纯servlet实现验证码

来源：互联网发布：mac怎么查看激活时间编辑：程序博客网时间：2024/04/27 15:26

package com.java.checkcode;

import java.awt.Color;

import java.awt.Graphics;

import java.awt.image.BufferedImage;

import java.io.IOException;

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;

public class checkcode extends HttpServlet {

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

BufferedImage bi=new BufferedImage(68,22,BufferedImage.TYPE_INT_RGB);//第一个参数图片的长度，第二个图片的高度，第三个常量是图像类型。

Graphics g=bi.getGraphics();

g.setColor(new Color(150,200,245));

g.fillRect(0,0,68,22);

char[] ch="ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789".toCharArray();

Random r=new Random();

int len=ch.length,index;

StringBuffer sb=new StringBuffer();

for(int i=0;i<4;i++){

index=r.nextInt(len);

g.setColor(new Color(r.nextInt(255),r.nextInt(255),r.nextInt(255)));

g.drawString(ch[index]+"",i*15+3,18);

sb.append(ch[index]);

}

request.getSession().setAttribute("picCode",sb.toString());//把生成的数字放入session用于验证

ImageIO.write(bi,"JPEG",response.getOutputStream());

}

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

doGet(request, response);

}

jsp代码：

// 请输入验证码:

// 看不清楚

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