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(guò)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(guò)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));
  }
}

<!--html/bady代碼-->

<div >
  <div >
    <div >
      <input type="tel" id="verify_input" placeholder="請(qǐng)輸入驗(yàn)證碼" maxlength="4">
    </div>
  </div>
  <div >
    <a href="javascript:void(0);" rel="external nofollow" title="點(diǎn)擊更換驗(yàn)證碼">
      <img id="imgVerify" src="login/getVerify" alt="更換驗(yàn)證碼" height="36" width="170" onclick="getVerify(this);">
    </a>
  </div>
  <input type="button" onclick="aVerify()" value="提交">
</div>
</body>

<!--js中的代碼-->
<script type="text/javascript" src="./js/jquery.min.js"></script>
<script>

  //獲取驗(yàn)證碼
  /*function getVerify(obj){
    obj.src = "login/getVerify?"+Math.random();//原生js方式
  }*/
  
  //獲取驗(yàn)證碼
  function getVerify() {
    // $("#imgCode").on("click", function() {
    $("#imgVerify").attr("src", 'login/getVerify?' + Math.random());//jquery方式
    // });
  }

  function aVerify(){
    var value =$("#verify_input").val();
    // alert(value);
    $.ajax({
      async: false,
      type: 'post',
      url: 'login/checkVerify',
      dataType: "json",
      data: {
        verifyInput: value
      },
      success: function (result) {
        if (result) {
          alert("success!");
        } else {
          alert("failed!");
        }
        // window.location.reload();
        getVerify();
      }
    });
  }
</script>

@RestController
@RequestMapping("/login")
public class Picverifyaction {
  private final static Logger logger = LoggerFactory.getLogger(Picverifyaction.class);

  /**
   * 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);
    }
  }

  /**
   * 校驗(yàn)驗(yàn)證碼
   */
  @RequestMapping(value = "/checkVerify", method = RequestMethod.POST,headers = "Accept=application/json")
  public boolean checkVerify(@RequestParam String verifyInput, HttpSession session) {
    try{
      //從session中獲取隨機(jī)數(shù)
      String inputStr = verifyInput;
      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;
    }
  }
}