到底什么是多态?? public void setValue(String value){}public void setValue(float value){}public void setValue(int value){}方法名相同,参数不同。 解决方案 » 免费领取超大流量手机卡,每月29元包185G流量+100分钟通话, 中国电信官方发货 楼上错了,你说的是方法重载。多态就是多种形态,利于类型匹配,因为Java是强类型语言,而有些时候类型不一定能够完全匹配,所以就产生了多态。 //: c12:Shapes.java// From 'Thinking in Java, 2nd ed.' by Bruce Eckel// www.BruceEckel.com. See copyright notice in CopyRight.txt.import java.util.*;class Shape { void draw() { System.out.println(this + ".draw()"); }}class Circle extends Shape { public String toString() { return "Circle"; }}class Square extends Shape { public String toString() { return "Square"; }}class Triangle extends Shape { public String toString() { return "Triangle"; }}public class Shapes { public static void main(String[] args) { ArrayList s = new ArrayList(); s.add(new Circle()); s.add(new Square()); s.add(new Triangle()); Iterator e = s.iterator(); while(e.hasNext()) ((Shape)e.next()).draw(); }} ///:~这是《Thinking in Java》里的一个例程,通常多态总是跟继承、向上转型、动态绑定等分不开,弄清楚这些概念后就很容易理解。祝你成功! public class MultiConstructor{ //成员变量 int variable1; int variable2; int variable3; //构造方法1 private MultiConstructor() { } //构造方法2 private MultiConstructor(int variable1) { this.variable1 = variable1; } //构造方法3 private MultiConstructor(int variable1,int variable2) { this.variable1 = variable1; this.variable2 = variable2; } //构造方法4 private MultiConstructor(int variable1,int variable2,int variable3) { this.variable1 = variable1; this.variable2 = variable2; this.variable3 = variable3; }} 数组中去出所有0, 在看一个开源ESB项目MULE的源代码的时候遇到一个问题,请大家帮忙 内存 如何把一个日期类型的2008-7-16 16:07:43秒 JAVA中文编码问题 这段代码的同步总是无法实现,求帮助 <html:errors/> 如何换行 Tree中删除叶子的问题 有关窗体的问题 方法的调用? 关于J2SE连接MySQL 这个程序会不会死锁
// From 'Thinking in Java, 2nd ed.' by Bruce Eckel
// www.BruceEckel.com. See copyright notice in CopyRight.txt.
import java.util.*;class Shape {
void draw() {
System.out.println(this + ".draw()");
}
}class Circle extends Shape {
public String toString() { return "Circle"; }
}class Square extends Shape {
public String toString() { return "Square"; }
}class Triangle extends Shape {
public String toString() { return "Triangle"; }
}public class Shapes {
public static void main(String[] args) {
ArrayList s = new ArrayList();
s.add(new Circle());
s.add(new Square());
s.add(new Triangle());
Iterator e = s.iterator();
while(e.hasNext())
((Shape)e.next()).draw();
}
} ///:~
这是《Thinking in Java》里的一个例程,通常多态总是跟继承、向上转型、动态绑定等分不开,弄清楚这些概念后就很容易理解。祝你成功!
{
//成员变量
int variable1;
int variable2;
int variable3;
//构造方法1
private MultiConstructor()
{
}
//构造方法2
private MultiConstructor(int variable1)
{
this.variable1 = variable1;
}
//构造方法3
private MultiConstructor(int variable1,int variable2)
{
this.variable1 = variable1;
this.variable2 = variable2;
}
//构造方法4
private MultiConstructor(int variable1,int variable2,int variable3)
{
this.variable1 = variable1;
this.variable2 = variable2;
this.variable3 = variable3;
}}