Java Web前后端验证码验证

思路：将存入session通过jsp页面中的el表达式获取，放入js进行验证。

 // 注册验证
			function issubmit() {
				var yz = ${r_check_code};
				var inputyz = document.getElementById("r_yz").value;
				console.log(yz);
				console.log(inputyz);
				console.log(yz==inputyz);
				//是否同意服务条款
				if (selecta.checked) {
					//验证码输入是否正确
					if (yz==inputyz) {
						判断表单填写是否完整
						if (zcpassword.value!="" && zcpassword.value==zcpassword2.value && validate_idcard(zcid.value) && validate_username(zcname.value) && validate_password(zcpassword.value) && validate_password(zcpassword2.value)) {
							return true;
						} else{
							document.getElementById("span1").innerHTML = "小贴士:表单不合法请修改！";
							return false;
						}
					}else{
						document.getElementById("span1").innerHTML = "小贴士：验证码错误！";
						container.classList.add('right-panel-active');
						return false;
					}
				}else{
					alert('请确认是否同意服务条款，若不同意，则无法注册！');
					container.classList.add('right-panel-active');
					return false;
				}
			}

思路：获取页面输入，在servlet中将session获取，进行验证。

//验证码验证
		String r_yz = "'"+request.getParameter("r_yz")+"'";
		String saveCode = (String) request.getSession().getAttribute("r_check_code");//随机产生的验证码
		//如果验证码正确则往下执行
		System.out.println(r_yz.equals(saveCode));
		if (r_yz.equals(saveCode)) {
		String uid = request.getParameter("idcard");
		String uname = request.getParameter("username");
		String upassword = request.getParameter("password");
		request.setAttribute("idcard", uid);
		request.setAttribute("username", uname);
		request.setAttribute("password", upassword);
		User user = new User(uid, uname, upassword);
		int row = new UserDaoImpl().insert(user);
		request.getRequestDispatcher("RegisterAfter.jsp").forward(request, response);
		} else {
			//携带验证码错误信息进行反馈请求转发到登录页面
			request.setAttribute("rmsg", "验证码错误！");
		}