【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());
       
    }
}