【Java】登录验证码

Html：

 <input id="verifyCode" name="verifyCode" type="text"
                         value="" onclick="JavaScript:this.value=''" /></span><cite><img id="imageCode" alt="验证码" src="<%=request.getContextPath()%>/getCodeImage.do" onclick="resetCode()"></cite>

Java：

 package cn.hk.base.action;

 import java.awt.Color;
 import java.awt.Font;
 import java.awt.Graphics;
 import java.awt.Graphics2D;
 import java.awt.image.BufferedImage;
 import java.io.IOException;
 import java.util.Random;

 import javax.imageio.ImageIO;
 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.ResponseBody;

 import cn.zy.action.BaseAction;

 @Controller
 public class CommonAction extends BaseAction{

     /**
      *
      */
     private static final long serialVersionUID = -8902195523837272079L;

      /**
      * 验证图片宽
      */
     private static final int WIDTH = 114;
     /**
      * 验证图片高度
      */
     private static final int HEIGHT = 46;

     @RequestMapping("/getCodeImage.do")
     public @ResponseBody void getCodeImage(HttpServletRequest request,HttpServletResponse response) throws IOException{
          // 获得图片
         BufferedImage image = new BufferedImage(WIDTH, HEIGHT,
                 BufferedImage.TYPE_INT_RGB);
         // 获取画笔
         Graphics g = image.getGraphics();
         // 设置边框
         g.setColor(Color.LIGHT_GRAY);
         g.fillRect(0, 0, WIDTH, HEIGHT);

         g.setColor(Color.WHITE);
         g.fillRect(1, 1, WIDTH - 2, HEIGHT - 2);
       /*  // 设置背景
         g.setColor(Color.getColor("#68B71A"));
         g.drawRect(1, 1, WIDTH-2, HEIGHT-2);*/
         // 干扰线
         g.setColor(Color.GREEN);
         int x1, y1;
         int x2, y2;
         Random r = new Random();
         for (int i = 0; i < 10; i++) {
             // 起始xy
             x1 = r.nextInt(WIDTH);
             y1 = r.nextInt(HEIGHT);
             // 结束xy
             x2 = r.nextInt(WIDTH);
             y2 = r.nextInt(HEIGHT);

             g.drawLine(x1, y1, x2, y2);
         }
         // 验证码
         g.setColor(Color.RED);
         g.setFont(new Font("宋体", Font.BOLD, 20));
         String base = "qwertyupasdfghjkzxcvbnm23456789QWERTYUIOPASDFGHJKLZXCVBNM";
         StringBuilder sb = new StringBuilder();
         char ch = '\u0000';
         int degree = 0;
         r = new Random();
         int startX = 8;
         for (int i = 0; i < 4; i++) {
             ch = base.charAt(r.nextInt(base.length()));

             // 设置旋转, ±20°
             degree = r.nextInt() % 20;
             ((Graphics2D) g).rotate(degree * Math.PI / 180, startX, 14);
             g.drawString(ch + "", startX, 26);
             // 取消旋转
             ((Graphics2D) g).rotate(-degree * Math.PI / 180, startX, 14);

             startX += 24;
             sb.append(ch);
         }
         request.getSession().setAttribute("checkCode", sb.toString().toLowerCase());
         // 发送给页面
         response.setContentType("image/jpeg");
         response.setDateHeader("expries", -1);
         response.setHeader("cache-control", "no-cache");
         response.setHeader("progma", "no-cache");
         ImageIO.write(image, "jpg", response.getOutputStream());

     }
 }