java仿Servlet生成验证码实例详解_JAVA教程

java仿Servlet生成验证码实例详解

2020-09-20 13:47Java之家 JAVA教程

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实现原理：使用BufferedImage对象的Graphics来进行绘制，然后输出成一张图片进行保存

实现代码及详解:

									public class validateCode{

									  private static Random rand = new Random();

									  public static void main(String[] args){

									    int val1 = rand.nextInt(9);

									    int val2 = rand.nextInt(9);

									    int val3 = rand.nextInt(9);

									    int val4 = rand.nextInt(9);

									    String val = val1 + " " + val2 + " " + val3 + " " + val4'

									    BufferedImage buf = drawImage(val);

									    //将最终的图片保存到D：//cheng.png下

									    ImageIO.write(buf,"png",new File("D://cheng.png");

									  }

									  public static BufferedImage drawImage(String code){

									    int height = 30;

									    int width = 60;

									    BufferedImage buf = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);

									    Graphics2D gs = buf.createGraphics();

									    gs.setBackground(Color.black);

									    gs.drawRect(0,0,width,height); 

									    //绘制随机干扰线

									    int total = 100;

									    drawRandLine(gs,total);

									    //绘制验证码

									    Font font = new Font("行楷",Font.BOLD,20);

									    gs.setFont(font);

									    gs.setColor(getRandColor(155,255));

									    gs.drawString(code,5,20);

									    return buf;

									  }

									  public static void drawRandLine(Graphics2D gs,int total){

									    for(int i=0; i<total; i++){

									      int x1 = rand.nextInt(width);

									      int x2 = rand.nextInt(width);

									      int y1 = rand.nextInt(height);

									      int y2 = rand.nextInt(height);

									      //设置随机颜色

									      gs.setColor(getRandColor(0,155));

									      gs.drawLine(x1,y1,x2,y2);

									    }  

									  }

									  public static Color getRandColor(int from,int to){

									    int r = from + rand.nextInt(to-from);

									    int g = from + rand.nextInt(to-from);

									    int b = from + rand.nextInt(to-from);

									    return new Color(r,g,b);  

									  }