java基础回顾

 

//通过super调用父类构造方法和隐藏方法

package mypack;

class Father {
	public Father() {
		// TODO Auto-generated constructor stub
		System.out.println("null father");
	}

	public Father(String name) {
		System.out.println("name = " + name);
	}

	public String toString() {
		// TODO Auto-generated method stub
		return "我是father";
	}
}

class Sun extends Father {
	int age = 20;

	public Sun() {
		// TODO Auto-generated constructor stub
		super("铁鹏");
	}

	public int getAge() {
		return age;
	}

	public void setAge(int age) {
		this.age = age;
	}

	public String toString() {
		// TODO Auto-generated method stub
		return super.toString();
	}
}

public class DemoFive {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Sun sun = new Sun();
		System.out.println(sun.toString());
		;
	}

}

　　

 枚举回顾

package reviewDemo;
//枚举

enum Color{
	Green,Blue,Yellow;
	
	@Override
	public String toString() {
		String ret = super.toString();
		switch (this) {
		case Green:
			ret = "绿色";
			break;
			
		case Blue:
			ret = "蓝色";
			break;
			
		case Yellow:
			ret = "黄色";
			break;

		default:
			break;
		}
		
		return ret;
	}
	
}

class Personp{
	Color c = Color.Blue;
	void show(){
		System.out.println(c);
	}
}

public class Demo18 {
	public static void main(String[] args) {
		Color []color = Color.values();
		for (Color c : color) {
			System.out.println(c);
		}
		new Personp().show();
	}
}
输出：
绿色
蓝色
黄色
蓝色

　　

枚举继承接口

interface I {
	void show();
}

enum Color implements I {
	RED() {
		public void show() {
		}
	},
	GREEN {
		public void show() {
		}
	},
	BLUE {
		public void show() {
		}
	};
}

enum Color0 implements I {
	RED(), GREEN, BLUE;
	public void show() {
	}
}

　　

this语句的用法

package pack;

//this语句用于构造函数之间相互调用,代表某个对象
//this只能放在构造函数的第一行

class Person{
	
	private String name;
	private int age;
	
	Person(){
		
	}
	
	Person(String name){
		this();
		this.name = name;
	}
	
	Person(String name,int age){
		this(name);	//this语句只用于调用其他构造方法,这个是调用Person(name),
//		Person(name);  //这条语句是非法的
		this.age = age;
	}
}


public class Demo{
	public static void main(String[] args) {
		StringBuffer sb = new StringBuffer();
		
	}
}