工厂模式

一般涉及到new 操作符 创建对象需要大量重复的代码 客户端不依赖产品类实例如何被创建、实现等细节

1.js实现方法

UML类图

实现代码

class Prodect{
    constructor(name){
        this.name = name
    }

    init(){
        console.log('init')
    }

    fn(){
        console.log('fn')
    }
}

class Create{
    create(name){
        return new Prodect(name)
    }
}

//test
let factory = new Create();
let p = factory.create('a')
console.log(p.name)
p.init()
p.fn()

场景实现

1. jQuery $("div")

class jQuery{
    constructor(selector){
        let slice = Array.prototype.slice
        let dom = slice.call(document.querySelectorAll(selector)) //将多个dom节点转化为数组
        let len = dom ?dom.length :0
        for(let i =0;i<len;i++){
            this[i] = dom[i]
        }
        this.length = len
        this.selector = selector || ''

    }

    append(node){

    }

    addClass(name){

    }

    html(data){

    }

    //此处省略n个api
}

window.$ = function(selector){
    return new jQuery(selector)
}

2.React.createElement

class Vnode(tag,attrs,children{

}

React.createElement = function(tag,attrs,children){
    return new Vnode(tag,attrs,children)
}

//使用

React.createElement('div','data',null)

2.java实现方法

代码

//Video.class
public abstract class Video {
    public abstract void produce();
}

//JavaVideo
public class JavaVideo extends Video{

    @Override
    public void produce() {
        System.out.print("JavaVideo");

    }

}

// VideoFactory
public abstract class VideoFactory {
    public abstract Video getVideo();
}

// JavaVideoFactory
public class JavaVideoFactory extends VideoFactory{

    @Override
    public Video getVideo() {
        return new JavaVideo();
    }

}

//  Test
public class Test {

    public static void main(String[] args) {

        VideoFactory videoFactory = new JavaVideoFactory();
        Video video = videoFactory.getVideo();
        video.produce();

    }

}