类和对象

定义一个类：

public class Student {
    String name;
    int age;
    public void student()
    {
        System.out.println("学习...");
    }
    public void eat(){
        System.out.println("吃饭...");
    }
}

定义一个测试类：

public class StudentTest {
    public static void main(String[] args) {
       Student stu1=new Student();
       stu1.name="张三";
       stu1.age=18;
        System.out.println(stu1.age);
        System.out.println(stu1.name);
       stu1.student();
       stu1.eat();
        System.out.println("-------------");
        Student stu2=new Student();
        stu2.name="李四";
        stu2.age=20;
        System.out.println(stu2.name);
        System.out.println(stu2.age);
        stu2.student();
        stu2.eat();
    }
}