• Java生成验证码图片的程序


        package test;
        import java.awt.Color;
        import java.awt.Font;
        import java.awt.Graphics;
        import java.awt.image.BufferedImage;
        import java.io.OutputStream;
        import java.util.Random;
    
        import javax.imageio.ImageIO;
        import javax.servlet.http.HttpServlet;
        import javax.servlet.http.HttpServletRequest;
        import javax.servlet.http.HttpServletResponse;
    
    
        public class ImageGenerator extends HttpServlet {
          /** *//**
           *
           */
          private static final long serialVersionUID = -3938318741402322164L;
    
          private static Color getRandColor(int fc, int bc) {
            Random random = new Random();
            if (fc > 255)
              fc = 255;
            if (bc > 255)
              bc = 255;
            int r = fc + random.nextInt(bc - fc);
            int g = fc + random.nextInt(bc - fc);
            int b = fc + random.nextInt(bc - fc);
            return new Color(r, g, b);
          }
    
          private static String charsLong = "23456789abcdefghjklmnpqrstuvwxyzABCDEFGHIJKLMNPQRSTUVWXYZ";
    
          private static String charsShort = "0123456789";
    
          private static String chars = charsLong;
    
          @Override
          public void doGet(HttpServletRequest request, HttpServletResponse response) {
            try {
              int charsLength = chars.length();
    
              response.setHeader("Pragma", "No-cache");
              response.setHeader("Cache-Control", "no-cache");
              response.setDateHeader("Expires", 0);
    
              int width = 70, height = 20;
              BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
    
              Graphics g = image.getGraphics();
    
              Random random = new Random();
    
              g.setColor(getRandColor(200, 250));
              g.fillRect(0, 0, width, height);
    
              g.setFont(new Font("Times New Roman", Font.ITALIC, height));
    
              g.setColor(getRandColor(160, 200));
              for (int i = 0; i < 35; i++) {
                int x = random.nextInt(width);
                int y = random.nextInt(height);
                int xl = random.nextInt(12);
                int yl = random.nextInt(12);
                g.drawLine(x, y, x + xl, y + yl);
              }
    
              StringBuilder sRand = new StringBuilder();
              String[] fontNames = { "Times New Roman", "Arial", "Book antiqua", "" };
    
              for (int i = 0; i < 4; i++) {
                g.setFont(new Font(fontNames[random.nextInt(3)], Font.ITALIC, height));
                char rand = chars.charAt(random.nextInt(charsLength));
                sRand.append(rand);
    
                g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));
                g.drawString(String.valueOf(rand), 16 * i + random.nextInt(6) + 3, height - random.nextInt(4));
              }
    
              g.setColor(getRandColor(160, 200));
              for (int i = 0; i < 30; i++) {
                int x = random.nextInt(width);
                int y = random.nextInt(height);
                int xl = random.nextInt(width);
                int yl = random.nextInt(width);
                g.drawLine(x, y, x + xl, y + yl);
              }
    
              request.getSession().setAttribute("Login_Image_Code", sRand.toString());
    
              g.dispose();
    
              try {
                Thread.sleep(100);
              } catch (Exception ex) {
              }
              OutputStream os = response.getOutputStream();
              ImageIO.write(image, "JPEG", os);
              os.flush();
              os.close();
            } catch (Exception ex) {
    
            }
          }
        }
    
     
    
        修改 web.xml
    
     
    
        <servlet>
                <servlet-name>imageGenerator</servlet-name>
                <servlet-class>test.ImageGenerator</servlet-class>
            </servlet>
            <servlet-mapping>
                <servlet-name>imageGenerator</servlet-name>
                <url-pattern>/image.jsp</url-pattern>
            </servlet-mapping>

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  • 原文地址:https://www.cnblogs.com/jdluojing/p/3212450.html
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