jsp頁面驗證碼完整實例
本文實例為大家分享了sp頁面驗證碼的具體代碼,供大家參考,具體內(nèi)容如下
項目結(jié)構(gòu)如下,MyEclipse中新建一個Web Project,取名servlet
1、src下new一個servlet類
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'};//自定義驗證碼池 public static Random random=new Random(); //隨機(jī)數(shù) public static String getRandomString(){ //獲取6位隨機(jī)數(shù),放在圖片里 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(){ //獲取隨機(jī)的顏色 return new Color(random.nextInt(255), random.nextInt(255), random.nextInt(255)); } public static Color getReverseColor(Color c){ //返回某顏色的反色 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"); //設(shè)置輸出類型 String randomString = getRandomString(); //隨機(jī)字符串 request.getSession(true).setAttribute("randomString", randomString);//放到session里 int width=100; //圖片寬度 int height=30; //圖片高度 Color color=getRandomColor(); //隨機(jī)顏色,用于背景色 Color reverse=getReverseColor(color);//反色,用于前景色 //創(chuàng)建一個彩色圖片 BufferedImage bi=new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); Graphics2D g=bi.createGraphics(); //繪圖對象 g.setFont(new Font(Font.SANS_SERIF,Font.BOLD,16));//設(shè)置字體 g.setColor(color);//設(shè)置顏色 g.fillRect(0, 0, width, height);//繪制背景 g.setColor(reverse); g.drawString(randomString, 18, 20);//繪制隨機(jī)字符 for(int i=0,n=random.nextInt(100);i<n;i++){ //畫最多100個噪音點 g.drawRect(random.nextInt(width), random.nextInt(height), 1, 1); } ServletOutputStream out= response.getOutputStream();//轉(zhuǎn)成JPEG格式 JPEGImageEncoder encoder=JPEGCodec.createJPEGEncoder(out);//編碼器 encoder.encode(bi); //對圖片進(jìn)行編碼 out.flush(); //輸出到客戶端 } /** * 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,會自動生成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下新建一個html,展示驗證碼
<!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="換個圖片" onclick="reloadImage()" id="btn"> </body> </html>
啟動Tomcat,輸入網(wǎng)址:http://localhost:8080/servlet/identity.html,效果如下:
點擊‘換個圖片',會生成新的驗證碼。
以上就是本文的全部內(nèi)容,希望對大家的學(xué)習(xí)有所幫助,也希望大家多多支持腳本之家。
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