利用谷歌 kaptcha 进行验证码生成

package main.com.smart.controller;

import com.google.code.kaptcha.Producer;
import main.com.smart.utils.CaptchaProducer;
import main.com.smart.utils.RedisClient;
import org.apache.log4j.Logger;
import org.apache.log4j.spi.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;

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

import com.google.code.kaptcha.Constants;

import java.awt.image.BufferedImage;

/**
 * 验证码 生成控制器
 *
 * @author yang ming
 * @create 2016-04-29 12:17
 */


@Controller
@RequestMapping("/kaptcha")
public class CaptchaController {
    /**
     * 使用方法
     * get: http://localhost:8080/smart/kaptcha
     */
    private static final Logger log = Logger.getLogger(CaptchaController.class);
    @Autowired
    private Producer captchaProducer = null;

    @RequestMapping
    public ModelAndView getKaptchaImage(HttpServletRequest request, HttpServletResponse response) throws Exception {
        RedisClient client = RedisClient.getInstance();
        //在控制器中获取验证码
        //String kaptchaExpected = (String) request.getSession().getAttribute(com.google.code.kaptcha.Constants.KAPTCHA_SESSION_KEY);
        log.info("获取验证");

        log.info(Constants.KAPTCHA_SESSION_KEY);
        HttpSession session = request.getSession();
        String code1 = client.getValue(Constants.KAPTCHA_SESSION_KEY);
        String code = String.valueOf(session.getAttribute(Constants.KAPTCHA_SESSION_KEY));
        //System.out.println("******************验证码是: " + code + "******************");

        response.setDateHeader("Expires", 0);

        // Set standard HTTP/1.1 no-cache headers.
        response.setHeader("Cache-Control", "no-store, no-cache, must-revalidate");

        // Set IE extended HTTP/1.1 no-cache headers (use addHeader).
        response.addHeader("Cache-Control", "post-check=0, pre-check=0");

        // Set standard HTTP/1.0 no-cache header.
        response.setHeader("Pragma", "no-cache");

        // return a jpeg
        response.setContentType("image/jpeg");

        // create the text for the image
        String[] array = CaptchaProducer.getCaptchaText();
        //String capText = captchaProducer.createText();
        //int param1 = (int)capText.charAt(0);
        //int param2 = (int)capText.charAt(1);
        Integer result =  Integer.valueOf(array[0]) + Integer.valueOf(array[1]);

        // store the text in the session
        client.setValue(Constants.KAPTCHA_SESSION_KEY, result.toString());
        //session.setAttribute(Constants.KAPTCHA_SESSION_KEY, result);

        // create the image with the text
        BufferedImage bi = captchaProducer.createImage(array[0]+"+"+array[1]+"=?");
        ServletOutputStream out = response.getOutputStream();

        // write the data out
        ImageIO.write(bi, "jpg", out);
        try {
            out.flush();
        } finally {
            out.close();
        }
        return null;
    }

}