写一个随机生成验证码的类(Java)

首先创建一个类的成员变量：

		// w，h为图片的宽高
		private int w= 70;
		private int h= 35;
		//创建一个Random类的对象
		private Random r = new Random();
		//字体数组
		private String[] fontName = {"宋体","华文楷体","黑体","微软雅黑","楷体_GB_2312"};
		//可选字符
		private String codes = "23456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
		//背景色
		private Color bgColor = new Color(255, 255, 255);
		//验证码字符串
		private String text;

随机获取字体的颜色：

private Color randomColor() {
			//选取150以下的避免看不清
			int red = r.nextInt(150);
			int green = r.nextInt(150);
			int bule = r.nextInt(150);
			return new Color(red,green,bule);
		}

随机获取字体Font：

private Font randomFont() {
			int index = r.nextInt(fontName.length);
			String fontname = fontName[index];
			//获取随机的样式，0(无样式)，1(粗体)，2(斜体)，3(粗体斜体);
			int style = r.nextInt(4);
			//生成随机字号大小 范围在24 - 28,避免字体太小
			int size = r.nextInt(5) + 24;
			return new Font(fontname, style, size);
		}

画三条验证码的干扰线

private void drawLine (BufferedImage image) {
			//画三条
			int num = 3 ;
			//获取画笔
			Graphics2D g2 = (Graphics2D) image.getGraphics();
			for(int i = 0; i<num;i++) {
				//生成两个点的坐标，即4个值
				int x1 = r.nextInt(w);
				int y1 = r.nextInt(h);
				int x2 = r.nextInt(w);
				int y2 = r.nextInt(h);
				g2.setStroke(new BasicStroke(1.5F));
				//设置干扰线的颜色是蓝色
				g2.setColor(Color.BLUE);
				g2.drawLine(x1, y1, x2, y2);
			}
		}

随机获取字符：

private char randomChar() {
			//随机获取codes的索引
			int index = r.nextInt(codes.length());
			return codes.charAt(index);
		}

画图：

		private BufferedImage createImage() {
			BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
			Graphics2D g2 =(Graphics2D) image.getGraphics();
			g2.setColor(this.bgColor);
			g2.fillRect(0, 0, w,h);
			return image;
		}

获取验证码：

public BufferedImage getImage() {
			//创建图片缓冲区
			BufferedImage image = createImage();
			//得到绘制环境
			Graphics2D g2 = (Graphics2D) image.getGraphics();
			//用来装载生成的文本
			StringBuilder sb = new StringBuilder();
			//循环4次每次生成一个字符
			for(int i =0;i<4;i++) {
				//随机生成一个字母
				String s = randomChar()+"";
				sb.append(s);
				//设置当前字符的x轴坐标
				float x = i * 1.0F * w/4;
				g2.setFont(randomFont());
				g2.setColor(randomColor());
				g2.drawString(s, x, h-5);
			}
			this.text = sb.toString();
			//添加干扰线
			drawLine(image);
			return image;
		}

获取生成验证码的文本：

public String getText() {
			return text;
		}

保存图片到指定输出流：

		public static void output(BufferedImage image,OutputStream outputstream) throws IOException {
			ImageIO.write(image,"JPEG", outputstream);
		}

创建好之后直接调用这个类就可以生成随机的验证码；

	public static void main(String[] args) throws FileNotFoundException, IOException {
		Yanzhengma yzm = new Yanzhengma();
		BufferedImage image = yzm.getImage();
		Yanzhengma.output(image, new FileOutputStream("D:\\xxx.jpg"));
		String text =yzm.getText();
		Scanner sc = new Scanner(System.in);
		System.out.println("请输入验证码:");
		String test = sc.nextLine();
		if(text.equals(test)) {
			System.out.println("恭喜验证成功");
		}else {
			System.out.println("验证失败，请重新输入");
		}
	}