kaptcha验证码的使用

kaptcha验证码的使用

1.首先在pom.xml文件中导入Maven依赖

			com.github.penggle
			kaptcha
			2.3.2

2.在web.xml文件中配置一个servlet

		
		Kaptcha
		com.google.code.kaptcha.servlet.KaptchaServlet
		
			
               kaptcha.border
		no
	
		
		
	    kaptcha.textproducer.font.color
		red
		
	
		
		kaptcha.image.width
		135
	
		
	
		kaptcha.textproducer.char.string
			ACDEFHKPRSTWX345679
		
		
		
			kaptcha.image.height
			50
		
		
		
			kaptcha.textproducer.font.size
			43
		
		
		
			kaptcha.noise.color
			black
		
		
		
			kaptcha.textproducer.char.length
			4
		
		
		
			kaptcha.textproducer.font.names
			Arial
		
	
	
	
		Kaptcha
		/Kaptcha
	

3.页面代码如下

	验证码
	 
		

					
		


向后端提交数据

var verifyCodeActual = $('#j_captcha').val();
		if (!verifyCodeActual) {
			$.toast('请输入验证码！');
			return;
		}
		formData.append("verifyCodeActual", verifyCodeActual);

4.js交互

function changeVerifyCode(img) {
	img.src = "../Kaptcha?" + Math.floor(Math.random() * 100);
}

5.后端验证

import javax.servlet.http.HttpServletRequest;

public class CodeUtil {
	public static boolean checkVerifyCode(HttpServletRequest request) {
		String verifyCodeExpected = (String) request.getSession().getAttribute(
				com.google.code.kaptcha.Constants.KAPTCHA_SESSION_KEY);
		String verifyCodeActual = HttpServletRequestUtil.getString(request,
				"verifyCodeActual");
		if (verifyCodeActual == null
				|| !verifyCodeActual.equalsIgnoreCase(verifyCodeExpected)) {
			return false;
		}
		return true;
	}
}



import javax.servlet.http.HttpServletRequest;

public class HttpServletRequestUtil {
	public static int getInt(HttpServletRequest request, String name) {

		try {
			return Integer.decode(request.getParameter(name));
		} catch (Exception e) {
			return -1;
		}
	}

	public static long getLong(HttpServletRequest request, String name) {

		try {
			return Long.valueOf(request.getParameter(name));
		} catch (Exception e) {
			return -1;
		}
	}

	public static Double getDouble(HttpServletRequest request, String name) {

		try {
			return Double.valueOf(request.getParameter(name));
		} catch (Exception e) {
			return -1d;
		}
	}

	public static Boolean getBoolean(HttpServletRequest request, String name) {

		try {
			return Boolean.valueOf(request.getParameter(name));
		} catch (Exception e) {
			return false;
		}
	}

	public static String getString(HttpServletRequest request, String name) {
		try {
			String result = request.getParameter(name);
			if (result != null) {
				result = result.trim();
			}
			if ("".equals(result))
				result = null;
			return result;
		} catch (Exception e) {
			return null;
		}

	}
}