JavaWeb学习笔记——验证码工具的使用

女爷i 2022-06-05 02:48 183阅读 0赞

> 在用户进行注册或登录的时候通常会输入验证码，一个小例子实现验证码的使用。

#### 看一下运行结果 ####

![result][]

#### 项目目录 ####

![validatecode][]

#### 具体实现 ####

##### 1.导入所需的验证码工具jar包到lib下 #####

##### 2.Validatee.java中 #####

package com.zrxjuly.validate;
    
    import java.io.IOException;
    
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    import cn.dsna.util.images.ValidateCode;
    
    public class Validatee extends HttpServlet { 
    
        public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            // ValidateCode v = new ValidateCode(width, height, codeCount, lineCount)
            //参数：width:验证码图片的宽；height：验证码图片的高；codeCount：验证码内容的个数；lineCount：干扰线的个数
            ValidateCode validateCode = new ValidateCode(110, 30, 4, 9);
            validateCode.write(response.getOutputStream());
        }
    
        public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request, response);
        }
    }

##### 3.index.jsp中 #####

<body>
        <img src="/validate/validatee" onclick="changeImg()" /><a href="javascript:changeImg()">看不清，换一张</a>
      </body>
      <script type="text/javascript"> function changeImg() { // 获取img节点 var img = document.getElementsByTagName("img")[0]; // 加time参数：若不加，点击的时候验证码不会改变，因为浏览器会有缓存 img.src = "/validate/validatee?time=" + new Date().getTime(); }

##### 4.部署运行项目就可以看到效果啦 #####

[result]: /images/20220605/db0912e0f6de4369bcd0d7106373fc29.png
[validatecode]: /images/20220605/19f3594c168b4d39ab419cc0087b725c.png