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jsp页面验证码(完整实例)
阅读量:6719 次
发布时间:2019-06-25

本文共 4029 字,大约阅读时间需要 13 分钟。

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.
*/ public void destroy() { super.destroy(); // Just puts "destroy" string in log // Put your code here } /** * The doGet method of the servlet.
* * 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
* * 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.
* * @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

IdentityServlet
com.servlet.IdentityServlet
IdentityServlet
/servlet/IdentityServlet
index.jsp

 

3、WebRoot下新建一个html,展示验证码

Insert title here

 

 

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

 

转载于:https://www.cnblogs.com/Donnnnnn/p/6226034.html

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