java web驗證碼完成代碼分享。本站提示廣大學習愛好者：（java web驗證碼完成代碼分享）文章只能為提供參考，不一定能成為您想要的結果。以下是java web驗證碼完成代碼分享正文
驗證碼的感化：平日的登錄或許注冊體系時，都邑請求用戶輸出驗證碼，以此差別用戶行動和盤算機法式行動，目標是有人避免歹意注冊、暴力破解暗碼等。
完成驗證碼的思緒：用 server 完成隨機生成數字和字母構成圖片的功效，用 jsp 頁面完成顯示驗證碼和用戶輸出驗證碼的功效，再用 server 類分離獲得圖片和用戶輸出的數據，斷定兩個數據能否分歧。
代碼完成
1.編寫數字、英文隨機生成的 server 類，源碼：
package com;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.PrintWriter;
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 logcheck extends HttpServlet {
public logcheck() {
super();
}
public void destroy() {
super.destroy();
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request, response);
}
/*完成的焦點代碼*/
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("image/jpeg");
HttpSession session=request.getSession();
int width=60;
int height=20;
//設置閱讀器不要緩存此圖片
response.setHeader("Pragma", "No-cache");
response.setHeader("Cache-Control", "no-cache");
response.setDateHeader("Expires", 0);
//創立內存圖象並取得圖形高低文
BufferedImage image=new BufferedImage(width, height,BufferedImage.TYPE_INT_RGB);
Graphics g=image.getGraphics();
/*
* 發生隨機驗證碼
* 界說驗證碼的字符表
*/
String chars="0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
char[] rands=new char[4];
for(int i=0;i<4;i++){
int rand=(int) (Math.random() *36);
rands[i]=chars.charAt(rand);
}
/*
* 發生圖象
* 畫配景
*/
g.setColor(new Color(0xDCDCDC));
g.fillRect(0, 0, width, height);
/*
* 隨機發生120個攪擾點
*/
for(int i=0;i<120;i++){
int x=(int)(Math.random()*width);
int y=(int)(Math.random()*height);
int red=(int)(Math.random()*255);
int green=(int)(Math.random()*255);
int blue=(int)(Math.random()*255);
g.setColor(new Color(red,green,blue));
g.drawOval(x, y, 1, 0);
}
g.setColor(Color.BLACK);
g.setFont(new Font(null, Font.ITALIC|Font.BOLD,18));
//在分歧高度輸入驗證碼的分歧字符
g.drawString(""+rands[0], 1, 17);
g.drawString(""+rands[1], 16, 15);
g.drawString(""+rands[2], 31, 18);
g.drawString(""+rands[3], 46, 16);
g.dispose();
//將圖象傳到客戶端
ServletOutputStream sos=response.getOutputStream();
ByteArrayOutputStream baos=new ByteArrayOutputStream();
ImageIO.write(image, "JPEG", baos);
byte[] buffer=baos.toByteArray();
response.setContentLength(buffer.length);
sos.write(buffer);
baos.close();
sos.close();
session.setAttribute("checkcode", new String(rands));
}
public void init() throws ServletException {
// Put your code here
}
}
2.用於顯示驗證碼的頁面：
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%> <% String path = request.getContextPath(); String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; %> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <base href="<%=basePath%>"> <title>index</title> <meta http-equiv="pragma" content="no-cache"> <meta http-equiv="cache-control" content="no-cache"> <meta http-equiv="expires" content="0"> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> <meta http-equiv="description" content="This is my page"> <!-- <link rel="stylesheet" type="text/css" href="styles.css"> --> </head> <body> <form action="yanzheng" method="post"> <input type="text" name="name" size="5" maxlength="4"> <a href="index.jsp"><img border="0" src="logcheck"></a><br><br> <input type="submit" value="提交"> </form> </body> </html>
3.用於磨練輸出的驗證碼能否准確：
package com;
import java.io.IOException;
import java.io.PrintWriter;
import javax.jms.Session;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
public class yanzheng extends HttpServlet {
public yanzheng() {
super();
}
public void destroy() {
super.destroy();
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request, response);
}
/*焦點代碼*/
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String info=null;
/*獲得輸出的值*/
String value1=request.getParameter("name");
/*獲得圖片的值*/
HttpSession session=request.getSession();
String value2=(String)session.getAttribute("checkcode");
/*比較兩個值（字母不辨別年夜小寫）*/
if(value2.equalsIgnoreCase(value1)){
info="驗證碼輸出准確";
}else{
info="驗證碼輸出毛病";
}
System.out.println(info);
request.setAttribute("info", info);
request.getRequestDispatcher("/login.jsp").forward(request, response);
}
public void init() throws ServletException {
// Put your code here
}
}
4.顯示輸出構造界面（輸出驗證碼能否准確）：
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'login.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<%=request.getAttribute("info") %>
</body>
</html>
5.項目構造、後果截圖：
以上就是本文的全體內容，願望對年夜家的進修有所贊助，也願望年夜家多多支撐。
