Java基于springMVC的验证码案例

 ```
 Java验证码案例（基于springMVC方式）

 验证码工具类
 package com.ekyb.common.util;

 import java.awt.Color;
 import java.awt.Font;
 import java.awt.Graphics;

 import java.awt.image.BufferedImage;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 import java.util.Random;

 import javax.servlet.http.HttpServletRequest;

 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.stereotype.Component;

 /**
  * 图片验证码生成类
  *
  * @author gx
  */
 @Component("imageCode")
 public class ImageCode {
     /*
      * Spring 3支持@value注解的方式获取properties文件中的配置值，大简化了读取配置文件的代码。
      * 在applicationContext.xml文件中配置properties文件,在bean中使用@value注解获取配置文件的值
      * 即使给变量赋了初值也会以配置文件的值为准。
      */
     @Value("${ImageCode.width}")
     private int width;

     @Value("${ImageCode.height}")
     private int height;

     @Value("${ImageCode.codeLength}")
     private int codeLength;

     @Value("${ImageCode.randomString}")
     private String randomString;

     @Value("${ImageCode.sessionKey}")
     private String sessionKey;

     @Value("${ImageCode.font.name}")
     private String fontName;

     @Value("${ImageCode.font.style}")
     private int fontStyle;

     @Value("${ImageCode.font.size}")
     private int fontSize;

     public BufferedImage getImage(HttpServletRequest request) {
         // 在内存中创建图片
         BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
         // 获取图片上下文
         Graphics g = image.getGraphics();
         // 生成随机类
         Random random = new Random();
         // 设定背景颜色
         g.setColor(getRandColor(100, 250));
         g.fillRect(0, 0, width, height);
         // 设定字体
         g.setFont(new Font(fontName, fontStyle, fontSize));
         g.setColor(getRandColor(160, 200));
         for (int i = 0; i < 155; i++) {
             int x = random.nextInt(width);
             int y = random.nextInt(height);
             int xl = random.nextInt(12);
             int yl = random.nextInt(12);
             g.drawLine(x, y, xl, y + yl);
         }
         // 取随机产生的认证码
         String sRand = randomRand(codeLength);
         int strWidth = width / 2 - g.getFontMetrics().stringWidth(sRand) / codeLength - fontSize;
         int strHeight = height / 2 + g.getFontMetrics().getHeight() / 4;
         for (int i = 0; i < codeLength; i++) {
             String rand = sRand.substring(i, i + 1);
             g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));
             g.drawString(rand, 13 * i + 6 + strWidth, strHeight);
         }
         //System.out.println(sRand);
         request.getSession().setAttribute(sessionKey, sRand);
         request.setAttribute("sRand", sRand);
         g.dispose();
         return image;
     }

     public static String randomResult(int length) {
         String[] i = { "1", "2", "3", "4", "5", "6", "7", "8", "9", "0" };
         List<String> l = new ArrayList<String>();
         l.addAll(Arrays.asList(i));
         Random ran = new Random();
         String s = "";
         while (l.size() > 10 - length)
             s += l.remove(ran.nextInt(l.size()));
         s = s.replaceAll("^(0)(\\d)", "$2$1");
         return s;
     }

     // 给定范围获取随机颜色
     public Color getRandColor(int fc, int bc) {
         Random random = new Random();
         if(fc > 255) {
             fc = 255;
         }
         if(bc > 255) {
             bc = 255;
         }
         int r = fc + random.nextInt(bc - fc);
         int g = fc + random.nextInt(bc - fc);
         int b = fc + random.nextInt(bc - fc);
         return new Color(r, g, b);

     }

     private String randomRand(int n) {
         String rand = "";
         int len = randomString.length() - 1;
         double r;
         for (int i = 0; i < n; i++) {
             r = ((Math.random())) * len;
             rand = rand + randomString.charAt((int) r);
         }
         return rand;
     }

     public int getWidth() {
         return width;
     }

     public void setWidth(int width) {
         this.width = width;
     }

     public int getHeight() {
         return height;
     }

     public void setHeight(int height) {
         this.height = height;
     }

     public int getCodeLength() {
         return codeLength;
     }

     public void setCodeLength(int codeLength) {
         this.codeLength = codeLength;
     }

     public String getRandomString() {
         return randomString;
     }

     public void setRandomString(String randomString) {
         this.randomString = randomString;
     }

     public String getSessionKey() {
         return sessionKey;
     }

     public void setSessionKey(String sessionKey) {
         this.sessionKey = sessionKey;
     }

     public String getFontName() {
         return fontName;
     }

     public void setFontName(String fontName) {
         this.fontName = fontName;
     }

     public int getFontStyle() {
         return fontStyle;
     }

     public void setFontStyle(int fontStyle) {
         this.fontStyle = fontStyle;
     }

     public int getFontSize() {
         return fontSize;
     }

     public void setFontSize(int fontSize) {
         this.fontSize = fontSize;
     }

 }

 -----------------------------------------------
 读取config.properties配置的验证码和图片设置

 #ImageCode生成器配置
 ImageCode.width=120
 ImageCode.height=38
 ImageCode.codeLength=4
 ImageCode.randomString=ABCDEFGHIJKLMNPQRSTUVWXYZ1234567890abcdefghijkmnpqrstuvwxyz
 ImageCode.sessionKey=SESSIONCODE
 ImageCode.font.name=Times New Roman
 ImageCode.font.style=0
 ImageCode.font.size=18
 -------------------------------------------------
 springMVC action中的代码
 package com.ekyb.common.auContract.action;

 import java.io.IOException;

 import javax.annotation.Resource;
 import javax.imageio.ImageIO;
 import javax.servlet.ServletOutputStream;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;

 import org.springframework.stereotype.Controller;
 import org.springframework.web.bind.annotation.RequestMapping;

 import com.ekyb.common.util.ImageCode;

 @Controller
 @RequestMapping(value="/yanZhen")
 public class YanZhenMaAction {
     /*
      * @Resource默认按 byName 自动注入,是J2EE提供的， 需导入Package: javax.annotation.Resource;
      *
      * @Resource有两个中重要的属性：name和type ，而Spring将@Resource注解的name属性解析为bean的
      * 名字，而type属性则解析为bean的类型。所以如果使用name属性，则使用byName的自动注入策略，而使用 type属性时则使用
      * byType自动注入策略。如果既不指定name也不指定type属性，这时将通过反射机制使用by Name自动注入策略。
      */
     @Resource
     ImageCode imageCode;

     private static String sRand;

     @RequestMapping(value = "/openLoginPage")
     public String openLoginPage(HttpServletRequest request, HttpServletResponse response) {
         String msg=request.getParameter("msg");
         if(msg==null&& msg.isEmpty()){
             //得到用户读入框信息，如果没有输入或者为空，直接跳转到验证失败页面
             return "error";
         }else{
             if(sRand.equalsIgnoreCase((msg))){
                 //得到用户输入的验证码匹配成功，跳转到验证通过页面
                 return "ok";
             }else{
                 //得到用户输入的验证码匹配失败，跳转到验证失败页面
                 return "error";
             }
         }
     }

     @RequestMapping(value = "/getImage")
     public void getImage(HttpServletRequest request, HttpServletResponse response
             ) throws IOException {
         // 禁止图片缓存
         response.setHeader("Pragma", "no-cache");
         response.setHeader("Cache-Control", "no-cache");
         response.setDateHeader("Expires", 0);
         response.setContentType("image/jpeg");
         // 将图像输出到servlet输出流中
         ServletOutputStream sos = response.getOutputStream();
         ImageIO.write(imageCode.getImage(request), "jpeg", sos);
         sos.close();
         sRand=(String)request.getAttribute("sRand");
         String result="ok";

     }
 }
 -------------------------------------------------
 前端登录页面代码
 <%@ page language="java" pageEncoding="utf-8"%>
 <%
     String path = request.getContextPath();
     String basePath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort() + path + "/";
 %>
 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
 <html>
 <head>
 <base href="<%=basePath%>">
 <title>登录</title>
 </head>
 <script type="text/javascript" src="js/jquery-easyui/jquery.min.js"></script>
 <body>
     <!-- cursor: pointer;鼠标放上显示手;   title:鼠标放上时显示的文字 -->
     <img id="imageCode" alt="" src="" onclick="checkcode()" style="cursor: pointer;" title="点我更换验证码" />
     <br>
     <form action="<%=basePath%>yanZhen/openLoginPage" method="post">
         <input type="text" value="" name="msg">
         <input type="submit" value="提交">
     </form>
 </body>
 <script type="text/javascript">
     var basePath = "<%=basePath%>";
     $(function() {
         checkcode();
     });
     function checkcode() {
         var XMLHttp = null;
         if (window.XMLHttpRequest) {
             XMLHttp = new XMLHttpRequest();
         } else if (window.ActiveXObject) {
             XMLHttp = new ActiveXObject("Microsoft.XMLHTTP");
         }
         XMLHttp.onreadystatechange = function() {
             if (XMLHttp.readyState == 4) {
                 //改变验证码图片
                 $("#imageCode").attr("src",(basePath + "/yanZhen/getImage?" + new Date()));
             }
         };
         //将请求发送出去
         //加上 new Date()防止浏览器缓存，不重新发送请求
         XMLHttp.open("GET", basePath + "/yanZhen/getImage?" + new Date(), true);
         XMLHttp.send(null);
     }
 </script>
 </html>
 -----------------------------------------------------
 登录成页面ok.jsp
 <%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
 <%
     String path = request.getContextPath();
     String basePath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort()
             + path + "/";
 %>

 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
 <html>
 <head>
 <base href="<%=basePath%>">

 <title>验证通过</title>
 </head>
 <body>
     <h2>验证通过</h2>
 </body>
 </html>
 -------------------------------------------------
 登录失败页面error.jsp
 <%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
 <%
     String path = request.getContextPath();
     String basePath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort()
             + path + "/";
 %>
 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
 <html>
 <head>
 <base href="<%=basePath%>">

 <title>验证失败</title>
 </head>

 <body>
     <h2>验证失败</h2>
 </body>
 </html>
 --------------------
 ==****注意个别路径根据自己的文件路劲更改==
如果有误请多指教
 ```