验证码生成（java版本）

//该类生成验证按图片

package xtu.hl.vcode.utils;

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;

import javax.imageio.ImageIO;

public class VerifyCode {
private int w = 100;
private int h = 62;
private Random r = new Random();
private String[] fontNames = { "宋体", "华文楷体", "黑体", "微软雅黑", "楷体_GB2312" };
private String codes = "3456789abcdefghjkmnopqrstuvwxyABCDEFGHJKMNPQRSTUVWXY";
private Color bgColor = new Color(255, 255, 255);
private String text;

private Color randomColor() {
int red = r.nextInt(150);
int green = r.nextInt(150);
int blue = r.nextInt(150);
return new Color(red, green, blue);
}
private Font randomFont() {
int index = r.nextInt(fontNames.length);
String fontName = fontNames[index];
int style = r.nextInt(4);
int size = r.nextInt(5) + 24;
return new Font(fontName, style, size);
}
private void drawLine(BufferedImage image) {
int num = 3;
Graphics2D g2 = (Graphics2D) image.getGraphics();
for (int i = 0; i < num; i++) {
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));
g2.setColor(Color.BLUE);
g2.drawLine(x1, y1, x2, y2);
}
}
private char randomChar() {
int index = r.nextInt(codes.length());
return codes.charAt(index);
}
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;
}
public BufferedImage getImage() {
BufferedImage image = createImage();
Graphics2D g2 = (Graphics2D) image.getGraphics();
StringBuilder sb = new StringBuilder();
for (int i = 0; i < 4; i++) {
String s = randomChar() + "";
sb.append(s);
float x = i * 1.0F * w / 4;
g2.setFont(randomFont());
g2.setColor(randomColor());
g2.drawString(s, x, h - 5);
}
this.text = sb.toString();
drawLine(image);
return image;
}

public String getText() {
return text;
}
public static void output(BufferedImage image, OutputStream out)
throws IOException {
ImageIO.write(image, "JPEG", out);
}
}

//该类保存验证码图片到session中，为验证做准备

package xtu.hl.vcode.servlet;

import java.awt.image.BufferedImage;
import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import xtu.hl.vcode.utils.VerifyCode;

public class VerifyCodeServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
VerifyCode vc = new VerifyCode();
BufferedImage image = vc.getImage();//获取一次性验证码图片
VerifyCode.output(image, response.getOutputStream());//把图片写到指定流中
// 把文本保存到session中，为LoginServlet验证做准备
request.getSession().setAttribute("vCode", vc.getText());
}
}