本文实例为大家分享了sp页面验证码的具体代码，供大家参考，具体内容如下
项目结构如下，MyEclipse中新建一个Web Project，取名servlet
1、src下new一个servlet类
package com.servlet;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Random;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
public class IdentityServlet extends HttpServlet {
public static final char[] chars={
'2','3','4','5','6','7','8','9','A'}
;
//自定义验证码池 public static Random random=new Random();
//随机数 public static String getRandomString(){
//获取6位随机数，放在图片里 StringBuffer buffer=new StringBuffer();
for(int i=0;
i<6;
i++){
buffer.append(chars[random.nextInt(chars.length)]);
}
return buffer.toString();
}
public static Color getRandomColor(){
//获取随机的颜色 return new Color(random.nextInt(255), random.nextInt(255), random.nextInt(255));
}
public static Color getReverseColor(Color c){
//返回某颜色的反色 return new Color(255 - c.getRed(), 255 - c.getGreen(), 255 - c.getBlue());
}
/** * Constructor of the object. */ public IdentityServlet() {
super();
}
/** * Destruction of the servlet. <br> */ public void destroy() {
super.destroy();
// Just puts "destroy" string in log // Put your code here }
/** * The doGet method of the servlet. <br> * * This method is called when a form has its tag value method equals to get. * * @param request the request send by the client to the server * @param response the response send by the server to the client * @throws ServletException if an error occurred * @throws IOException if an error occurred */ public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("image/jpeg");
//设置输出类型 String randomString = getRandomString();
//随机字符串 request.getSession(true).setAttribute("randomString", randomString);
//放到session里 int width=100;
//图片宽度 int height=30;
//图片高度 Color color=getRandomColor();
//随机颜色，用于背景色 Color reverse=getReverseColor(color);
//反色，用于前景色 //创建一个彩色图片 BufferedImage bi=new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
Graphics2D g=bi.createGraphics();
//绘图对象 g.setFont(new Font(Font.SANS_SERIF,Font.BOLD,16));
//设置字体 g.setColor(color);
//设置颜色 g.fillRect(0, 0, width, height);
//绘制背景 g.setColor(reverse);
g.drawString(randomString, 18, 20);
//绘制随机字符 for(int i=0,n=random.nextInt(100);
i<n;
i++){
//画最多100个噪音点 g.drawRect(random.nextInt(width), random.nextInt(height), 1, 1);
}
ServletOutputStream out= response.getOutputStream();
//转成JPEG格式 JPEGImageEncoder encoder=JPEGCodec.createJPEGEncoder(out);
//编码器 encoder.encode(bi);
//对图片进行编码 out.flush();
//输出到客户端 }
/** * The doPost method of the servlet. <br> * * This method is called when a form has its tag value method equals to post. * * @param request the request send by the client to the server * @param response the response send by the server to the client * @throws ServletException if an error occurred * @throws IOException if an error occurred */ public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
/** * Initialization of the servlet. <br> * * @throws ServletException if an error occurs */ public void init() throws ServletException {
// Put your code here }
}
2、web.xml，会自动生成servlet和servlet-mapping的配置
<?xml version="1.0" encoding="UTF-8"?><web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"> <display-name></display-name> <servlet> <servlet-name>IdentityServlet</servlet-name> <servlet-class>com.servlet.IdentityServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>IdentityServlet</servlet-name> <url-pattern>/servlet/IdentityServlet</url-pattern> </servlet-mapping> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list></web-app>
3、WebRoot下新建一个html，展示验证码
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html;
charset=UTF-8"><title>Insert title here</title><script type="text/javascript">function reloadImage(){
document.getElementById('btn').disabled=true;
document.getElementById('identity').src='servlet/IdentityServlet?ts='+new Date().getTime();
}
</script></head><body><img src="servlet/IdentityServlet" id="identity" onload="btn.disabled=false;
" /><input type=button value="换个图片" onclick="reloadImage()" id="btn"></body></html>
启动Tomcat，输入网址：http://localhost:8080/servlet/identity.html，效果如下：
点击‘换个图片'，会生成新的验证码。
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。
