java仿Servlet生成验证码实例详解

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); }

最终实现效果图

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