个人认为效果还可以,并且比较简单生成的验证码的例子！！！！
java代码：
package com.trs.nfdaily.imgcode;
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;
public class MakeCertPic
{
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' };//验证码内容
public String getCertPic(int width, int height, OutputStream os)
{
if (width <= 0)
width = 60;
if (height <= 0)
height = 20;
BufferedImage image = new BufferedImage(width, height,
1);
Graphics g = image.getGraphics();
g.setColor(new Color(14474460));
g.fillRect(0, 0, width, height);
g.setColor(Color.black);
g.drawRect(0, 0, width - 1, height - 1);
String strEnsure = "";
for (int i = 0; i < 4; i++) {
strEnsure = strEnsure + this.mapTable[((int)(this.mapTable.length * java.lang.Math.random()))];
}
g.setColor(Color.black);
g.setFont(new Font("Atlantic Inline", 0, 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);
Random rand = new Random();
for (int i = 0; i < 10; i++) {
int x = rand.nextInt(width);
int y = rand.nextInt(height);
g.drawOval(x, y, 1, 1);
}
g.dispose();
try
{
ImageIO.write(image, "JPEG", os);
} catch (IOException e) {
return "";
}
return strEnsure;
}
}
jsp代码
imgCode.jsp
<%@page contentType="image/jpeg" %>
<jsp:useBean id="image" scope="page" class="com.trs.nfdaily.imgcode.MakeCertPic" />
<%
String str=image.getCertPic(0,0,response.getOutputStream());
// 将认证码存入SESSION
session.setAttribute("imgcode", str);
out.clear();
out = pageContext.pushBody();
%>
login.jsp
//验证码
function changeCode(){
document.getElementById("rc").src="imgCode.jsp?time="+new Date().getTime();
}
</tr>
<tr><td align="right" valign="top">验证码：</td><td><input name="imgcode" id="imgCode" width="15px" height="50px" class="write" ></td></tr>
<tr><td><div><img src="imgCode.jsp" id="rc" name="image" /> </td><td><a href="javaScript:changeCode()">看不清?点击更换</a></div></td></tr>
