不使用session，借助redis实现验证码

　　 @RequestMapping(value="loginCode")
    @ResponseBody
    public String getCode(){
        PrintWriter out = null;
        JSONObject jsono = new JSONObject();
        try {

//验证码工具类
            ValidateCode vCode = new ValidateCode(55,25,4,80);
            String randomCode = vCode.randomCode();
            String encCode = DesUtil.strEnc(randomCode+System.currentTimeMillis(), "1", "2", "3");
            //存储验证码字符串,过期时间为1分钟
            redisTemplate.opsForValue().set(encCode, randomCode);
            redisTemplate.expire(encCode, 1, TimeUnit.MINUTES);
            //存储验证码生成器,过期时间为1分钟
            redisTemplate.opsForValue().set(encCode+"ValidateCode", SerializeUtil.serialize(vCode));
            redisTemplate.expire(encCode+"ValidateCode", 1, TimeUnit.MINUTES);
            jsono.put("success", true);
            jsono.put("message", encCode);
        } catch (Exception e) {
            e.printStackTrace();
            jsono.put("success", true);
            jsono.put("message", "inner error.");
        } finally{
            if(out != null) {
                out.flush();
                out.close();
            }
        }
        return jsono.toString();
    }

　　@RequestMapping(value="loginCodeImage")
    public void getCodeImage(String codeAuth, HttpServletResponse response){
        if(codeAuth == null) return;
        String randomCode = (String) redisTemplate.opsForValue().get(codeAuth);
        if(randomCode == null) return;
        ValidateCode vCode = (ValidateCode)SerializeUtil.unserialize((byte[])redisTemplate.opsForValue().get(codeAuth+"ValidateCode"));
        //产生图片
        vCode.createCode(randomCode);
        if(vCode == null) return;
        // 设置响应的类型格式为图片格式  
        response.setContentType("image/jpeg");  
        //禁止图像缓存。  
        response.setHeader("Pragma", "no-cache");  
        response.setHeader("Cache-Control", "no-cache");  
        response.setDateHeader("Expires", 0);  
        try {
            vCode.write(response.getOutputStream());
        } catch (IOException e) {
            e.printStackTrace();
        }  
    }

　　public static ImageIcon getCodeImage(){
        String data = JavaRequest.sendPost("loginCode", null);
        JSONObject result = JSONObject.fromObject(data);
        if((Boolean) result.get("success")){
             JavaRequest.codeAuth = result.getString("message");
             ImageIcon codeImg = null;
             try{
                  codeImg = new ImageIcon(new URL(“.....”));
             } catch (Exception e) {
                 e.printStackTrace();
                 return null;
             }
             return codeImg;
        } else {
            System.out.println("获取验证码图片: " + result);
            return null;
        }
    }

　　ImageIcon codeImg = JavaRequest.getCodeImage();
   if(codeImg == null){
        codeImg = new ImageIcon("获取失败的图片.png");
   }

/////////////////

JLable codeImgLabel = new JLabel(codeImg);