验证码-Spring

package com.youself.controller;

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

import javax.imageio.ImageIO;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

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

import cn.ucfgroup.oauth.service.utils.RandomUtil;

/**
 * @ClassName: CaptchaController
 * @Description: 图片验证码服务
 * @author: admin
 * @date: 2013年12月24日 下午5:26:37
 */
@Controller
@RequestMapping("/captcha")
public class CaptchaController extends BaseController {
    
    private int width = 146;
    private int height = 48;
    private int codeLength = 4;
    private int codeX = (width - 4) / (codeLength + 1);
    private int codeY = height - 7;
    
    /**
     * @param request 上下文request
     * @param response 上下文response
     */
    @RequestMapping(value = "/get", method = RequestMethod.GET)
    public void getCaptcha(HttpServletRequest request, HttpServletResponse response) {
        String randomCode = RandomUtil.randomFixedLengthChars(codeLength); //生成随机验证码的帮助类
        char codes[] = randomCode.toCharArray();
        
        // 定义图像buffer
        BufferedImage buffImg = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        Graphics2D gd = buffImg.createGraphics();
        // 将图像填充为白色
        gd.setColor(Color.WHITE);
        gd.fillRect(0, 0, width, height);
        // 建立字体，字体的大小应该根据图片的高度来定。
        Font font = new Font("Fixedsys", Font.PLAIN, height - 10);
        // 设置字体
        gd.setFont(font);
        // 画边框。
        gd.setColor(new Color(221, 221, 221));
        gd.drawRect(0, 0, width - 1, height - 1);
        for (int i = 0; i < codeLength; i++) {
            gd.setColor(Color.BLUE);
            gd.drawString(String.valueOf(codes[i]), (i + 1) * codeX, codeY); 
            
        }
        // 将四位数字的验证码保存到Session中。 
        HttpSession session = request.getSession();
        session.setAttribute("captchaCode", randomCode);
        // 禁止图像缓存。
        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;
        try {
            sos = response.getOutputStream();
            ImageIO.write(buffImg, "jpeg", sos);
            sos.close();   
        } catch (IOException e) {
            e.printStackTrace();
        }
        
    }
}