验证码
1.java类MakeCert 生成验证码
package com.certCode;
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.util.Random;
import javax.imageio.ImageIO;
/**
* 生成验证图片
* @author 郑平
*
*/
public class MakeCert {
//图片验证可能出现的字符
private char mapTable[]={
'a','b','c','d','e','f',
'g','h','i','j','k','l',
'm','n','o','p','q','r',
's','t','u','v','w','x',
'y','z','0','1','2','3',
'4','5','6','7','8','9'};
/**
* 功能:生成彩色验证码图片
* 参数width为生成图片的宽度,参数height为生成图片的高度,参数os为页面的输出流
*/
public String getCertcode(int width,int height,OutputStream os) {
if(width<=0){
width = 60;
}
if(height<=0){
height = 20;
}
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
//获取图形上下文
Graphics g = image.getGraphics();
//设置 背景颜色
g.setColor(new Color(0xDCDCDC));
g.fillRect(0, 0, width, height);
//画边框
g.setColor(Color.black);
g.drawRect(0, 0, width-1, height-1);
String strEnsure = "";
for(int i=0;i<4;i++){
//随机产生的验证码
strEnsure += mapTable[(int)(mapTable.length*Math.random())];
}
System.out.println("strEnsure:"+strEnsure);
//将验证码显示到图片上
g.setFont(new Font("Atlantic Inline",Font.PLAIN,18));
String str = strEnsure.substring(0, 1);
g.drawString(str, 8, 17);
str = strEnsure.substring(1,2);
g.drawString(str,20,15);
str = strEnsure.substring(2,3);
g.drawString(str,35,18);
str = strEnsure.substring(3,4);
g.drawString(str,45,15);
// 随机产生10个干扰点
Random r = new Random();
for(int i =0;i<10;i++){
int x = r.nextInt(width);
int y = r.nextInt(height);
g.drawOval(x, y, 1, 1);
}
// 释放图形上下文
g.dispose();
try {
ImageIO.write(image, "JPEG", os);
} catch (IOException e) {
// TODO Auto-generated catch block'
return "";
}
return strEnsure;
}
}
2.makeCert.jsp jsp调用java类得到验证码 将生成的验证码存在session里面
<%@ page contentType="image/jpeg; charset=gb2312"
pageEncoding="utf-8"%>
验证
<%
String str=image.getCertcode(0,0,response.getOutputStream());
session.setAttribute("certCode", str);
out.clear();
out = pageContext.pushBody();
%>
3.login.jsp 登录界面jsp
<%@ page language="java" contentType="text/html; charset=gb2312"
pageEncoding="utf-8"%>
登录