设计模式--建造者模式、单例模式、适配器模式

建造者模式

类图

 

 

源码

package com.bulid;

public class Computer {

    private String cpu;//必须
    private String ram;//必须
    private int usbCount;//可选
    private String keyboard;//可选
    private String display;//可选

    private Computer(Builder builder) {
        this.cpu = builder.cpu;
        this.ram = builder.ram;
        this.usbCount = builder.usbCount;
        this.keyboard = builder.keyboard;
        this.display = builder.display;
    }

    public static class Builder {
        private String cpu;//必须
        private String ram;//必须
        private int usbCount;//可选
        private String keyboard;//可选
        private String display;//可选

        public Builder(String cpu, String ram) {
            this.cpu = cpu;
            this.ram = ram;
        }

        public Builder setUsbCount(int usbCount) {
            this.usbCount = usbCount;
            return this;
        }

        public Builder setKeyboard(String keyboard) {
            this.keyboard = keyboard;
            return this;
        }

        public Builder setDisplay(String display) {
            this.display = display;
            return this;
        }

        public Computer builder() {

            return new Computer(this);
        }

    }

    @Override
    public String toString() {
        final StringBuilder sb = new StringBuilder("Computer{");
        sb.append("cpu='").append(cpu).append('\'');
        sb.append(", ram='").append(ram).append('\'');
        sb.append(", usbCount=").append(usbCount);
        sb.append(", keyboard='").append(keyboard).append('\'');
        sb.append(", display='").append(display).append('\'');
        sb.append('}');
        return sb.toString();
    }
public static void main(String[] args) {
    // 建造正模式
    Computer computer = new Computer.Builder("因特尔", "三星")
            .setDisplay("三星24寸")
            .setKeyboard("罗技")
            .setUsbCount(2)
            .builder();
    System.out.println(computer);
}
}

 

 

测试截图

 

 

单例模式

类图

 

源码

package com.test;

public class StuNo {
    private static StuNo instance=null;
    private String no;
    
    private StuNo()
    {    
    }
    
    public static StuNo getInstance()
    {
        if(instance==null)
        {
            System.out.println("入学，分配学号！");
            instance=new StuNo();
            instance.setStuNo("20193922");        
        }
        else
        {
            System.out.println("返校，获取旧号码！");  
        }
        return instance;
    }
    
    private void setStuNo(String no)
    {
        this.no=no;
    }
    
    public String getStuNo()
    {
        return this.no;
    }
}


Client.java
package com.test;

public class Client {
    public static void main(String a[])
    {
        StuNo no1,no2;
       no1=StuNo.getInstance();
       no2=StuNo.getInstance();
       System.out.println("学号是否一致：" + (no1==no2));
       
       String str1,str2;
       str1=no1.getStuNo();
       str2=no1.getStuNo();
       System.out.println("第一次学号：" + str1);
       System.out.println("第二次学号：" + str2);
       System.out.println("内容是否相等：" + str1.equalsIgnoreCase(str2));
       System.out.println("是否是相同对象：" + (str1==str2));
    }
}

 

测试截图

 

 

 

 适配器模式

类图

 

源码

package adapter;

public interface Cat {
    public void requestCat();
    public void miao();
}

Dog.java
package adapter;

public interface Dog {
    public void requestDog();
    public void wang();
}

ClassAdapterDog.java
package adapter;

public class ClassAdapterDog extends Adaptee implements Dog{
    public void requestDog()    
    {        
        specificCat();    
    }

    @Override
    public void wang() {
        // TODO 自动生成的方法存根
        System.out.println("狗汪汪叫！");
    }
}
ClassAdapterCat.java
package adapter;

public class ClassAdapterCat extends Adaptee implements Cat{
    public void requestCat()    
    {        
        specificDog();    
    }

    @Override
    public void miao() {
        // TODO 自动生成的方法存根
        System.out.println("猫抓老鼠！");
    }
}

Adaptee.java
package adapter;

public class Adaptee {
    public void specificCat()    
    {               
        System.out.println("猫学：");
    }
    public void specificDog()    
    {               
        System.out.println("狗学：");
    }  
}

ClassAdapterTest.java
package adapter;

public class ClassAdapterTest {
    public static void main(String[] args)    
    {        
        System.out.println("测试：");        
        Dog target = new ClassAdapterDog();        
        target.requestDog();
        target.wang();
        Cat target1 = new ClassAdapterCat();
        target1.requestCat();
        target1.miao();
    }
}

 

 

测试截图