基于Java的图片点选汉字验证码的实现，以及Js配置

前端运行效果图：

• 安全方面：
  
  • 后端取随机背景图，随机汉字，随机位置，随机色值生成一张图传给前端
  • 后端将随机生成的汉字传给前端
  • 前端根据用户点击获取鼠标坐标，生成字符串，传给后端进行校验

• 代码片
  
  • Jsp （随后附上H5代码片）

<!--  图片点选汉字验证码  --><section id="captcha_sec" class="input-container" style="display: none;" ><spring:message code="screen.welcome.label.captcha.accesskey"var="captchaAccessKey" /><input type="hidden" id="captchaHidenInputPart" name="captcha" value="" /><div style="width: 400px; height: 132px"><img class="verify_img" id="testMouseImg"alt="<spring:message code="captcha.required" />"onclick="this.src='captcha.jpg?'+Math.random()" src="captcha.jpg"style="float: right; width: 400px; height: 132px; margin-top: 0px; left: 0; position: relative; border-radius: 4px;" /></div><div cssClass="required login_input_2 loginInput captcha " cssErrorClass="error"id="captcha" size="25" tabindex="2" path="captcha" class="select_by_order"accesskey="${captchaAccessKey}" htmlEscape="true" autocomplete="off"></div><div class="select_by_order required login_input_2 loginInput captcha" accesskey="screen.welcome.label.captcha.accesskey" style="border: 1px solid #DADADA;border-radius: 4px; display: block;" id="captcha">请依次点击  <span id="forMousePos"></span></div><div class="select_by_order required login_input_2 loginInput captcha" style="border: 1px solid #DADADA; border-radius: 4px; display: none; background: #FFEEE1" id="selectFaildiv"><i class="iconfont icon-cuowu-xiankuang" style="color: #FF0000">    校验失败，请重新校验</i></div><div class="select_by_order required login_input_2 loginInput captcha" style="border: 1px solid #DADADA; border-radius: 4px; display: none; background: rgba(152,251,152,0.3)" id="selectSuccessdiv"><i class="iconfont icon-zhengque" style="color: #3CB371">    校验通过</i></div></section>

• js
  前端获取坐标用了offset()函数。
  之前用的client()。二者的区别是，offset()获取的是当前元素的坐标，从而不需考虑滚动的位移值。

<script type="text/javascript">$(document).ready(function () {var tenantId = $("#tenantId").val();var clientX, clientY, clientXY;var client = '';var attach_url = "";$.ajax({url: '',type: 'get',data: "tenant=" + tenantId,success: function (data, status) {}, fail: function (err, status) {setDefaultImgsAndTitle();}});/* 返回汉字  */$.ajax({url: '',type: 'get',success: function(subData){//根据后端要求选择不同的拼接方式subData="  “" + subData.data.substr(0, 1) + "” “" + subData.data.substr(2, 1) + "” “" + subData.data.substr(4, 1) + "” “" + subData.data.substr(6, 1) + "”";$("#forMousePos").text(subData);}, fail: function(err,status){console.log()}});/* jquery 获取鼠标坐标函数 */function mousePos(e) {var x, y;var e = e || window.event;return {x: e.offsetX,y: e.offsetY};};var n = 0;$('#testMouseImg').on('click',function(e){offsetX = mousePos(e).x;offsetY = mousePos(e).y;offsetXY = offsetX + "-" + offsetY;coordinateToString(offsetXY); n++;$('#testMouseImg').html(n);if(n == 4){client = client.substring(0,client.length-1);/* 点击四次后传回坐标 */$.ajax({url: '' + zzzz,type: 'get',success: function(data){if(data.status === "true"){$("#captcha").val(client);$("#captcha").attr("value",client);$("#captchaHidenInputPart").attr("value",client);console.log('校验成功  ',data.status);$("#captcha").text("验证通过   " );$("#selectSuccessdiv").css('display','block');$("#captcha").css('display','none');$("#selectFaildiv").css('display','none');} else {                console.log('校验失败 ',data.status); $("#captcha").css('display','none');$("#selectFaildiv").css('display','block');$("#selectSuccessdiv").css('display','none');client = '';n = 0;$.ajax({url: '',type: 'get',success: function(){$('#testMouseImg').attr('src', '/cas/xxx.jpg');}});$.ajax({url: '',type: 'get',success: function(subData){console.log(subData);//根据后端要求选择不同的拼接方式subData="  “" + subData.data.substr(0, 1) + "” “" + subData.data.substr(2, 1) + "” “" + subData.data.substr(4, 1) + "” “" + subData.data.substr(6, 1) + "”";$("#forMousePos").text(subData.data);}, });//设置定时器setTimeout(function(){selectFaild()}, 1000);}},/* fail */});console.log(client);}})function coordinateToString(xy){client = client + xy + "@";}function setTimer(){setTimeout(selectFaild(), 1000);}function selectFaild(){$("#captcha").css('display','block');$("#selectFaildiv").css('display','none');}
</script>     

JAVA

• 日志中打印出坐标，分别为：x, y, width, height
  
• 算法机制为：
  
  *
  *

Java部分
Github: https://github.com/YuyaoYan/captcha