image.java用于产生彩色验证码,其代码如下:
package test;
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 Image {//验证码图片中可以出现的字符集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'};//生成彩色的验证码图片。width表示图片宽度;height表示图片高度。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,BufferedImage.TYPE_INT_BGR);//获取图形上下文Graphics g=image.getGraphics();//设置背景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);//随机产生认证码String strEnsure="";//产生4位认证码for(int i=0;i<4;i++){strEnsure+=mapTable[(int)(mapTable.length*Math.random())];}//将认证码显示到图像中g.setColor(Color.black);g.setFont(new Font("Atlantic Inine",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 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);}//释放图形上下文g.dispose();try{//输出图像到页面ImageIO.write(image, "JPEG", os);}catch(IOException e){return "";}return strEnsure; }
}
<html>
<body>
<form action="check.jsp" method="post">
用户名:<input type="text" name="username"/> <br>
密 码<input type="password" name="password"> <br>
验证码:<input type="text" name="certCode"/>
<%-- 调用image.jsp显示验证码图片--%>
<img src="image.jsp"> <br>
<input type="submit" value="确定"/>
</form>
</body>
</html>
image.jsp负责调用JavaBean显示验证码图片,以及将得到的string形式验证码放入session中。其代码如下:
<jsp:useBean id="image" scope="session" class="test.Image"/>
<%
//得到生成的验证码,并将验证码以图片方式输出
String str=image.getCertPic(0,0,response.getOutputStream());
//将认证码存入session
session.setAttribute("certCode",str);%>
check,jsp负责比对用户输入的验证码和图片显示的验证码是否一致,其代码如下:
<%
//得到用户输入的验证码
String certCode=request.getParameter("certCode");
//比对用户输入的验证码和生成的验证码是否相同
if(certCode.equals((String)session.getAttribute("certCode")))out.print("验证码输入正确");elseout.print("验证码输入错误");%>
运行index.jsp进入登陆界面,截图如下:
1.若输入正确的验证码,截图如下:
点击”确定“后跳转到check.jsp页面,显示输入验证码正确:
2.若输入错误的验证码,截图如下:
点击”确定“后跳转到check.jsp页面,显示输入验证码错误: