登陆页面的识别码

来源：互联网发布：还有什么算命的算法编辑：程序博客网时间：2024/05/29 03:20

package com.identity;

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

import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
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.JPEGImageDecoder;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

public class IdentityServlet extends HttpServlet {

   public static final char[]CHARS ={'2','3','4','5','6','7','8','9','A','B','C','D','E','F',
       'G','H','J','K','L','M','N','P','Q','R','S','T','U','V','W','X','Y','Z'};//不包括难以识别的字符和数字o 0,I 1

   public static Random random = new Random();//随机数

   //生成随机六位字符
   public static String getRandomString(){
       StringBuffer sb = new StringBuffer();
       for(int i=0;i<6;i++){
           sb.append(CHARS[random.nextInt(CHARS.length)]);
       }
       return sb.toString();
   }

   //生成颜色
   public static Color getColor(){
       return new Color(random.nextInt(50),random.nextInt(255),random.nextInt(50));
   }
   //反色
   public static Color getReverseColor(Color c){
       return new Color(255-c.getRed(),255-c.getGreen(),255-c.getBlue());
   }


   public void doGet(HttpServletRequest request, HttpServletResponse response)
           throws ServletException, IOException {

       response.setContentType("image/jpeg");
       //随机生成的字符串
       String randomString = getRandomString();
       request.getSession(true).setAttribute("randomString", randomString);

       int width = 100;
       int height = 30;
       //背景色
       Color color = getColor();
       //前景色
       Color reserver = getReverseColor(color);

       //创建一个彩色图片
       BufferedImage bi = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);

       //获得绘图对象
       Graphics2D g = bi.createGraphics();

       g.setFont(new Font(Font.SANS_SERIF ,Font.BOLD,16));//设置字体

       //设置背景色
       g.setColor(color);

       g.fillRect(0, 0, width, height);//绘制背景

       g.setColor(reserver);//设置前景色

       g.drawString(randomString, 18, 20);//绘制随机字符

//       for(int i=0, n =random.nextInt(100);i<n;i++){
//           g.drawRect(random.nextInt(width), random.nextInt(height), 1, 1);//最多点100个噪音点
//       }



       //转化成jpeg格式
       ServletOutputStream out = response.getOutputStream();

       JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);//获得编码器

       encoder.encode(bi);//对图片进行编码
       out.flush();//输出到客户端



   }

   public void doPost(HttpServletRequest request, HttpServletResponse response)
           throws ServletException, IOException {
       this.doGet(request, response);
   }

}

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