Question

JAVA编程问题 定义一个泛型类Point，它包含横坐标x和纵坐标y两个变量，类型均为T

该类具有两个参数的构造方法、x和y的设置器与访问器、输出方法。在main()函数中分别传入Double、Float、Integer类型数据加以验证。

Answer 1

public class Point<T> {
private T x;
private T y;

public Point(T x, T y) {
this.x = x;
this.y = y;
}

public T getX() {
return x;
}

public void setX(T x) {
this.x = x;
}

public T getY() {
return y;
}

public void setY(T y) {
this.y = y;
}

public void outPut(Point<T> p){
System.out.println("点的x坐标为:"+p.getX());
System.out.println("点的y坐标为:"+p.getY());
}

public static void main(String[] args) {
Point<Integer> p=new Point<Integer>(1,2);
p.outPut(p);

Point<Double> d=new Point<Double>(1.0,2.0);
d.outPut(d);

Point<Float> f=new Point<Float>(1.0f,2.0f);
f.outPut(f);

}

}

Answer 2

泛型，通俗点就是提前声明这个list中将来到底装什么东西
lines的泛型为list
list的泛型又是Point对象
通俗说法：lines中存放一堆list列表
而每个list中又存放一堆Point对象
跟多维数组很类似：
lines1
---list1
----Point1
----Point2
----Point3
----Point4
---list2
----Point5
----Point6
----Point7
----Point8
lines2
---list2
----Point1
----Point2
----Point3
----Point4
---list3
----Point5
----Point6
----Point7
----Point8