构造方法的重载

 

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package com.liaojianya.chapter1; /**  * This program demonstrates the correct use of construct overload.  * @author LIAO JIANYA  * 2016年7月21日  */ public class ConstructOverload {     public static void main(String[] args)     {         Person2 p = new Person2();         Person2 p1 = new Person2(33);         Person2 p2 = new Person2("wangxiaoyuan", 23);         p.talk();         p1.talk();         p2.talk();     }   } class Person2 {     private String name;     private int age;           public Person2()     {         name = "zhangsan";         age = 22;     }           public Person2(int age)     {         name = "wangyuan";         this.age = age;     }           public Person2(String name, int age)     {         this.name = name;         this.age = age;     }           public void talk()     {         System.out.println("My name is " + name + ", I am " + age + " years old.");               }       }

　　运行结果：

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My name is zhangsan, I am 22 years old. My name is wangyuan, I am 33 years old. My name is wangxiaoyuan, I am 23 years old.

　　分析：1、第一个构造方法是无参构造，第二个，第三个是有参构造，当对象实例化时，根据new出来对象中是否无参还是有参以及参数个数来调用对应的构造方法。

　　　　　2、三个构造方法形成了构造方法的重载。