验证码是一种区分用户是计算机还是人的公共全自动程序；可以防止恶意破解密码、刷票、论坛灌水、刷页、恶意注册、登录。
直接上代码
public static void main(String[] args) throws IOException {
Random rand = new Random();
//画板
BufferedImage i = new BufferedImage(200, 100, 1);
//画笔
var m = i.createGraphics();
//平滑度
m.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_GASP);
m.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
m.setRenderingHint(RenderingHints.KEY_STROKE_CONTROL, RenderingHints.VALUE_STROKE_DEFAULT);
m.setColor(new Color(rand.nextInt(255), rand.nextInt(255), rand.nextInt(255), rand.nextInt(150, 200)));
m.fillRect(0, 0, 200, 100);
Font font = new Font("宋体", Font.BOLD, 50);
m.setFont(font);
var fm = m.getFontMetrics(font);
//验证字符
String setter = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
StringBuilder sb = new StringBuilder();
//生成随机验证码
for (int j = 0; j < 6; j++) {
//随机颜色
m.setColor(new Color(rand.nextInt(120, 255), rand.nextInt(120, 255), rand.nextInt(120, 255), 255));
int x = j * 30 + 10;
//验证字符位置
int y1 = i.getHeight() / 2 + (fm.getAscent() - fm.getDescent()) / 2 - fm.getHeight() / 3;
int y2 = i.getHeight() / 2 + (fm.getAscent() - fm.getDescent()) / 2 + fm.getHeight() / 3;
int a = rand.nextInt(setter.length());
font.deriveFont(rand.nextInt(45, 55));
var s = setter.substring(a, a + 1);
m.drawString(s, x, rand.nextInt(y1, y2));
sb.append(s);
}
//验证码干扰
for (int j = 0; j < 10; j++) {
m.setColor(new Color(rand.nextInt(255), rand.nextInt(255), rand.nextInt(255), rand.nextInt(50, 120)));
int a = rand.nextInt(setter.length());
var s = setter.substring(a, a + 1);
m.drawString(s, rand.nextInt(10, 190), rand.nextInt(10, 90));
}
for (int j = 0; j < 3; j++) {
m.setColor(new Color(rand.nextInt(255), rand.nextInt(255), rand.nextInt(255), rand.nextInt(100, 200)));
m.setStroke(new BasicStroke(3));
m.drawLine(rand.nextInt(10, 20), rand.nextInt(20, 90), rand.nextInt(170, 190), rand.nextInt(20, 90));
}
//曲线干扰
Point[] points = {new Point(0, 0), new Point(0, rand.nextInt(100)), new Point(200, rand.nextInt(100))
};
GeneralPath path = new GeneralPath();
path.moveTo(points[0].x, points[0].y);
for (int i2 = 0; i2 < points.length - 1; ++i2) {
Point sp = points[i2];
Point ep = points[i2 + 1];
Point c1 = new Point((sp.x + ep.x) / 2, sp.y);
Point c2 = new Point((sp.x + ep.x) / 2, ep.y);
path.curveTo(c1.x, c1.y, c2.x, c2.y, ep.x, ep.y);
}
// g.draw(path);
for (int n = 0; n <= 355; n += 10) {
// g.drawArc(100, 200, 600, 300, n, 5);
}
int yy = 100;// y
int hh = 100;// 高度
int aa = 200;//
// x
for (int x = 10; x < 200; x += 15) {
int y = (int) (yy + hh * Math.sin(x * Math.PI / aa));
//g.drawLine(x, (int) y, x, (int) y);
m.fillOval(x, y, 6, 6);
}
m.dispose();
ImageIO.write(i, "jpg", new File("yanzheng.jpg"));
Runtime.getRuntime().exec("cmd /k start yanzheng.jpg");
}
