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JavaWeb登陆验证码

2016-07-25 11:49 375 查看

本测试通过简单servlet实现

页面JS：

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!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 refershCheckCode(){
var image=document.getElementById("check");
image.src="checkCodeServlet?time="+new Date().getTime();
}
<%
if(request.getParameter("code")!=null){
out.println("alert('验证码错误')");
}
%>
</script>
</head>
<body>
<div style="position:absolute; width:300px;left:50%;margin-left:-150px;top:200px;">
<form action="loginServlet">
<table width="100%" cellpadding="6">
<tr>
<td>账号</td>
<td>
<input type="text" name="userName" style="width:170px">
</td>
</tr>
<tr>
<td>密码</td>
<td>
<input type="password" name="userPwd" style="width:170px">
</td>
</tr>
<tr>
<td>验证码</td>
<td>
<input type="text" name="inputCode" style="width:80px">
<a href="javascript:refershCheckCode()"><img id="check" style="position: absolute;margin-left:10px"alt="" src="checkCodeServlet"></a>
</td>
</tr>
<tr>
<td colspan="2" align="center">
<input type="submit" value="提交">
<input type="reset" value="取消">
</td>
</tr>
</table>
</form>
</div>
</body>
</html>

验证码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.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class CheckCodeServlet extends HttpServlet {

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
int width=80,height=22;
//创建一个图片对象
BufferedImage image=new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
//得到图片画布
Graphics g=image.getGraphics();
Random r = new Random();
//通过画布对象来绘制当前图片
//填充一个矩形
g.setColor(new Color(r.nextInt(255),r.nextInt(255),r.nextInt(255)));
g.fillRect(0, 0, width, height);

//绘制干扰线
for(int i=0;i<4;i++){
g.setColor(new Color(r.nextInt(255), r.nextInt(255), r.nextInt(255)));
g.drawLine(r.nextInt(width), r.nextInt(height), r.nextInt(width), r.nextInt(height));
}

String base="abcdefghijklmnopqrstuvwxyz0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
String code="";
String code1="";
for(int i=0;i<4;i++){
int index=r.nextInt(base.length());
if(i==3){
code+=base.charAt(index)+"";
}else{
code+=base.charAt(index)+" ";
}
code1+=base.charAt(index)+"";
}

request.getSession().setAttribute("checkCode", code1);
g.setFont(new Font("宋体",Font.BOLD,20));
g.drawString(code, 2, 20);

ImageIO.write(image, "JPEG", response.getOutputStream());
}

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request, response);
}

}

参数传值

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class LoginServlet extends HttpServlet {

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String inputCode = request.getParameter("inputCode");
String checkCode = request.getSession().getAttribute("checkCode").toString();
if(inputCode.equalsIgnoreCase(checkCode)){
response.sendRedirect("index.jsp");
}else{
response.sendRedirect("login.jsp?code=0");
}
}

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}

}

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