彩色验证码

来源：互联网发布：数据库开发主要做什么编辑：程序博客网时间：2024/05/06 09:55

package test;//打包

//导入相关包
import javax.servlet.*;
import javax.servlet.http.*;
import java.awt.*;
import java.awt.image.*;
import java.util.*;
import javax.imageio.*;
import java.io.*;

public class validate extends HttpServlet
{

public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException ,IOException
{
  response.setContentType("image/jpeg");
  HttpSession session=request.getSession();
  // 在内存中创建图象
  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();

  // 设定背景色
  g.setColor(new Color(255,255,255));
  g.fillRect(0, 0, width, height);

  //画边框
  g.setColor(Color.black);
  g.drawRect(0,0,width-1,height-1);

  // 取随机产生的认证码(4位数字)
  Random now=new Random();
  int xx=now.nextInt();
  if(xx<0)
  xx=0-xx;
  String rand=xx+"";
   switch(rand.length())
  {
  case 1: rand = "000"+rand; break;
  case 2: rand = "00"+rand; break;
  case 3: rand = "0"+rand; break;
  default: rand = rand.substring(0,4); break;
  }

  // 将认证码存入SESSION
  session.setAttribute("validate",rand);

  // 将认证码显示到图象中
  g.setColor(Color.black);
  Integer tempNumber = new Integer(rand);
  String numberStr = tempNumber.toString();

  g.setFont(new Font("Atlantic Inline",Font.PLAIN,18));
  String Str = numberStr.substring(0,1);
  g.drawString(Str,8,17);

  Str = numberStr.substring(1,2);
  g.drawString(Str,20,15);
  Str = numberStr.substring(2,3);
  g.drawString(Str,35,18);

  Str = numberStr.substring(3,4);
  g.drawString(Str,45,15);

  // 随机产生88个干扰点，使图象中的认证码不易被其它程序探测到
  Random random = new Random();
  for (int i=0;i<20;i++)
  {
  int x = random.nextInt(width);
  int y = random.nextInt(height);
  g.drawOval(x,y,0,0);
  }

  // 图象生效
  g.dispose();

  // 输出图象到页面
  ImageIO.write(image, "JPEG", response.getOutputStream());

}

}