super关键字

使用super调用父类的构造方法
子类不继承父类的构造方法，因此，子类如果想使用父类的构造方法，必须在子类的构造方法中使用，必须使用关键字super来表示，而且super必须是子类构造方法中的头一条语句
Student5_6.java

public class Student5_6 {
	int number;
	String name;
	Student5_6(){
		
	}
	Student5_6(int number, String name){
		this.number= number;
		this.name= name;
	}
	public int getNumber(){
		return number;
	}
	public String getName() {
		return name;
	}
}

UniverStudent.java

public class UniverStudent extends Student5_6 {
	boolean isNarriage;//子类新增的结婚属性
	UniverStudent(int number, String name, boolean v){
		super(number, name);//调用父类的构造方法
	}
	public boolean getIsNarriage(){
		return isNarriage;
	}
}

Example5_6.java

public class Example5_6 {
	public static void main(String[] args) {
		UniverStudent zhangStudent= new UniverStudent(20111, "张三", false);
		int number= zhangStudent.getNumber();
		String name= zhangStudent.getName();
		boolean marriage= zhangStudent.getIsNarriage();
		System.out.println(name+ "的学号是: "+ number);
		if(marriage== true){
			System.out.println(name+ "已婚");
		}
		else {
			System.out.println(name+ "未婚");
		}
	}
}

使用super操作被隐藏的成员变量和方法
如果在子类中想使用被子类隐藏的成员变量或方法，可以使用关键字super，super.x、super.play()，就是访问和调用被子类隐藏的成员变量x和方法play()
Sum.java

public class Sum {
	int n;
	public double f(){
		double sum= 0;
		for(int i= 1; i<= n;i++){
			sum= sum+ i;
		}
		return sum;
	}
}

Average.java

public class Average extends Sum {
	double nm;
	public double fq(){
		double c;
		super.n= (int)nm;
		c= super.f();
		return c+ nm;
	}
	public double g(){
		double c;
		c= super.f();
		return c- nm;
	}
}

Example5_7.java

public class Example5_7 {
	public static void main(String[] args) {
		Average average= new Average();
		average.nm= 100.5678;
		double result1= average.fq();
		double result2= average.g();
		System.out.println("result1= "+ result1);
		System.out.println("result2= "+ result2);
	}
}