生成验证码
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2022-05-19 15:57:14
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生成验证码
使用javaweb
生成验证码。
目录结构
CheckCodeServlet.java
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@WebServlet("/CheckCodeServlet")
public class CheckCodeServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String resultTip="images/error.png";
//获取用户输入的验证码
String checkcodeClient = request.getParameter("checkcode");
//真实的验证码值
String checkcodeServer = (String)request.getSession().getAttribute("CKECKCODE");
if(checkcodeServer.equals(checkcodeClient)) {
resultTip="images/right.png";
}
response.setContentType("text/html; charset=UTF-8");
PrintWriter writer = response.getWriter();//输出流
writer.write(resultTip);
writer.flush();
writer.close();
}
}
img.jsp
<%@page import="java.awt.*"%>
<%@page import="javax.imageio.ImageIO"%>
<%@page import="java.awt.Color"%>
<%@page import="java.awt.Graphics"%>
<%@page import="java.awt.image.BufferedImage"%>
<%@page import="java.util.Random"%>
<%@ page language="java" contentType="image/jpeg; charset=UTF-8"
pageEncoding="UTF-8"%>
<%!
//随机产生颜色值
public Color getColor(){
Random ran =new Random();
int r=ran.nextInt(256);
int g=ran.nextInt(256);
int b=ran.nextInt(256);
return new Color(r,g,b);
}
//产生随机数字
public String getNum(){
//1000-9999
int ran=(int) (Math.random()*9000)+1000;
return String.valueOf(ran);
}
%>
<%
//禁止缓存,防止验证码过期
response.setHeader("pragma", "no-cache");
response.setHeader("cache-control", "no-cache");
response.setHeader("Expires", "0");
//绘制验证码
BufferedImage image=new BufferedImage(80,30,BufferedImage.TYPE_INT_RGB);
//画笔
Graphics graphics=image.getGraphics();
graphics.fillRect(0, 0, 80, 30);
//绘制干扰线条
for(int i=0;i<60;i++){
Random ran=new Random();
int xBegin=ran.nextInt(80);//产生小于80的随机整数
int yBegin=ran.nextInt(30);
int xEnd=ran.nextInt(xBegin+10);
int yEnd=ran.nextInt(yBegin+10);
graphics.setColor(getColor()) ;
//绘制线条
graphics.drawLine(xBegin, yBegin, xEnd, yEnd);
}
graphics.setFont(new Font("seif",Font.BOLD,20));
//绘制验证码
graphics.setColor(Color.BLACK);
String checkCode=getNum();
StringBuffer sb=new StringBuffer();
for(int i=0;i<checkCode.length();i++){
sb.append(checkCode.charAt(i)+" ");//验证码的每一位数字
}
//绘制验证码
graphics.drawString(sb.toString(), 15, 20);
//将验证码真实值保存在session中,供使用时比较真实性
session.setAttribute("CKECKCODE", checkCode);
//真实的产生图片
ImageIO.write(image,"jpeg",response.getOutputStream());
//关闭
out.clear();
out=pageContext.pushBody();
%>
index.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<style type="text/css">
#checkcodeId{
height:20px;
width:100px;
}
</style>
<script type="text/javascript" src="js/jquery.min.js"></script>
<script type="text/javascript" >
$(document).ready(function(){
$("#checkcodeId").blur(function(){
var $checkcode =$("#checkcodeId").val();
if($checkcode==""){
alert("请输入验证码!")
}else{
//校验,输入的值发送到服务端
//服务端将获取的值和真实值对比
$.post(
"CheckCodeServlet",//服务端地址
"checkcode="+$checkcode,//验证码的值
function(result){
//alert(data);
var resultHtml= $("<img src='"+result+"' height='25px' width='25px' id='isRight' />");
$("#tip").html(resultHtml);
}
);
}
})
});
function reloadCheckImg(){
$("#imgEWM").attr("src","img.jsp?t="+(new Date().getTime()));
$("#isRight").css("visibility","hidden");
$("#checkcodeId").val("");
}
</script>
<title>验证码</title>
</head>
<body>
<a href="javascript:reloadCheckImg()">
<img src="img.jsp" id="imgEWM"/>点我刷新
</a>
</br></br>
验证码:
<input type="text" name="checkcode" id="checkcodeId" maxlength="4" placeholder="请输入验证码" />
<!-- 获得验证码图片 -->
<span id="tip"></span>
</body>
</html>