vue+SSM实现验证码功能

<el-form-item prop="code">
     <img src="checkCode" alt="" width="100" height="32" class="passcode" style="height:43px;cursor:pointer; float:left;"onclick="this.src=this.src+'?'">>
    <el-input v-model="login.code" placeholder="请输入验证码" style="width: 100px; float:center" auto-complete="off"></el-input>
</el-form-item>

@RequestMapping(value="/checkCode")
 public void checkCode(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
 //设置相应类型,告诉浏览器输出的内容为图片
   response.setContentType("image/jpeg");
   HttpSession session = request.getSession();
   //设置响应头信息，告诉浏览器不要缓存此内容
   response.setHeader("pragma", "no-cache");
   response.setHeader("Cache-Control", "no-cache");
   response.setDateHeader("Expire", );
   RandomValidateCode randomValidateCode = new RandomValidateCode();
   try {
    randomValidateCode.getRandcode(request, response);
   } catch (Exception e) {
    e.printStackTrace();
   }
 }

public class RandomValidateCode {
public static final String RANDOMCODEKEY = "randomcode_key";//放到session中的key
 private Random random = new Random();
 private String randString = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";//随机产生的字符串
 private int width = 80;//图片宽
 private int height = 26;//图片高
 private int lineSize = 40;//干扰线数量
 private int stringNum = 4;//随机产生字符数量
 /**
 * 生成随机图片
 */
 public void getRandcode(HttpServletRequest request,
   HttpServletResponse response) {
  HttpSession session = request.getSession();
  //BufferedImage类是具有缓冲区的Image类,Image类是用于描述图像信息的类
  BufferedImage image = new BufferedImage(width,height,BufferedImage.TYPE_INT_BGR);
  //产生Image对象的Graphics对象,改对象可以在图像上进行各种绘制操作
  Graphics g = image.getGraphics();
  g.fillRect(0, 0, width, height);
  g.setFont(new Font("Times New Roman",Font.ROMAN_BASELINE,18));
  g.setColor(getRandColor(160, 200));
  //绘制干扰线
  for(int i=0;i<=lineSize;i++){
   drowLine(g);
  }
  //绘制随机字符
  String randomString = "";
  for(int i=1;i<=stringNum;i++){
   randomString=drowString(g,randomString,i);
  }
  session.removeAttribute(RANDOMCODEKEY);
  session.setAttribute(RANDOMCODEKEY, randomString);
  g.dispose();
  try {
  //将内存中的图片通过流动形式输出到客户端
   ImageIO.write(image, "JPEG", response.getOutputStream());
  } catch (Exception e) {
   e.printStackTrace();
  }
 }
 /*
 * 获得字体
 */
 private Font getFont(){
  return new Font("Fixedsys",Font.CENTER_BASELINE,18);
 }
 /*
 * 获得颜色
 */
 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);
 }
 /*
 * 绘制字符串
 */
 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;
 }
 /*
 * 绘制干扰线
 */
 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);
 }
 /*
 * 获取随机的字符
 */
 public String getRandomString(int num){
  return String.valueOf(randString.charAt(num));
 }
}

submitForm(login) {
   this.$refs[login].validate((valid) => {
    if (valid) {
     this.loadings(); //加载动画
    // window.alert(this.login.code);
     this.$http.post('/login', {
      username: this.login.username,
      password: this.login.password,
      remember: this.login.remember,
      code:this.login.code
     }).then(result => {
     //window.alert(result);
      // 判断用户是否登录成功，后端返回JSON格式数据，不然娶不到数据
      if (result.body.success) {
      alert("success");
       window.location.href = "/listStudentInfo";
       this.loading.close(); //关闭动画加载
      } else {
       // 弹出错误信息框
       this.$emit(
        'submit-form',
        this.$message({
         message:result.body.message,
         type: 'warning',
         duration: 6000
        }),
       );
       // 清空表单状态
       this.$refs[login].resetFields();
      }
     });
   }
    else {
     this.$emit(
      'submit-form',
      this.$message({
       message: '输入信息有误！',
       type: 'warning',
       duration: 6000
      }),
     );
     return false;
    }
   });
  },
@RequestMapping("/login")
public Result Login( @RequestParam(value = "username", required = false) String username,
   @RequestParam(value = "password", required = false) String password,
   @RequestParam(value = "remember", required = false) String remember,
   @RequestParam(value = "code", required = false) String code,
   HttpServletRequest request
   ) {
String error = null;
HttpSession session = request.getSession();
 System.out.println(code);
 //System.out.println(session.getAttribute( RandomValidateCode.RANDOMCODEKEY));
if(username==null||session.getAttribute( RandomValidateCode.RANDOMCODEKEY).equals(code)) {
//System.out.println("code 有问题");
return new Result(false, error);
}
//System.out.println(password);
//System.out.println("调试");
Subject subject=SecurityUtils.getSubject();
UsernamePasswordToken token=new UsernamePasswordToken(username,password);
if (remember != null) {
   if (remember.equals("true")) {
    //说明选择了记住我
    token.setRememberMe(true);
   } else {
    token.setRememberMe(false);
   }
  } else {
   token.setRememberMe(false);
  }
System.out.println(token.isRememberMe());
try {
subject.login(token);
Result re=new Result(true, "success");
return new Result(true,error);
} catch (UnknownAccountException e) {
  System.out.println( "登陆出错");
  error = "用户账户不存在，错误信息：" + e.getMessage();
 }catch (IncorrectCredentialsException ex) {
 System.out.println( "用户名和密码不匹配");
 error = "用户名或密码错误，错误信息：" + ex.getMessage();
 }catch (AuthenticationException e) {
 System.out.println( "其他的登陆错误");
 error = "错误信息：" + e.getMessage();
 }
return new Result(false, error);
}

session.setAttribute("key","value");
session.getAttribute("key");