关于线程

    

                 线程，学了挺久了。我发现我不会写总结这种东西。

 

                 好吧，我又词穷了。不知道该怎么写了。先打开eclipse看看。先说说我对线程的理解把。

 

                我觉得线程就是好几条流水线在一起工作，能提高工作效率和空间利用率。就像一个工厂，如果只用一条流水线，那每天生产的鞋子估计少得可怜，利润应该也不怎么样，这样的工厂应该关门了。但是如果一个工厂有好多条流水线，同时生产好多鞋子，那就可以挣好多钱，可以在这个行业有很强的竞争力。程序也是一样。一个只能单条路走下去的程序只能用来当教材。多条路一起走的程序才是有效率的程序。

 

                放个简单的小球程序把，小球还不是立体的、、

 

import java.awt.BorderLayout;
import java.awt.FlowLayout;
import java.awt.Graphics;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class ThreadFrame extends JFrame{

	
	public static void main(String[] args) {
		ThreadFrame tf = new ThreadFrame();
		tf.init();
	}
	public void init(){
		
		//设置属性
		this.setTitle("弹球");
		this.setSize(1000,600);
		this.setLocationRelativeTo(null);
		this.setDefaultCloseOperation(3);
	//	this.setLayout(new FlowLayout());
		
		//实例化一个按钮
		JButton jbu1 = new JButton("发射");
		this.add(jbu1,BorderLayout.NORTH);
		JPanel jpa=new JPanel();
		this.add(jpa,BorderLayout.CENTER);
		//BallListener bl = new BallListener(jpa, ball);
		//设置可见
		this.setVisible(true);
		
		Graphics g = this.getGraphics();
		
		BallThread  ball=new BallThread(jpa);
	//	ball.start();
		BallListener tl = new BallListener(jpa,ball);
		jbu1.addActionListener(tl);
		
		
	}

}

 

import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.BitSet;

import javax.swing.JPanel;

public class BallListener implements ActionListener{

	private Graphics g;
	private BallThread ball;
	private JPanel jpa;
	//构造方法
	public BallListener(JPanel jpa,BallThread ball){
		this.jpa=jpa;
		this.g=jpa.getGraphics();
		this.ball=ball;
	}
	
	public void actionPerformed(ActionEvent e) {
		
		BallThread bt =new BallThread(jpa);
		bt.start();
	}
	
	
}

 

import java.awt.Color;
import java.awt.Graphics;
import java.util.Random;

import javax.swing.JPanel;

public class BallThread extends Thread{
		
	//定义四个方向的常量
	public static final int UP=1;
	public static final int DOWN=2;
	public static final int LEFT=3;
	public static final int RIGHT=4;
	
	//球的半径
	private int r;
	//球的颜色
	private Color color;
	private int c1,c2,c3;
	//x和y方向的速度
	private int xSpeed;
	private int ySpeed;
	
	//运动的方向
	private int xDirection = RIGHT;
	private int yDirection = DOWN;
	//当前球的位置
	private int x,y;
	//最后球的位置
	//private int lastX,lastY;
	
	private Graphics g;
	private JPanel jpa;
	//构造方法
	public BallThread(JPanel jpa) {
		this.jpa=jpa;
		this.g=jpa.getGraphics();
		
	}
	
	public void run(){
		init();
		while(true){
			try
		{
				sleep(50);
		}
		catch(InterruptedException e){
			e.printStackTrace();
		}
			
		clear();
		move();
		draw();
			}
	}
	public void init(){
		
		Random random = new Random();
		xSpeed=2+random.nextInt(5);
		ySpeed=2+random.nextInt(5);
		r=20+random.nextInt(20);
		c1=random.nextInt(256);
		c2=random.nextInt(256);
		c3=random.nextInt(256);
		color=new Color(random.nextInt(256),random.nextInt(256),random.nextInt(256));
		System.out.print(random.nextInt(256));
	}
	public void move(){
		
		switch(xDirection){
		
		case LEFT:
			x-=xSpeed;
			break;
		case RIGHT:
			x+=xSpeed;
		}
		switch (yDirection) {
		case UP:
			y-=ySpeed;
			break;
		case DOWN:
			y+=ySpeed;
			break;
		}
		
		if(x<=0){
			xDirection=RIGHT;
		}
		if(x+2*r>=jpa.getWidth()){
			xDirection=LEFT;
		}
		if(y<=0){
			yDirection=DOWN;
		}
		if(y+2*r>=jpa.getHeight()){
			yDirection=UP;
		}
		
	}
	
	private void draw(){
		g.setColor(color);
		g.fillOval(x, y, 2*r, 2*r);	
	}
	private void clear() {
		g.setColor(jpa.getBackground());
		g.fillOval(x, y, 2*r, 2*r);
	}
}