public class RandomValidateCodeUtil {


 public static final String RANDOMCODEKEY= "RANDOMVALIDATECODEKEY";//放到session中的key
 private String randString = "0123456789";//隨機(jī)產(chǎn)生只有數(shù)字的字符串 private String
 //private String randString = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";//隨機(jī)產(chǎn)生只有字母的字符串
 //private String randString = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";//隨機(jī)產(chǎn)生數(shù)字與字母組合的字符串
 private int width = 95;// 圖片寬
 private int height = 25;// 圖片高
 private int lineSize = 40;// 干擾線數(shù)量
 private int stringNum = 4;// 隨機(jī)產(chǎn)生字符數(shù)量

 private static final Logger logger = LoggerFactory.getLogger(RandomValidateCodeUtil.class);

 private Random random = new Random();

 /**
  * 獲得字體
  */
 private Font getFont() {
  return new Font("Fixedsys", Font.CENTER_BASELINE, 18);
 }

 /**
  * 獲得顏色
  */
 private Color getRandColor(int fc, int bc) {
  if (fc > 255)
   fc = 255;
  if (bc > 255)
   bc = 255;
  int r = fc + random.nextInt(bc - fc - 16);
  int g = fc + random.nextInt(bc - fc - 14);
  int b = fc + random.nextInt(bc - fc - 18);
  return new Color(r, g, b);
 }

 /**
  * 生成隨機(jī)圖片
  */
 public void getRandcode(HttpServletRequest request, HttpServletResponse response) {
  HttpSession session = request.getSession();
  // BufferedImage類是具有緩沖區(qū)的Image類,Image類是用于描述圖像信息的類
  BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);
  Graphics g = image.getGraphics();// 產(chǎn)生Image對(duì)象的Graphics對(duì)象,改對(duì)象可以在圖像上進(jìn)行各種繪制操作
  g.fillRect(0, 0, width, height);//圖片大小
  g.setFont(new Font("Times New Roman", Font.ROMAN_BASELINE, 18));//字體大小
  g.setColor(getRandColor(110, 133));//字體顏色
  // 繪制干擾線
  for (int i = 0; i <= lineSize; i++) {
   drowLine(g);
  }
  // 繪制隨機(jī)字符
  String randomString = "";
  for (int i = 1; i <= stringNum; i++) {
   randomString = drowString(g, randomString, i);
  }
  logger.info(randomString);
  //將生成的隨機(jī)字符串保存到session中
  session.removeAttribute(RANDOMCODEKEY);
  session.setAttribute(RANDOMCODEKEY, randomString);
  g.dispose();
  try {
   // 將內(nèi)存中的圖片通過流動(dòng)形式輸出到客戶端
   ImageIO.write(image, "JPEG", response.getOutputStream());
  } catch (Exception e) {
   logger.error("將內(nèi)存中的圖片通過流動(dòng)形式輸出到客戶端失敗>>>> ", e);
  }

 }

 /**
  * 繪制字符串
  */
 private String drowString(Graphics g, String randomString, int i) {
  g.setFont(getFont());
  g.setColor(new Color(random.nextInt(101), random.nextInt(111), random
    .nextInt(121)));
  String rand = String.valueOf(getRandomString(random.nextInt(randString
    .length())));
  randomString += rand;
  g.translate(random.nextInt(3), random.nextInt(3));
  g.drawString(rand, 13 * i, 16);
  return randomString;
 }

 /**
  * 繪制干擾線
  */
 private void drowLine(Graphics g) {
  int x = random.nextInt(width);
  int y = random.nextInt(height);
  int xl = random.nextInt(13);
  int yl = random.nextInt(15);
  g.drawLine(x, y, x + xl, y + yl);
 }

 /**
  * 獲取隨機(jī)的字符
  */
 public String getRandomString(int num) {
  return String.valueOf(randString.charAt(num));
 }
}

/**
 * 生成驗(yàn)證碼
 */
@RequestMapping(value = "/getVerify")
public void getVerify(HttpServletRequest request, HttpServletResponse response) {
 try {
  response.setContentType("image/jpeg");//設(shè)置相應(yīng)類型,告訴瀏覽器輸出的內(nèi)容為圖片
  response.setHeader("Pragma", "No-cache");//設(shè)置響應(yīng)頭信息，告訴瀏覽器不要緩存此內(nèi)容
  response.setHeader("Cache-Control", "no-cache");
  response.setDateHeader("Expire", 0);
  RandomValidateCodeUtil randomValidateCode = new RandomValidateCodeUtil();
  randomValidateCode.getRandcode(request, response);//輸出驗(yàn)證碼圖片方法
 } catch (Exception e) {
  logger.error("獲取驗(yàn)證碼失敗>>>> ", e);
 }
}

<div class="row">
 <div class="col-xs-6 pull_left">
  <div class="form-group">
   <input class="form-control" type="tel" id="verify_input" placeholder="請(qǐng)輸入驗(yàn)證碼" maxlength="4">
  </div>
 </div>
 <div class="col-xs-6 pull_left">
  <a href="javascript:void(0);" rel="external nofollow" title="點(diǎn)擊更換驗(yàn)證碼">
   <img id="imgVerify" src="" alt="更換驗(yàn)證碼" height="36" width="100%" onclick="getVerify(this);">
  </a>
 </div>
</div>

//獲取驗(yàn)證碼
function getVerify(obj){
 obj.src = httpurl + "/sys/getVerify?"+Math.random();
}

/**
 * 忘記密碼頁面校驗(yàn)驗(yàn)證碼
 */
@RequestMapping(value = "/checkVerify", method = RequestMethod.POST, headers = "Accept=application/json")
public boolean checkVerify(@RequestBody Map<String, Object> requestMap, HttpSession session) {
 try{
  //從session中獲取隨機(jī)數(shù)
  String inputStr = requestMap.get("inputStr").toString();
  String random = (String) session.getAttribute("RANDOMVALIDATECODEKEY");
  if (random == null) {
   return false;
  }
  if (random.equals(inputStr)) {
   return true;
  } else {
   return false;
  }
 }catch (Exception e){
  logger.error("驗(yàn)證碼校驗(yàn)失敗", e);
  return false;
 }
}