JAVA 常用方法实例 继承

继承：是对于类的抽象
子类继承父类，就会拥有父类的方法和属性。
快捷键：Ctrl+H查看继承树

主程序App.java

public class App {
  public static void main(String[] args) {
    //1.实例化对象
    Student student = new Student();
    //2.传递参数
    student.test("魏君");
  }
}

父类Person.java

public class Person {
  protected String name = "june";
  public void print(){
    System.out.println("Person");
  }
}

子类Student.java

public class Student extends Person{
  private String name="weijun";
  public void test(String name){
    //3.调用参数
    System.out.println(name);
    //4.调用本类属性
    System.out.println(this.name);
    //5.调用父类属性
    System.out.println(super.name);
  }
}

执行结果

魏君
weijun
june

私有的方法和属性无法被继承

主程序App.java

public class App {
  public static void main(String[] args) {
    //1.实例化对象
    Student student = new Student();
    //2.传递的参数
    student.test();
  }
}

父类Person.java

public class Person {
  protected String name = "june";
  public void print(){
    System.out.println("Person");
  }
}

子类Student.java

public class Student extends Person{
  private String name="weijun";
  public void print(){
    System.out.println("Student");
  }
  public void test(){
    //3.调用类方法
    print();
    //4.调用本类方法
    this.print();
    //5.调用父类方法
    super.print();
  }
}

执行结果

Student
Student
Person