Servlet生成验证码图片2

zeroline — Mon, 03 Jan 2011 12:51:00 GMT

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.Random;

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

import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

public class Image extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {
  response.setContentType("image/jpeg");
  OutputStream out = response.getOutputStream();
  response.setHeader("Pragma","No-cache");
  response.setHeader("Cache-Control","no-cache");
  response.setDateHeader("Expires", 0);
  int width = 60, height = 20;
  BufferedImage image = new BufferedImage(width, height,
    BufferedImage.TYPE_INT_RGB);
  // 获取图形上下文
  Graphics g = image.getGraphics();
  // 生成随机类
  Random random = new Random();
  // 设定背景色
  g.setColor(getRandColor(200, 250));
  g.fillRect(0, 0, width, height);
  // 设定字体
  g.setFont(new Font("Times New Roman", Font.PLAIN, 18));
  // 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到
  g.setColor(getRandColor(180, 200));
  for (int i = 0; i < 155; 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);
  }
  // 取随机产生的认证码(4位数字)
  String sRand =setRandValue(request);
  if(sRand!=null)
  for (int i = 0; i < sRand.length(); i++) {
   g.setColor(new Color(20 + random.nextInt(200), 20 + random
     .nextInt(200), 20 + random.nextInt(200)));
   // 调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
   g.drawString(sRand.charAt(i) + "", 13 * i + 6, 16);
  }

  JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
  encoder.encode(image);
  // 图象生效
  g.dispose();
  // 输出图象到页面
  // ImageIO.write(image, "JPG", response.getOutputStream());
  out.flush();
  out.close();
}

Color getRandColor(int fc, int bc) {// 给定范围获得随机颜色
  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);
}
//48-57对应0-9;65-90对应A-Z;97-122对应a-z;
String setRandValue(HttpServletRequest request) {
  Random random = new Random();
  String sRand = "";
  //这里是生成验证码的位数
  for (int i = 0; i < 4; i++) {
   char c = 0;
   int k = random.nextInt(3);
   switch (k) {
   case 0:
    c = (char) (random.nextInt(10) + 48);
    break;
   case 1:
    c = (char) (random.nextInt(26) + 65);
    break;
   case 2:
    c = (char) (random.nextInt(26) + 97);
   }
   sRand += c;
  }
  request.getSession().setAttribute("rands", sRand);
  return sRand;
}
}

zeroline 2011-01-03 20:51 发表评论

Servlet生成验证码图片

zeroline — Sun, 21 Nov 2010 04:46:00 GMT

import java.awt.Color;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;

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

import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

public class ImageServlet extends HttpServlet {

    public void service(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        // 设置响应类型
        response.setContentType("image/jpeg");
        // 图片的内存映像
        BufferedImage image = new BufferedImage(50, 20,BufferedImage.TYPE_INT_RGB);
        // 获得画笔对象
        Random r = new Random();
        Graphics g = image.getGraphics();
        g.setColor(new Color(r.nextInt(255), r.nextInt(255), r.nextInt(255)));
        g.fillRect(0, 0, 50, 20);
        g.setColor(new Color(0,0,0));
        String number = String.valueOf(r.nextInt(99999));
        g.drawString(number, 5, 15);

        // 压缩成jpeg格式
        OutputStream os = response.getOutputStream();

        JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(os);

        // 把BufferedImage对象中的图像信息编码后
        // 向创建该对象(encoder)时指定的输出流输出
        encoder.encode(image);

    }

}

zeroline 2010-11-21 12:46 发表评论

BlogJava-ZeroLine-随笔分类-Servlet/JSP

Servlet生成验证码图片2

Servlet生成验证码图片