设计模式之建造者模式

建造者模式在源码中常见的有：

手写一个建造者模式。以手机为例：

public class Phone {
    private String cpu;//cpu
    private String dianchi;//电池
    private String keyBoard;//按键
    private String screen;//屏幕

    public Phone(Builder builder){
        this.cpu = builder.cpu;
        this.dianchi = builder.dianchi;
        this.screen = builder.screen;
        this.keyBoard = builder.keyBoard;
    }

    public static class Builder{
        private String cpu;//cpu
        private String dianchi;//电池
        private String keyBoard;//按键
        private String screen;//屏幕

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

        public Builder setKeyBoard(String keyBoard) {
            this.keyBoard = keyBoard;
            return this;
        }
        public Builder setScreen(String screen){
            this.screen = screen;
            return this;
        }

        public Phone build(){
            return new Phone(this);
        }
    }
}