标签:描述 user awt valueof 缓冲 页面 点击图片 ali sla
下面是一张项目结构图,实现功能前需要先搭建好SpringMVC框架。
RandomValidateCode.java——是生成验证码的类
Constants.java——定义了一个常量,用于保存验证码字段
ToolController——生成验证码和校验验证码的处理器映射器
这3个类的源码如下(有带注释):
RandomValidateCode.java
package com.zwk.common; import java.awt.Color; import java.awt.Font; import java.awt.Graphics; import java.awt.image.BufferedImage; import java.util.Random; import javax.imageio.ImageIO; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; import org.springframework.stereotype.Component; import com.zwk.constant.Constants; @Component public class RandomValidateCode { /** * 生成代码 * * @return */ public static String createValidateCode(int size) { String seed = "1234567890qwertyuiopasdfghjklzxcvbnmQWERTYUIOPASDFGHJKLZXCVBNM"; int len = seed.length(); char[] p = new char[size]; for (int i = 0; i < size; i++) { p[i] = seed.charAt((int) Math.floor(Math.random() * len)); } return new String(p); } private final Random random = new Random(); private final String randString = "123456789ABCDEFGHIJKLMNPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";// 随机产生的字符串 private final int width = 135;// 图片宽 private final int height = 40;// 图片高 private final int lineSize = 50;// 干扰线数量 private final int stringNum = 4;// 随机产生字符数量 private final int fontSize = 30;// 随机产生字符数量 /** * 生成随机图片 */ public void getRandcode(HttpServletRequest request, HttpServletResponse response) { HttpSession session = request.getSession(); // BufferedImage类是具有缓冲区的Image类,Image类是用于描述图像信息的类 BufferedImage image = new BufferedImage(this.width, this.height, BufferedImage.TYPE_INT_BGR); Graphics g = image.getGraphics();// 产生Image对象的Graphics对象,改对象可以在图像上进行各种绘制操作 g.fillRect(0, 0, this.width, this.height); g.setFont(new Font("Times New Roman", Font.ROMAN_BASELINE, this.fontSize)); g.setColor(this.getRandColor(110, 133)); // 绘制干扰线 for (int i = 0; i <= this.lineSize; i++) { this.drawLine(g); } // 绘制随机字符 String randomString = ""; for (int i = 1; i <= this.stringNum; i++) { randomString = this.drawString(g, randomString, i); }
// 将获取得到的randomString存入定义在Constants类的常量,用于接下来校验时获取 session.removeAttribute(Constants.RANDOM_CODE_KEY); session.setAttribute(Constants.RANDOM_CODE_KEY, randomString); // System.out.println(randomString); g.dispose(); try { // 禁止图像缓存。 response.setHeader("Pragma", "no-cache"); response.setHeader("Cache-Control", "no-cache"); response.setDateHeader("Expires", 0); // 将内存中的图片通过流动形式输出到客户端 ImageIO.write(image, "JPEG", response.getOutputStream()); } catch (Exception e) { e.printStackTrace(); } } /** * 获取随机的字符 */ public String getRandomString(int num) { return String.valueOf(this.randString.charAt(num)); } /** * 绘制干扰线 */ private void drawLine(Graphics g) { int x = this.random.nextInt(this.width); int y = this.random.nextInt(this.height); int xl = this.random.nextInt(13); int yl = this.random.nextInt(15); g.drawLine(x, y, x + xl, y + yl); } /** * 绘制字符串 */ private String drawString(Graphics g, String randomString, int i) { g.setFont(this.getFont()); g.setColor(new Color(this.random.nextInt(155), this.random.nextInt(123), this.random.nextInt(176))); String rand = String.valueOf(this.getRandomString(this.random.nextInt(this.randString.length()))); randomString += rand; g.translate(this.random.nextInt(3), this.random.nextInt(3)); g.drawString(rand, (this.width / this.stringNum - 14) * i, this.height - 7); return randomString; } /** * 获得字体 */ private Font getFont() { return new Font("Times New Roman", Font.CENTER_BASELINE, this.fontSize); } /** * 获得颜色 */ private Color getRandColor(int fc, int bc) { if (fc > 255) { fc = 255; } if (bc > 255) { bc = 255; } int r = fc + this.random.nextInt(bc - fc - 16); int g = fc + this.random.nextInt(bc - fc - 14); int b = fc + this.random.nextInt(bc - fc - 18); return new Color(r, g, b); } }
Constants.java
package com.zwk.constant; public class Constants { public static final String RANDOM_CODE_KEY = "RANDOM_CODE_KEY";
}
ToolController.java
package com.zwk.controller; import javax.annotation.Resource; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestParam; import com.zwk.common.RandomValidateCode; import com.zwk.constant.Constants; @Controller public class ToolController { @Resource RandomValidateCode code; @RequestMapping("/vcode") public void vcode(HttpServletRequest request,HttpServletResponse response) { code.getRandcode(request, response); System.out.println("进入获取随机生成的验证码"); } @RequestMapping("doLogin") public String doLogin(HttpServletRequest request,HttpServletResponse response,@RequestParam String vcode) { //获取session中的code String sessionCode=(String)request.getSession().getAttribute(Constants.RANDOM_CODE_KEY); System.out.println("随机生成:"+sessionCode); System.out.println("用户输入:"+vcode); //将随机生成的验证码和用户输入的验证码统一转化成大写或者小写 vcode=vcode.toLowerCase(); sessionCode=sessionCode.toLowerCase(); if(vcode.equals(sessionCode)) { request.setAttribute("error", "验证码输入正确"); return "i18n"; }else { request.setAttribute("error", "验证码输入错误"); return "login"; } } }
以上的代码加注释可以读懂。接下来就可以在我们的login页面生成一张带验证码图片:
贴出<body></body>内的代码如下:
<body> <script type="text/javascript"> function changecode(){ document.getElementById(‘vcode‘).src="vcode.html?c="+Math.random(); } </script> <div style="margin: 0 auto;margin-top: 100px; "> <form action="doLogin.html" method="post"> 用户名:<input type="text" name="user"><br/> 验证码: <input type="text" name="vcode"> <img id="vcode" alt="换一张" src="vcode.html" onclick="changecode()"/> <input type="submit"> </form> <br/><span style="color:red">${error }</span> </div> </body>
<img id="vcode" alt="换一张" src="vcode.html" onclick="changecode()"/>
用img生成一张图片, id定义与js中的changecode()获取的id一致。
不要使用<input type="image" src="vcode.html" onclick="cjhangecode()"/>,否则一点击时会刷新页面,而不是局部刷新图片。
在js中的方法中: document.getElementById(‘vcode‘).src="vcode.html?c="+Math.random(); 要传递一个变量,这样每次请求时才会去调用刷新验证码。
src="vcode.html" 是因为我在使用springmvc配置时拦截的是以.html结尾的
这部分属于springmvc的基本知识,用的时候可以直接复制源码,少量改动即可实现。
以下是我的运行结果:
点击图片换一张时,只局部刷新图片,而不会刷新整个页面!
标签:描述 user awt valueof 缓冲 页面 点击图片 ali sla
原文地址:https://www.cnblogs.com/zwk2018/p/9585019.html