20.Java基础_对象的构造函数

 1 package pack1;
 2 public class Student {
 3     private String name;
 4     private int age;
 5 
 6     //构造方法
 7     //如果没有任何构造函数,系统会自动给一个无参构造函数
 8     public Student(){
 9         this.name="";
10         this.age=0;
11     }
12     public Student(String name,int age){
13         this.name=name;
14         this.age=age;
15     }
16 
17     public void show(){
18         System.out.println(name+","+age);
19     }
20 }

package pack1;
//测试学生类

public class StudentDemo {
    public static void main(String[] args) {
        // 创建对象
        Student s1=new Student();
        Student s2=new Student("njt",22);
        s1.show(); //  ,0
        s2.show(); // njt,22
    }
}