDay;
    	private ArrayList<VacationDay> mVacationDayLst;
    
    	public Vacation(String std) {
    		mVacationDayLst = new ArrayList<VacationDay>();
    		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
    		try {
    			mStDate = sdf.parse(std);
    			mVacationDay = new VacationDay(mStDate);
    			mVacationDayLst.add(mVacationDay);
    			mDays++;
    		} catch (ParseException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
    	}
    
    	public void setStDate(String std) {
    
    		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
    		try {
    			mStDate = sdf.parse(std);
    		} catch (ParseException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
    
    	}
    
    	public Date getStDate() {
    
    		return mStDate;
    	}
    
    	public void addDay() {
    
    		mVacationDay = new VacationDay(nextDate(mDays));
    		mVacationDayLst.add(mVacationDay);
    		mDays++;
    	}
    
    	public boolean setVacationDay(int i) {
    		if ((i > 0) && (i < mVacationDayLst.size())) {
    			mVacationDay = mVacationDayLst.get(i);
    			return true;
    		}
    		mVacationDay = null;
    		return false;
    	}
    
    	public void setHotel(String mHotels) {
    		mVacationDay.setHotel(mHotels);
    	}
    
    	public void addTicket(String ticket) {
    		mVacationDay.addTicket(ticket);
    	}
    
    	public void addEvent(String event) {
    		mVacationDay.addEvent(event);
    	}
    
    	public void showInfo() {
    		for (int i = 0, len = mVacationDayLst.size(); i < len; i++) {
    			System.out.println("** " + (i + 1) + " day**");
    			System.out.println(mVacationDayLst.get(i).showInfo());
    
    		}
    	}
    
    	private Date nextDate(int n) {
    		Calendar cal = Calendar.getInstance();
    		cal.setTime(mStDate);
    		cal.add(Calendar.DATE, n);
    		return cal.getTime();
    	}
    }

抽象生成器：

//抽象建造者
    public abstract class AbsBuilder {
    
    	public Vacation mVacation;
    
    	public AbsBuilder(String std) {
    		mVacation = new Vacation(std);
    	}
    
    	public abstract void buildvacation();
    
    	public abstract void buildDay(int i);
    
    	public abstract void addHotel(String hotel);
    
    	public abstract void addTicket(String ticket);
    
    	public abstract void addEvent(String tvent);
    
    	public Vacation getVacation() {
    
    		return mVacation;
    
    	}
    
    }

具体生成器：

public class Builder3d extends AbsBuilder {
    
        public Builder3d(String std) {
            super(std);
            // TODO Auto-generated constructor stub
    
        }
    
        @Override
        public void buildDay(int i) {
            // TODO Auto-generated method stub
    
            mVacation.setVacationDay(i);
    
        }
    
        @Override
        public void addHotel(String hotel) {
            // TODO Auto-generated method stub
            mVacation.setHotel(hotel);
        }
    
        @Override
        public void addTicket(String ticket) {
            // TODO Auto-generated method stub
            mVacation.addTicket(ticket);
        }
    
        @Override
        public void addEvent(String event) {
            // TODO Auto-generated method stub
            mVacation.addEvent(event);
        }
    
        @Override
        public void buildvacation() {
            // TODO Auto-generated method stub
            addTicket("Plane Ticket");
            addEvent("Fly to Destination");
            addEvent("Supper");
            addEvent("Dancing");
            addHotel("Four Seasons");
    
            mVacation.addDay();
            addTicket("Theme Park");
            addEvent("Bus to Park");
            addEvent("lunch");
            addHotel("Four Seasons");
    
            mVacation.addDay();
    
            addTicket("Plane Ticket");
            addEvent("City Tour");
            addEvent("Fly to Home");
    
        }
    
    }

Director包装类：

public class Director {
    	private AbsBuilder builder;
    	
    	public Director(AbsBuilder builder)
    	{
    		this.builder=builder;
    	}
    	public void setBuilder(AbsBuilder builder)
    	{
    		this.builder=builder;
    	}
    	public void construct()
    	{
    		builder.buildvacation();
    		builder.getVacation().showInfo();
    	}
    }

测试类：

public class MainTest {
    
    	public static void main(String[] args) {
    
    		Director mDirector = new Director(new Builder4d("2015-12-29"));
    
    		mDirector.construct();
    
    		mDirector.setBuilder(new Builder3d("2015-8-30"));
    		mDirector.construct();
    	}
    
    }

# [上述代码 GitHub 地址：https://github.com/baicun/designPatterns][GitHub _https_github.com_baicun_designPatterns] #

[Link 1]: https://blog.csdn.net/csdn_0911/article/details/107847456#%E4%BB%A3%E7%90%86%E6%A8%A1%E5%BC%8F%EF%BC%9A-toc-toc-toc-toc-toc-toc-toc-toc-toc-toc
[Link 2]: https://blog.csdn.net/csdn_0911/article/details/107847456#%E7%8A%B6%E6%80%81%E4%BC%98%E7%82%B9%EF%BC%9A
[Link 3]: https://blog.csdn.net/csdn_0911/article/details/107847456#%E7%8A%B6%E6%80%81%E6%A8%A1%E5%BC%8F%E5%BA%94%E7%94%A8%EF%BC%9A
[Link 4]: https://blog.csdn.net/csdn_0911/article/details/107847456#%E7%8A%B6%E6%80%81%E5%AE%9E%E4%BE%8B%EF%BC%9A
[Link 5]: https://blog.csdn.net/csdn_0911/article/details/107847456#%E7%B1%BB%E5%9B%BE%EF%BC%9A
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NzZG5fMDkxMQ_size_16_color_FFFFFF_t_70]: /images/20221124/d5cc3626e78742eab4316e0495bbc693.png
[Link 6]: https://blog.csdn.net/csdn_0911/article/details/107847456#%E7%A4%BA%E4%BE%8B%EF%BC%9A
[Link 7]: https://blog.csdn.net/csdn_0911/article/details/107847456#%E4%BB%A3%E7%A0%81%EF%BC%9A
[GitHub _https_github.com_baicun_designPatterns]: https://blog.csdn.net/csdn_0911/article/details/107847456#%E4%B8%8A%E8%BF%B0%E4%BB%A3%E7%A0%81%20GitHub%20%E5%9C%B0%E5%9D%80%EF%BC%9Ahttps%3A%2F%2Fgithub.com%2Fbaicun%2FdesignPatterns