regservlet.java

一套网上书店系统采用JAVABEAN+SERVLET+JSP

package cn.dang.servlet;

import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Date;
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.JPEGEncodeParam;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

public class RegServlet 

extends HttpServlet { 

//Process the HTTP Get request 

  public void doGet(HttpServletRequest request, HttpServletResponse response) throws 

      ServletException, IOException { 

    response.setContentType("utf-8"); 

    response.setContentType("image/jpeg");  //必须设置ContentType为image/jpeg 

    int length = 4;      //设置默认生成4个数字 

    Date d = new Date(); 

    long lseed = d.getTime(); 

    java.util.Random r = new Random(lseed);   //设置随机种子 

    if (request.getParameter("length") != null) { 

      try { 

       length = Integer.parseInt(request.getParameter("length")); 

      } 

      catch (NumberFormatException e) { 

      } 

    } 

    StringBuffer str = new StringBuffer(); 

    for (int i = 0; i <length; i++) { 

      str.append(r.nextInt(9));        //生成随机数字 

} 

//可以在此加入保存验证码的代码 

    //创建内存图像 

    BufferedImage bi = new BufferedImage(40, 16, BufferedImage.TYPE_INT_RGB); 

    Graphics2D g = bi.createGraphics(); 

    g.clearRect(0, 0, 16, 40); 

    g.setColor(Color.green.CYAN); 

    g.drawString(str.toString(), 4, 12); 

    try { 

      //使用JPEG编码，输出到response的输出流 

      JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(response. 

      getOutputStream()); 

      JPEGEncodeParam param = encoder.getDefaultJPEGEncodeParam(bi); 

      param.setQuality(1.0f, false); 

      encoder.setJPEGEncodeParam(param); 

      encoder.encode(bi); 

    } 

    catch (Exception ex) { 

    

    } 

  }    

}