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Javaweb实现验证码

前端

添加样式

编写代码

   
              
    
  				
     
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           用户名 
           
 
             
           
 
          
 
          
 
           密码 
           
 
             
           
 
          
 
          
 
           验证码 
           
 
             
           
 
           
 
             
           
 
          
 
          
 
            
          
 
         
 
        
        
       
      
      
    
     
  
    
   

配置web.xml文件

       
    
     com.FM.servlet
        
    
     com.FM.servlet.ValidationCodeServlet
        
    
     ValidationCodeServlet
        
    
     com.FM.servlet.ValidationCodeServlet
     
   

       
    
     ValidationCodeServlet
        
    
     /ValidationCodeServlet
      
   

后台

package com.FM.servlet;import java.io.IOException;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.imageio.ImageIO;import javax.servlet.http.HttpSession;import java.awt.*;import java.awt.image.BufferedImage;import java.io.OutputStream;import java.util.Random;public class ValidationCodeServlet extends HttpServlet {
   	private static final long serialVersionUID = 1L;               public ValidationCodeServlet() {
           super();            }		protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
   				  //获得验证码集合的长度        int charsLength = codeChars.length();        //下面3条记录是关闭客户端浏览器的缓冲区        //这3条语句都可以关闭浏览器的缓冲区，但是由于浏览器的版本不同，对这3条语句的支持也不同        //因此，为了保险起见，同时使用这3条语句来关闭浏览器的缓冲区        resp.setHeader("ragma", "No-cache");        resp.setHeader("Cache-Control", "no-cache");        resp.setDateHeader("Expires", 0);        //设置图形验证码的长和宽        int width = 90, height = 30;        BufferedImage image = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);        Graphics g = image.getGraphics(); //获得用于输出文字的Graphics对象        Random random = new Random();        g.setColor(getRandomColor(180, 250));        g.fillRect(0, 0, width, height);        g.setFont(new Font("Times New Roman",Font.ITALIC,height));        g.setColor(getRandomColor(120, 180));        //用户保存最后随机生成的验证码        StringBuilder validationCode = new StringBuilder();        //验证码的随机字体        String[] fontNames = {
   "Times New Roman","Book antiqua","Arial"};        //随机生成4个验证码        for(int i = 0; i < 4; i++){
               //随机设置当前验证码的字符的字体            g.setFont(new Font(fontNames[random.nextInt(3)],Font.ITALIC,height));            //随机获得当前验证码的字符            char codeChar = codeChars.charAt(random.nextInt(charsLength));            validationCode.append(codeChar);            //随机设置当前验证码字符的颜色            g.setColor(getRandomColor(10, 100));            //在图形上输出验证码字符，x和y都是随机生成的            g.drawString(String.valueOf(codeChar), 16*i + random.nextInt(7), height-random.nextInt(6));        }        //获得HttpSession对象        HttpSession session = req.getSession();        //设置session对象5分钟失效        session.setMaxInactiveInterval(5*60);        //将验证码保存在session对象中,key为validation_code        session.setAttribute("validation_code", validationCode.toString());        //关闭Graphics对象        g.dispose();        OutputStream outS = resp.getOutputStream();        ImageIO.write(image, "JPEG", outS);    }		protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
   				doGet(request, response);	}	//图形验证码的字符集，系统将随机从这个字符串中选择一些字符作为验证码    private static String codeChars = "123456789abcdefghijklmnpqrstuvwxyzABCDEFGHIJKLMNPQRSTUVWXYZ";    //返回一个随机颜色    private static Color getRandomColor(int minColor, int maxColor){
           Random random = new Random();        if(minColor > 255){
               minColor = 255;        }        if(maxColor > 255){
               maxColor = 255;        }        //获得r的随机颜色值        int red = minColor + random.nextInt(maxColor-minColor);        //g        int green = minColor + random.nextInt(maxColor-minColor);        //b        int blue = minColor + random.nextInt(maxColor-minColor);        return new Color(red,green,blue);    }}

效果图：

Springboot添加验证码

项目结构

依赖

           
               
    
     com.github.penggle
                
    
     kaptcha
                
    
     2.3.2
            
   

控制类

CommonController

package com.habse.car_position.Controller;import com.google.code.kaptcha.impl.DefaultKaptcha;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Component;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.GetMapping;import javax.imageio.ImageIO;import javax.servlet.ServletOutputStream;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import java.awt.image.BufferedImage;import java.io.ByteArrayOutputStream;/*验证码 */@Controllerpublic class CommonController {
       @Autowired    private DefaultKaptcha captchaProducer;    @GetMapping("/common/kaptcha")    public void defaultKaptcha(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) throws Exception {
           byte[] captchaOutputStream = null;        ByteArrayOutputStream imgOutputStream = new ByteArrayOutputStream();        try {
               //生产验证码字符串并保存到session中            String verifyCode = captchaProducer.createText();            httpServletRequest.getSession().setAttribute("verifyCode", verifyCode);            BufferedImage challenge = captchaProducer.createImage(verifyCode);            ImageIO.write(challenge, "jpg", imgOutputStream);        } catch (IllegalArgumentException e) {
               httpServletResponse.sendError(HttpServletResponse.SC_NOT_FOUND);            return;        }        captchaOutputStream = imgOutputStream.toByteArray();        httpServletResponse.setHeader("Cache-Control", "no-store");        httpServletResponse.setHeader("Pragma", "no-cache");        httpServletResponse.setDateHeader("Expires", 0);        httpServletResponse.setContentType("image/jpeg");        ServletOutputStream responseOutputStream = httpServletResponse.getOutputStream();        responseOutputStream.write(captchaOutputStream);        responseOutputStream.flush();        responseOutputStream.close();    }}

KaptchaConfig

package com.habse.car_position.config;import com.google.code.kaptcha.impl.DefaultKaptcha;import com.google.code.kaptcha.util.Config;import org.springframework.context.annotation.Bean;import org.springframework.stereotype.Component;import java.util.Properties;@Componentpublic class KaptchaConfig {
       @Bean    public DefaultKaptcha getDefaultKaptcha(){
           DefaultKaptcha defaultKaptcha = new DefaultKaptcha();        Properties properties = new Properties();        properties.put("kaptcha.border", "no");        properties.put("kaptcha.textproducer.font.color", "blue");        properties.put("kaptcha.image.width", "140");        properties.put("kaptcha.image.height", "40");        properties.put("kaptcha.textproducer.font.size", "30");        properties.put("kaptcha.session.key", "verifyCode");        properties.put("kaptcha.textproducer.char.space", "5");        Config config = new Config(properties);        defaultKaptcha.setConfig(config);        return defaultKaptcha;    }}

前端页面

效果图

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