servlet
import java.awt.Color;
import java.awt.Font;
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.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
public class ImageServlet extends HttpServlet 
{
private static final long serialVersionUID = 1L;
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
int width=150;//驗(yàn)證碼圖片寬度
int height=60;//驗(yàn)證碼圖片高度
BufferedImage image=new BufferedImage(width,height,BufferedImage.TYPE_3BYTE_BGR);
Graphics g=image.getGraphics();
Random random=new Random();//創(chuàng)建一個(gè)隨機(jī)類
g.setColor(getRandColor(200,250));//背景顏色要偏淡
g.fillRect(0, 0, width, height);//畫背景
g.setColor(getRandColor(0,255));//邊框顏色
g.drawRect(0, 0, width-1, height-1);//畫邊框
g.setColor(getRandColor(160,200));// 隨機(jī)產(chǎn)生5條干擾線，使圖象中的認(rèn)證碼不易被其它程序探測(cè)到
for(int i=0;i<8;i++){
int x=random.nextInt(width);
int y=random.nextInt(height);
int x1=random.nextInt(width);
int y1=random.nextInt(height);
g.drawLine(x, y, x1, y1);
}
g.setColor(getRandColor(160,200));// 隨機(jī)產(chǎn)生100點(diǎn)，使圖象中的認(rèn)證碼不易被其它程序探測(cè)到
for(int i=0;i<100;i++){
int x=random.nextInt(width);
int y=random.nextInt(height);
g.drawLine(x, y, x, y);
}
Font font = new Font("Times New Roman", Font.ITALIC,38); // 創(chuàng)建字體，字體的大小應(yīng)該根據(jù)圖片的高度來(lái)定。
g.setFont(font);//設(shè)置字體
int length = 6; // 設(shè)置默認(rèn)生成4個(gè)驗(yàn)證碼
String s="abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"; // 設(shè)置備選驗(yàn)證碼:包括"a-z"和數(shù)字"0-9"
String sRand="";
// 用隨機(jī)產(chǎn)生的顏色將驗(yàn)證碼繪制到圖像中。
// 生成隨機(jī)顏色(因?yàn)槭亲銮熬?，所以偏?
//調(diào)用函數(shù)出來(lái)的顏色相同，可能是因?yàn)榉N子太接近，所以只能直接生成
g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));
for(int i=0;i<length;i++){
String ch=String .valueOf(s.charAt(random.nextInt(s.length())));
sRand+=ch;
g.drawString(ch, 22*i+12, (random.nextInt(5)-2)*i+40);
}
//將生成的字符串存儲(chǔ)在session中
HttpSession session=request.getSession();
session.setAttribute("checkCode", sRand);
g.dispose();//圖像生效
//禁止圖像緩存
response.setHeader("Pragma", "No-cache");
response.setHeader("Cache-Control", "no-cache");
response.setDateHeader("Expires", 0);
response.setContentType("image/jpeg");
//創(chuàng)建二進(jìn)制的輸出流
ServletOutputStream sos=response.getOutputStream();
// 將圖像輸出到Servlet輸出流中。
ImageIO.write(image, "jpeg", sos);
sos.flush();
sos.close();
}
public Color getRandColor(int lower,int upper){
Random random = new Random();
if(upper>255)
upper=255;
if(upper<1)
upper=1;
if(lower<1)
lower=1;
if(lower>255)
lower=255;
int r=lower+random.nextInt(upper-lower);
int g=lower+random.nextInt(upper-lower);
int b=lower+random.nextInt(upper-lower);
return new Color(r,g,b);
}
}
xml配置
<servlet>
<servlet-name>ImageServlet</servlet-name>
<servlet-class>ImageServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>ImageServlet</servlet-name>
<url-pattern>/ImageServlet</url-pattern>
</servlet-mapping>
HTML
<%@ page language="java" pageEncoding="gbk"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>驗(yàn)證碼</title>
</head>
<body>
<%
try{
String code=request.getParameter("code");
String random=(String)session.getAttribute("checkCode");
if(code.equals(random))
{
out.print("驗(yàn)證成功");
}
}catch(Exception e){}
%>
<form action="" method="post">
<img align="middle" src="ImageServlet" width="80"/>
<input type="text" name="code"/>
<input type="submit" value="go"/>
</form>
</body>
</html>
驗(yàn)證碼搜藏