day05大数据学习

一、方法

基本数据类型

//形参：用于接收实际参数的变量

//实参：实际参与运算的变量

import java.util.Arrays;

public class Test {

public static void main(String[] args) { int x = 10; int y = 5; System.out.println("x:" + x +",y:" + y);//10，5 changeNumber(x,y);//调用方法，运行changeNumber,调用完释放 System.out.println("x:" + x +",y:" + y);//x:10,y:5； } //形参的改变不会引起实参的改变，基本数据类型 public static void changeNumber(int x,int y){ y = x; y = x + y; System.out.println("x:" + x +",y:" + y);//x:10;y:20第二个 }

}

引用数据类型

import java.util.Arrays;

/**

引用数据类型：数组，放在堆中方法参数：引用数据类型，形参改变会引起实参改变@author Administrator * */

public class MethodTest {

public static void main(String[] args) { //定义数组 int[] arr = {1,2,5}; //遍历元素 for(int i = 0; i < arr.length; i++){ System.out.println(arr[i]); } //调用方法 changeNumber(arr); for(int i = 0; i < arr.length; i++){ System.out.println(arr[i]); } System.out.println(Arrays.toString(arr)); } public static void changeNumber(int[] arr){ for(int i = 0; i < arr.length; i++){ if(arr[i]%2 == 0){ arr[i] *= 3;//取到偶数*3 } } } }

面向对象

1、面向对象思想

A、面向过程

强调的是过程，所有事情都需要自己完成

B、面向对象 根据客户需求， 高内聚，低耦合

是一种更符合我们思想习惯的思想（懒人思想）可以将复杂的问题简单化（对使用者说简单了，对象里面还是复杂的）将我们从执行者变成了指挥者

定义类的成员变量

类的定义包括“成员变量‘的定义和”方法“的定义，用于描述对象的行为，封装对象的功能。

成员变量在哪定义，作用域

求和的重载就近原则：char类型转化为int类型Java中方法的调用参考两点：1）方法签名2）就近原则System.out.println()也是一个重载@author Administrator class Adds{ public int add;

public class AddDemo {

public void main(String[] args) { Adds ad = new Adds(); System.out.println(ad.add +('0',5)); }

}

//void无返回值；int有返回值 public int add(int x ,int y){ System.out.println("1-"); return x + y; } public int add(int x){ System.out.println("2-"); return x + x; } public double add(double x, double y){ System.out.println("3-"); return x + y; } //add(int y, int x)跟上边一样，方法重复

// public int add(int y,int x){

// return x + y;

// }

//}

练习

/**

手机类：型号：String颜色：String给name打电话，发name发短信，@author Administrator *构造方法：(构造器) *1、构造方法声明在类内部 *2、方法名与类名相同 *3、不能声明返回值类型 *4、构造方法可以包含参数，参数一般是创建对象实例所依赖的条件 *如果不写构造方法：系统会默认提供一个无参构造 */

public class Phone {

//成员变量 String name; String color; //构造方法 //无参构造 public Phone(){ } //有参构造 public Phone(String name, String color){ this.name = name; this.color = color; } //方法 public void call(String name){ System.out.println("给" + name + "打电话"); } public void faDuanXin(String name){ System.out.println("给" + name + "发短信"); } public void printPhoneInfo(){ System.out.println("手机：" + name + "颜色：" + color); } }

测试类

public class Cha {

public static void main(String[] args) { Phone stu = new Phone(); stu.name = "pipi"; stu.color = "blue"; stu.call("acc"); stu.faDuanXin("pdd"); stu.printPhoneInfo(); Phone p = new Phone("iphone Sx max","红色"); p.printPhoneInfo(); }

}

继承

public class ExtendsDemo {

public static void main(String[] args) { LOL l = new LOL("tencent", 111, "pdd"); l.printInfo(); l.name ="ad"; l.version =1; l.agent= "tencent"; l.player="pdd"; l.start(); l.stop(); }

}

class Game{

String name; int version; String agent; boolean isPc; public Game(String name, int version,String agent){ this.name = name; this.version = version; this.agent = agent; this.isPc = true; } public void start(){ System.out.println("游戏启动"); } public void stop(){ System.out.println("游戏结束"); } public void printInfo(){ System.out.println(name +","+version + agent); }

}

class LOL extends Game{

String player; public LOL (String name,int version,String agent){ super(name,version,agent); this.player = player; } public void start(){ System.out.println("游戏启动后先进行更新……"); System.out.println("游戏玩家" + player ); }

}

class Honor extends Game{

public Honor(String name,int version,String agent,boolean isPc){ super(name,version,agent); }

}

方法的签名：方法名称+参数列表@author Administrator

public class OverLoadDemmo {

//现金方式 public void payByCash(double money){ System.out.println("使用现金支付"); } //银行卡 public void payByCard(String username,String password,double money){ System.out.println("使用银行卡支付"); } //支票 public void payByCheck(double money){ System.out.println("使用支票支付"); } public void pay(String username, String password){ System.out.println("使用信用卡支付"); } //方法的重载，方法名称相同，参数列表不同 public void pay(double money,String name){ System.out.println("使用现金支付"); } }

练习

学生类：姓名，性别，年龄，成绩女的，190，打游戏，做饭 苍老师@author Administrator *添加构造方法，并进行测试 */

public class Student {

//成员变量--特征，属性 String name; int age; double score; //方法行为 public void play() { System.out.println("打游戏"); } public void study(){ System.out.println("学习"); } public void printStudentInfo(){ System.out.println("姓名：" + name + "年龄" + age +"成绩" + score); } //构造方法 public Student(String name, int age, double score){ this.name = name; this.age = age; this.score = score; } }

package cn.tedu.day05;

public class Test01 {

public static void main(String[] args) { //构造方法输出 Student stu = new Student("qq", 110, 50); stu.printStudentInfo(); //方法 stu.name = "pipi"; stu.age = 18; stu.score = 88; stu.printStudentInfo(); stu.study(); stu.play(); Student stu1 = new Student(null, 0, 0); stu1.name = "baby"; stu1.age = 18; stu1.score = 88; stu1.printStudentInfo(); stu1.study(); stu1.play(); Student stu2 = new Student(null, 0, 0); stu2.name = "aa"; stu2.age = 18; stu2.score = 88; stu2.printStudentInfo(); stu2.study(); stu2.play(); } public static void printlnstudentInfo(Student stu){ System.out.println("姓名：" + stu.name + "年龄" + stu.age +"成绩" + stu.score); } } /*String name = "pipi"; int age = 18; int score = 76; printStudentInfo(name, age, score); String name1 = "oioi"; int age1 = 18; int score1 = 76; printStudentInfo(name1, age1, score1); } public static void printStudentInfo(String name, int age,int score){ System.out.println("姓名：" + name + "年龄" + age +"成绩" + score); }*/

package cn.tedu.day05;

/**

成员变量和局部变量1、在类中的位置不同成员变量：类中，方法外局部变量：方法中或者方法的声明上(形参)2、在内存中成员变量：堆内存中局部变量：栈内存中3、初始化成员变量：有默认值局部变量：没有默认值，必须先进性声明，后进行初始化4、生命周期成员变量：随着对象的创建存在，对象消失而消失局部变量：随着方法的调用存在，方法调用完毕后消失@author Administrator * */

public class VariableTest {

//x成员变量 static int x; public static void main(String[] args) { x = 66; printInfo(); System.out.println(x + "===");// } public static void printInfo(){ x = 76; int y = 5; System.out.println(x + "-------"); System.out.println(x); System.out.println(y); }

}

画布：乌龟

package cn.tedu.day05;

import javax.swing.JFrame;

public class WuguiMain extends JFrame {

public WuguiMain (){

this.setSize(1400,800); this.setTitle("123"); this.setDefaultCloseOperation(this.EXIT_ON_CLOSE); this.setLocationRelativeTo(null); WuguiPanel tj = new WuguiPanel();//创建对象 this.add(tj);//装载到窗体 this.setVisible(true); this.addMouseListener(tj); tj.addMouseListener(tj);//监听

}

/主函数程序入口/

public static void main(String[] args) { new WuguiMain (); }

}

package cn.tedu.day05;

import java.awt.Color;

import java.awt.Font;

import java.awt.Graphics;

import java.awt.event.MouseEvent;

import java.awt.event.MouseListener;

import javax.swing.JPanel;

public class WuguiPanel extends JPanel implements Runnable,MouseListener{

int x = 300; int y = 200;//乌龟的初始位置 int k1 = 300, t1 = 200; int k2 = 300, t2 = 200; int k3 = 300, t3 = 200; int k4 = 300, t4 = 200; //写一个数组 int[] a = new int[200];//x坐标 int[] b = new int[200];//y坐标 public WuguiPanel(){//构造方法 this.setBackground(Color.CYAN); //产生水波纹 for(int i = 0; i < a.length; i++){ a[i] = (int) (Math.random()*1400); b[i] = (int) (Math.random()*800); } //线程 Thread t = new Thread(this); t.start(); }

public void paint(Graphics g){

super.paint(g); g.setColor(Color.BLUE); for(int i = 0; i < a.length; i++){ g.drawString("~", a[i], b[i]); } //设置颜色 g.setColor(Color.GREEN); g.fillOval(x, y,70, 100); //画眼 g.setColor(Color.BLACK); g.fillOval(x + 10, y + 30, 10, 15); g.fillOval(x + 50, y + 30, 10, 15); //画嘴 g.setColor(Color.RED); g.fillOval(x + 30, y, 8, 6); g.setColor(Color.ORANGE); //ctrl+alt+下健 g.fillOval(k1 - 75, t1 + 70, 60, 70);//左上脚 g.fillOval(k2 + 75, t2 + 70, 60, 70);//左下 g.fillOval(k3 - 75, t3 + 235, 60, 70);//左上 g.fillOval(k4 + 75, t4 + 235, 60, 70);//右下 //画壳 g.setColor(Color.GREEN); g.fillOval(x - 66, y + 69, 200, 230); //字 g.setColor(Color.RED); Font font = new Font(Font.DIALOG,Font.BOLD,30); g.setFont(font); g.drawString("1111",x - 25,y + 175 );

}

public static void main(String[] args) { } @Override public void run() {

while(true){

x++; if(x >= 1440){ x = 0 ; } k1++; if(k1 >= 1440){ k1 = 0 ; } k2++; if(k2 >= 1440){ k2 = 0 ; } k3++; if(k3 >= 1440){ k3 = 0 ; } k4++; if(k4 >= 1440){ k4 = 0 ; } for (int i = 0; i < a.length; i++) { a[i]--; if (a[i] < 0) { a[i] = 1400; } } repaint();//重绘调用paint方法 //线程的睡眠 try { Thread.sleep(10); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); }

}

} @Override public void mouseClicked(MouseEvent e) { // TODO Auto-generated method stub } @Override public void mousePressed(MouseEvent e) { // TODO Auto-generated method stub

// System.out.println(“启动了”);

x = e.getX(); y = e.getY(); k1 = e.getX(); t1 = e.getY(); k2 = e.getX(); t2 = e.getY(); k3 = e.getX(); t3 = e.getY(); k4 = e.getX(); t4 = e.getY(); repaint(); } @Override public void mouseReleased(MouseEvent e) { // TODO Auto-generated method stub } @Override public void mouseEntered(MouseEvent e) { // TODO Auto-generated method stub

//

} @Override public void mouseExited(MouseEvent e) { // TODO Auto-generated method stub }

}