JSP页面验证码实现
程序员文章站
2022-06-24 08:02:09
首先在JSP页面加上生成图片的链接 运行后，jsp页面会发出"auth/code"请求生成验证码，并将验证码放置于session中用于验证，运行效果如下 我们在jsp页面上加上输入验证码的输入框及提交按钮，点击按钮后进行验证码判断 后台会比将收入的验证码与放置于session中的验证码进行比对，并输 ......
首先在jsp页面加上生成图片的链接
<img type="image" src="auth/authcode" id="codeimage" name="codeimage" style="cursor:pointer;"/>，src需要我们自己实现，实现逻辑如下
运行后，jsp页面会发出"auth/code"请求生成验证码，并将验证码放置于session中用于验证，运行效果如下
我们在jsp页面上加上输入验证码的输入框及提交按钮，点击按钮后进行验证码判断
后台会比将收入的验证码与放置于session中的验证码进行比对，并输出结果给jsp页面进行相应处理，当判断为失败，则刷新验证码
最后，相对完整的页面和逻辑都已实现，代码如下
jsp页面代码
<%@ page contenttype="text/html;charset=utf-8" language="java" iselignored="false" %>
<%@ page import="java.util.*" %>
<html>
<head>
<title>title</title>
</head>
<%--<script src="js/jquery.min.js"></script>--%>
<script src="https://libs.baidu.com/jquery/1.8.3/jquery.js"></script>
<script type="text/javascript">
function submitform() {
var inputcode=$("#authcode").attr("value");
var list={"inputcode":inputcode};
$.ajax({
//请求方式
type : "post",
//请求的媒体类型
contenttype: "application/x-www-form-urlencoded",
//请求地址
url : "auth/checkcode",
//数据，json字符串
data :list,
datatype:"json",
//请求成功
success : function(result) {
alert(result);
if(result=="1"){
alert("验证通过");
}else{
alert("验证失败，重新刷新验证码");
flushauthcode();
}
},
//请求失败，包含具体的错误信息
error : function(e){
alert(e.responsetext);
}
});
}
function flushauthcode() {
//重新刷新验证码
$("#codeimage").attr("src","auth/authcode?abc="+math.random());
}
</script>
<body>
<form id="authform" action="checkcode">
<input type="text" id="authcode" name="authcode">
<img type="image" src="auth/authcode" id="codeimage" name="codeimage" style="cursor:pointer;"/>
<button type="button" id="submitbtn" name="submitbtn" value="提交" onclick="submitform()"/>
</form>
</body>
</html>
后台代码
package com.founderit.controller;
import org.springframework.stereotype.controller;
import org.springframework.web.bind.annotation.*;
import javax.imageio.imageio;
import javax.servlet.http.httpservletrequest;
import javax.servlet.http.httpservletresponse;
import javax.servlet.http.httpsession;
import java.awt.*;
import java.awt.image.bufferedimage;
import java.io.ioexception;
import java.util.random;
@controller
@requestmapping("auth")
public class auth {
private char[] codesequence = { 'a', '1','b', 'c', '2','d','3', 'e','4', 'f', '5','g','6', 'h', '7','i', '8','j',
'k', '9' ,'l', '1','m', '2','n', 'p', '3', 'q', '4', 'r', 's', 't', 'u', 'v', 'w',
'x', 'y', 'z'};
@requestmapping("authcode")
public void getcode(httpservletresponse response, httpsession session) throws ioexception {
int width = 63;
int height = 37;
random random = new random();
//设置response头信息
//禁止缓存
response.setheader("pragma", "no-cache");
response.setheader("cache-control", "no-cache");
response.setdateheader("expires", 0);
//生成缓冲区image类
bufferedimage image = new bufferedimage(width, height, 1);
//产生image类的graphics用于绘制操作
graphics g = image.getgraphics();
//graphics类的样式
g.setcolor(this.getcolor(200, 250));
g.setfont(new font("times new roman",0,28));
g.fillrect(0, 0, width, height);
//绘制干扰线
for(int i=0;i<40;i++){
g.setcolor(this.getcolor(130, 200));
int x = random.nextint(width);
int y = random.nextint(height);
int x1 = random.nextint(12);
int y1 = random.nextint(12);
g.drawline(x, y, x + x1, y + y1);
}
//绘制字符
string strcode = "";
for(int i=0;i<4;i++){
string rand = string.valueof(codesequence[random.nextint(codesequence.length)]);
strcode = strcode + rand;
g.setcolor(new color(20+random.nextint(110),20+random.nextint(110),20+random.nextint(110)));
g.drawstring(rand, 13*i+6, 28);
}
//将字符保存到session中用于前端的验证
session.setattribute("authcode", strcode.tolowercase());
g.dispose();
imageio.write(image, "jpeg", response.getoutputstream());
response.getoutputstream().flush();
}
public color getcolor(int fc,int bc){
random random = new random();
if(fc>255)
fc = 255;
if(bc>255)
bc = 255;
int r = fc + random.nextint(bc - fc);
int g = fc + random.nextint(bc - fc);
int b = fc + random.nextint(bc - fc);
return new color(r,g,b);
}
@requestmapping(value = "checkcode",method = requestmethod.post)
@responsebody
public string checkauthcode(@requestparam(value = "inputcode") string inputcode, httpservletrequest request){
string checkcode=(string) request.getsession().getattribute("authcode");
//返回1 代表判断通过,0代表失败
string iscode=checkcode.equals(inputcode)?"1":"0";
return iscode;
}
}