Javakeyword之this

public class ThisDemo {

    public ThisDemo()
    {
        this.number=20;
    }
    public ThisDemo(int number,int number2)
    {
        this();//调用无參数的构造函数
        this.number2=number2;
    }
    ThisDemo increment(){
        number++;
        number2++;
        return this;
    }
    private void print(){
        System.out.println("number="+number+";number="+number2);
    }
    public static void main(String[] args) {
        ThisDemo tt=new ThisDemo();
        tt.increment().increment().increment().print();
    }
}