构造方法

格式：public 类名(){

     };

写了构造方法后，必须有一个空参数的构造方法

构造方法可以重载

package com.oracle.Demo05;

public class Employee {
     private String name;
     private int num;
     private double salary;
     public Employee(){ 
     }
     public Employee(String name){
         this.name = name;
     }
     public Employee(String name,int num,double salary){
         this(name);
         this.num = num;
         this.salary = salary;
     }
     public void show(){
         System.out.println("姓名:"+name+"\t工号:"+num+"\t工资:"+salary);
     }
}

构造方法在创建对象的时候使用1次，普通方法能多次调用