System.out.printf；；String.format

class Apple{   public String name;   public String color;   public double weight;   public Apple()   {}   public Apple(String name,String color)   {     this.name=name;     this.color=color;   }    public  Apple(String name,String color,double weight)   {    //通过this调用另一个重载的构造器的初始化代码    this(name,color);    this.weight=weight;    }   public String toString(){//System.out.printf("name:%s,color:%s,weight:%lf\n",name,color,weight);System.out.printf("name:%s,color:%s,weight:%f\n",name,color,weight);return String.format("name:%s,color:%s,weight:%f\n",name,color,weight);}}public class TestApple{public static void main(String[] args) {String name="apple";String color="red";double weight=1.5;Apple obj=new Apple(name,color,weight);System.out.println(obj);}}/*name:apple,color:red,weight:1.500000name:apple,color:red,weight:1.500000请按任意键继续. . .*/