How to make JSP random verification pictures
- 2021-07-22 10:57:46
- OfStack
This site has compiled an article about imitating Tencent's random verification pictures. Let's go directly to the code below! 1 Java class and 1 JSP page.
Java class code:
The following is a quote clip of JSP imitating Tencent's random verification picture:
package icewee.image;
import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.geom.Line2D;
import java.awt.image.BufferedImage;
import java.util.Random;
public class TokenUtil {
private static final String base = "23456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefhijklmnpqrstuvwxyz";
private static final int length = base.length();
public static BufferedImage createTokenImage(int width, int height,
String randomCode) {
BufferedImage image = new BufferedImage(width, height,
BufferedImage.TYPE_INT_RGB);
Graphics2D g = image.createGraphics();
Random random = new Random();
g.setColor(new Color(230, 230, 250)); // Set the background color
g.fillRect(0, 0, width, height); // Fill the background
g.setColor(Color.BLACK);
// Draw Edge
g.drawRect(-1, -1, width + 1, height + 1);
g.setColor(Color.GRAY);
// Set fonts , Randomly select fonts , Temporary setting 8 Fonts
Font font = new Font((new String[] { "Arial", "Arial Black",
"Arial Italic", "Courier New", "Courier New Bold Italic",
"Courier New Italic", "Franklin Gothic Medium",
"Franklin Gothic Medium Italic" })[random.nextInt(8)],
Font.PLAIN, 30);
// g.setStroke(new BasicStroke((float)(Math.random()),
// BasicStroke.CAP_BUTT, BasicStroke.JOIN_BEVEL));
g.setFont(font);
// Define font color range
int red = random.nextInt(160), green = random.nextInt(50), blue = random
.nextInt(50);
// Definition 1 Interval sum of non-interference lines 1 Starting position
int nor = random.nextInt(50), rsta = random.nextInt(131);
// Drawing interference sine curve M: Horizontal folding of curve , D:Y Axial constant V:X Axial focal length
int M = random.nextInt(15) + 5, D = random.nextInt(23) + 15, V = random
.nextInt(5) + 1;
double x = 0.0;
double y = M * Math.sin(Math.toRadians(V * x)) + D;
double px, py;
for (int i = 0; i < 131; i++) {
px = x + 1;
py = M * Math.sin(Math.toRadians(V * px)) + D;
if (rsta < i && i < (rsta + nor))
g.setColor(new Color(230, 230, 250));
else
g.setColor(new Color(red, green, blue));
// Randomly set pixel broadband ( Line width )
g.setStroke(new BasicStroke((float) (Math.random() + 1.5f)));
g.draw(new Line2D.Double(x, y, px, py));
x = px;
y = py;
}
char[] codes = randomCode.toCharArray();
for (int i = 0; i < codes.length; i++) {
// Rotating figure
int degree = (random.nextInt(20) - 10) % 360;
double ang = degree * 0.0174532925; // Turn an angle into a radian
g.rotate(ang, width / 2, height / 2);
g.setColor(new Color(red, green, blue));
g.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
int gr = random.nextInt(8);
g.drawString(String.valueOf(codes[i]), 24 * i + 10 + gr, 38);
}
g.dispose();
return image;
}
public static String createRandomCode(int size, int width, int height) {
StringBuffer randomCode = new StringBuffer();
for (int i = 0; i < size; i++) {
Random random = new Random();
int start = random.nextInt(length);
String strRand = base.substring(start, start + 1);
randomCode.append(strRand);
}
return randomCode.toString();
}
}
JSP page:
The following is a reference fragment of JSP imitating Tencent's random verification picture code:
<%@ page contentType="image/jpeg" pageEncoding="GBK"%>
<%@ page import="java.awt.image.BufferedImage" %>
<%@page import="javax.imageio.ImageIO" %>
<%@ page import="com.icesoft.image.TokenUtil" %>
<%
// Setting the page not to cache
response.setHeader("Pragma", "No-cache");
response.setHeader("Cache-Control", "no-cache");
response.setDateHeader("Expires", 0);
int width = 120, height = 50;
String randomCode = TokenUtil.createRandomCode(4, width, height);
System.out.println(" Generated random code: " + randomCode);
BufferedImage image = TokenUtil.createTokenImage(width, height, randomCode);
ImageIO.write(image, "JPEG", response.getOutputStream());
response.flushBuffer();
out.clear();
out = pageContext.pushBody();
%>
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