[关闭]
@Sarah 2015-11-05T17:47:48.000000Z 字数 5892 阅读 929

JAVA 生日 色彩 多态 接口

java笔记
上堂课的例子更新正确版本

1时间/生日

  1. public class Time {
  2.     int hour, minute, second;
  4.     Time(int hour, int minute, int second) {
  5.         this.hour = hour;
  6.         this.minute = minute;
  7.         this.second = second;
  8.     }
  10.     Time(int hour, int minute) {
  11.         this.hour = hour;
  12.         this.minute = minute;
  13.         second = 0;
  14.     }
  16.     Time(int hour) {
  17.         this.hour = hour;
  18.         minute = 0;
  19.         second = 0;
  20.     }
  21.     public void nextSecond(){
  22.         second++;
  23.         if(second==60){
  24.             second=0;
  25.             minute++;
  26.             if(minute==60){
  27.                 minute=0;
  28.                 hour++;
  29.                 if(hour==24)
  30.                     hour=0;             
  31.             }
  32.         }
  33.     }
  34.     public void nextSecond(long s){
  35.         for(int i=0;i<s;i++) nextSecond();
  36.     }
  38.     @Override//覆盖
  40.     public String toString() {
  41.         return super.toString()+"[hour=" + hour + ", minute=" + minute + ", second="
  42.                 + second + "]";
  43.     }
  45. }
  1. import java.awt.KeyboardFocusManager;
  3. public class Date {
  5.     int year, month, day;
  7.     Date(int year, int month, int day) {
  8.         this.year = year;
  9.         this.month = month;
  10.         this.day = day;
  11.     }
  13.     Date(int year, int month) {
  14.         this.year = year;
  15.         this.month =month;
  16.         day = 1;
  17.     }
  19.     Date(int year) {
  20.         this.year = year;
  21.         day = 1;
  22.         month = 1;
  23.     }
  27.     public void nextDay() { // a过了1天以后是什么日期
  28.         if(month==2 && day==28){
  29.             if (year % 4 == 0 && year % 100 != 0 || year % 400==0){
  30.                 day++;
  31.             }
  32.             else{
  33.                 month=3;
  34.                 day=1;
  35.             }
  36.         }
  37.         else if(day==29 &&month==2){
  38.             month=3;
  39.             day=1;
  40.         }
  41.         else    if(day==30){
  42.             if(month==4 || month==6 || month==9 || month==11){
  43.                 month++;
  44.                 day=1;
  45.             }
  46.             else {
  47.                 day++;
  48.             }
  49.         }else if(day==31){
  50.             month++;
  51.             if(month==13){
  52.                 month=1;
  53.                 year++;
  54.             }
  55.             day=1;
  56.         }
  57.         else {
  58.             day++;
  59.         }
  60. //      return new Date(year,month,day);
  61.     }
  63.     @Override
  64.     public boolean equals(Object obj) {
  66.         if (this == obj)
  67.             return true;
  68.         if (obj == null)
  69.             return false;
  70.         if (getClass() != obj.getClass())
  71.             return false;
  72.         Date other = (Date) obj;
  73.         if (day != other.day||month != other.month||year != other.year)
  74.             return false;
  75.         return true;
  76.     }
  78.     @Override
  79.     public String toString() {
  80.         return "Date [year=" + year + ", month=" + month + ", day=" + day + "]";
  81.     }
  83. }
  1. public class Birthday {
  2.     Date x;
  3.     Time y;
  5.     Birthday(Date a, Time b) {
  6.         x = a;
  7.         y = b;
  8.     }
  10.     Birthday(Date a) {
  11.         x = a;
  12.         y = new Time(0, 0, 0);
  13.     }
  15.     Birthday(int year, int month, int day, int hour, int minute, int second) {
  16.         x = new Date(year, month, day);
  17.         y = new Time(hour, minute, second);
  18.     }
  20.     public long birthdayTo(Date x) {// 计算过了多少天
  21.         long k = 1;
  22.         Date temp=new Date(this.x.year,this.x.month,this.x.day);
  23.         while (true) {
  24.             temp.nextDay();
  25.             //System.out.println(temp);
  26.             if (temp.equals(x))
  27.                 return k;
  28.             else 
  29.                 k++;
  30.         }
  31.         //return 0;
  32.     }
  34.     @Override
  35.     public String toString() {
  36.         return "Birthday [x=" + x + ", y=" + y + "]";
  37.     }
  39. }
  1. public class Test {
  3.     public static void main(String[] args) {
  4.         // TODO Auto-generated method stub
  5.         Date i=new Date(1992, 11, 23);
  6.         Date ii=i;
  7.         Time m=new Time(20, 45, 22);
  8.         System.out.println(i.hashCode());
  9.         System.out.println(ii.hashCode());
  10. //System.out.println(m);
  11. //m.nextSecond(60);
  12. //System.out.println(m);
  13.         Birthday c=new Birthday(i, m);
  15.         Date j=new Date(1993, 11, 23);
  16.         Birthday d=new Birthday(j);
  19.         System.out.println(c.birthdayTo(j));
  20.         System.out.println(c.toString());
  21.     }
  24.     }

2色彩点案例

坐标上一点，既有坐标，也有颜色

  1. package color;
  3. public class Point {
  4.     int x,y;
  5.     public Point(){
  6.         this(0,0);
  7.     }
  8.     public Point(int bb){
  10.     }
  11.     public Point(int x,int y){ 
  12.         this.x=x;
  13.         this.y=y;
  14.     }
  15.     Point getPoint(){
  16.         Point p=new  Point();
  17.         p.setX(-x);
  18.         p.setY(-y);
  19.         return p;
  21.     }
  22.     public void setX(long xx){
  23.         x=(int)xx;
  24.     }
  26.     void setX(int xx){
  27.         x=xx;
  28.     }
  29.     void setY(int yy){
  30.         y=yy;
  31.     }
  32.     Point getApoint(){   //新函数 返回值是point
  33.         Point q=new Point(-x,-y);
  35.         return q;
  36.     }
  37.     public double distance(Point p2){ //point是原来的点坐标，p2是另一点的坐标
  38.         double d=0;
  39.         d=Math.sqrt((x-p2.x)*(x-p2.x)+(y-p2.y)*(y-p2.y));
  40.         return d;
  41.     }
  42.     public boolean equals(Point p3){
  43.         if (p3.x==x && p3.y==y) {
  44.             return true;
  46.         }
  47.         else {
  48.             return false;
  49.         }
  50.     }
  52.     public String toString(){
  53.         return  "["+x+","+y+"]";
  54.     }
  55.     public int getX(){
  56.         return x;
  58.     }
  59.     public int getY() {
  60.         return y;
  61.     }
  63. }
  1. package color;
  3. public class Test {
  5.     public static void main(String[] args) {
  6.          Point p3=new Point();
  7.          Point p2=new Point(0,0);
  8.         Color c=new Color(255,0,0);
  9.         ColoredPoint p1=new ColoredPoint(255, 255)  ;
  10.         Color c1=new Color(p1,255);
  12.         int k=c.TestColor(c);
  13. //      int k=c1.TestColor(c1);
  14.         System.out.println("p1"+p1);
  15.         switch(k){
  16.         case 1:
  17.         System.out.print("white");
  18.         break;
  19.         case 2:
  20.         System.out.print("black");
  21.         break;
  22.         case 3:
  23.         System.out.print("red");
  24.         break;
  25.         case 4:
  26.         System.out.print("green");
  27.         break;
  28.         case 5:
  29.         System.out.print("blue");
  30.         break;
  31.         case 6:
  32.         System.out.print("other color");
  33.         break;
  34.         }
  35.     }
  36. }
  1. package color;
  3. public class Color {
  4.     int r, g, b;
  6.     public Color() {
  8.     }
  10.     public Color(int x, int y, int z) {
  11.         r =x;
  12.         g = y;
  13.         b =z;
  14.     }
  16.     public Color(Point a,int b){
  17.          a=new Point(0,0);
  18.          b=this.b;
  19.     }
  22.     int TestColor(Color a) {
  23.         if (r == 255 && g == 255 && b == 255)
  24.             return 1;// white
  25.         else if (r == 0 && g == 0 && b == 0)
  26.             return 2;// black
  27.         else if (r == 255 && g == 0 && b == 0)
  28.             return 3;// red
  29.         else if (r == 0 && g == 255 && b == 0)
  30.             return 4;// green
  31.         else if (r == 0 && g == 0 && b == 255)
  32.             return 5;// blue
  33.         else
  34.             return 6;
  36.     }
  38.     @Override
  39.     public String toString() {
  40.         return "[r=" + r + ", g=" + g + ", b=" + b + "]";
  41.     }
  43. }
  1. package color;
  3. public class ColoredPoint extends Point {
  4.     Color color;
  6.     ColoredPoint(int x, int y) {
  7.         this(x,y,0,0,0);
  8.     }
  10.     ColoredPoint(int x, int y, int r,int g,int b) {
  11.         color = new Color(r,g,b);
  12.         this.x = x;
  13.         this.y=y;
  14.     }
  15.     ColoredPoint(int r,int g,int b) {
  16.         this(0,0,r,g,b);
  17.     }
  19.     @Override
  20.     public String toString() {
  21.         return "[color=" + color + ", x=" + x + ", y=" + y + "]";
  22.     }
  24. }

3interface案例

  2. public class A {
  4. }
  1. public interface B {
  2.     int f();
  3.     void g();
  4.     int i=10;
  5. }
  1. public abstract class C implements B{
  2.     void t(){
  3.         System.out.println("-----");
  4.     }
  5. }
  1. public class D extends C{
  3.     @Override
  4.     public int f() {
  5.         // TODO Auto-generated method stub
  7.         return 0;
  8.     }
  10.     @Override
  11.     public void g() {
  12.         // TODO Auto-generated method stub
  14.     }
  16. }

5不知道什么例子。。。

  1. public class Person {
  2.     int age;
  3.     static int count=0;
  4.     Person(int age){
  5.         this.age=age;
  6.         count++;
  7.     }
  8.     public static void main(String[] args) {
  9.         Person p1=new Person(10);
  10.         System.out.println(p1.count);
  11.         Person p2=new Person(20);
  12.         System.out.println(p2.count);
  13.     }
  14. }

判断两个点是否相等，可以用

  1. p1.equals(p2)

而不是复杂的

  1. if(p.x==x&&p.y==y)

object:
是所有包的父类
定义了所有类应该具有的函数
如 equals()
toString()
(自带的toString()打印的是16进位的哈希码@)

数据结构：

树
线性表：数组-链表-哈希表
图：

  1. class Node{
  2. int i;
  3. Node next;
  4. }
  6. Node a=new Node();
  7. a.i=10;
  8. Node b=new Node();
  9. b.i=11
  10. a.next=b;

static

static方法：静态
static变量；静态

static方法：

形式 类名.方法名（）
不能访问非static变量、方法

一般的方法：

对象.方法（）

static变量：

类变量，所有类的对象共用

final

final类：不能继承
final方法：不能覆盖
final变量：常量

  1. class A{
  2.     final f(){}
  3.     g(){}
  4.     }
  5. ///    
  7. class{
  8.     f(){}
  9. }
  11. ///
  12. class A{
  13.     static fanel int i= 10;
  14.     }
  15. ///
  16. ///无statac 
  17. a=new.A();
  18. a.i

多态

1方法重载引起
2方法覆盖

  1. ///方法覆盖案例
  2. A{
  3.     f(){--}
  4. }
  6. B extends A{
  7.     f(){1}
  8. }
  10. C extends A{
  11.     f(){2}
  12. }
  15. A a=new B();
  16. a.f(); //调用B类1
  17. a= new c();
  18. a.f();//调用C类2

抽象类

不能直接实例化成对象

A:
g() {}
abstract f();

B:
g(){}
f(){}

C:
(){}
f(){}

abstract class A{ }
abstract void f();//继承
void g(){}
A a=new A();
a.g();
a.f()?

abstract class Shape{
public double area();
三角a()
圆b()
矩形c()

接口

interface
纯抽象类，即没有任何具体方法

类f() {}
抽象类1 抽象类2

..............A.............

A a=new A();
a.f();

A不知道调用1 还是2，JAVA不允许

接口f();

子接口f(1) 子接口f(2)

B f()
A af()

class A{}
interface B{}
int f();------------public int f（）；
void g();---------public void g();
int i=10;--------- public static final int i=10;

absteact
class C implements B{
i=10;
abstract
}
↑
C
↑
D

接口的作用

1多重继承

此处输入图片的描述

2不同的时期代码的公共接口

此处输入图片的描述

添加新批注
在作者公开此批注前，只有你和作者可见。
回复批注