图片验证码防暴力破解_Java

小鱼儿 2023-02-09 13:25 1阅读 0赞

# 实现一个简单的登录验证码 #

--------------------

# 实现原理 #

1.后台生成验证码传到页面  
2.登录验证输入验证码是否正确

# 实现过程 #

1.引入一个生成验证码的工具类，网上很多 随便找一个根据需求改一下就可以

package com.utils;
    
    /**
     * ${DESCRIPTION}
     *
     * @author 
     * @create 
     **/
    import java.awt.Color;
    import java.awt.Font;
    import java.awt.Graphics;
    import java.awt.Graphics2D;
    import java.awt.RenderingHints;
    import java.awt.image.BufferedImage;
    import java.io.File;
    import java.io.FileOutputStream;
    import java.io.IOException;
    import java.io.OutputStream;
    import java.util.Arrays;
    import java.util.Random;
    
    import javax.imageio.ImageIO;
    
    public class VerifyCodeUtils{
    
    	//使用到Algerian字体，系统里没有的话需要安装字体，字体只显示大写，去掉了1,0,i,o几个容易混淆的字符，以及占用太宽的字符W
    	public static final String VERIFY_CODES = "23456789ABCDEFGHJKLMNPQRSTUVXYZ";
    	private static Random random = new Random();
    
    
    	/**
    	 * 使用系统默认字符源生成验证码
    	 * @param verifySize    验证码长度
    	 * @return
    	 */
    	public static String generateVerifyCode(int verifySize){
    		return generateVerifyCode(verifySize, VERIFY_CODES);
    	}
    	/**
    	 * 使用指定源生成验证码
    	 * @param verifySize    验证码长度
    	 * @param sources   验证码字符源
    	 * @return
    	 */
    	public static String generateVerifyCode(int verifySize, String sources){
    		if(sources == null || sources.length() == 0){
    			sources = VERIFY_CODES;
    		}
    		int codesLen = sources.length();
    		Random rand = new Random(System.currentTimeMillis());
    		StringBuilder verifyCode = new StringBuilder(verifySize);
    		for(int i = 0; i < verifySize; i++){
    			verifyCode.append(sources.charAt(rand.nextInt(codesLen-1)));
    		}
    		return verifyCode.toString();
    	}
    
    	/**
    	 * 生成随机验证码文件,并返回验证码值
    	 * @param w
    	 * @param h
    	 * @param outputFile
    	 * @param verifySize
    	 * @return
    	 * @throws IOException
    	 */
    	public static String outputVerifyImage(int w, int h, File outputFile, int verifySize) throws IOException{
    		String verifyCode = generateVerifyCode(verifySize);
    		outputImage(w, h, outputFile, verifyCode);
    		return verifyCode;
    	}
    
    	/**
    	 * 输出随机验证码图片流,并返回验证码值
    	 * @param w
    	 * @param h
    	 * @param os
    	 * @param verifySize
    	 * @return
    	 * @throws IOException
    	 */
    	public static String outputVerifyImage(int w, int h, OutputStream os, int verifySize) throws IOException{
    		String verifyCode = generateVerifyCode(verifySize);
    		outputImage(w, h, os, verifyCode);
    		return verifyCode;
    	}
    
    	/**
    	 * 生成指定验证码图像文件
    	 * @param w
    	 * @param h
    	 * @param outputFile
    	 * @param code
    	 * @throws IOException
    	 */
    	public static void outputImage(int w, int h, File outputFile, String code) throws IOException{
    		if(outputFile == null){
    			return;
    		}
    		File dir = outputFile.getParentFile();
    		if(!dir.exists()){
    			dir.mkdirs();
    		}
    		try{
    			outputFile.createNewFile();
    			FileOutputStream fos = new FileOutputStream(outputFile);
    			outputImage(w, h, fos, code);
    			fos.close();
    		} catch(IOException e){
    			throw e;
    		}
    	}
    
    	/**
    	 * 输出指定验证码图片流
    	 * @param w
    	 * @param h
    	 * @param os
    	 * @param code
    	 * @throws IOException
    	 */
    	public static void outputImage(int w, int h, OutputStream os, String code) throws IOException{
    		int verifySize = code.length();
    		BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
    		Random rand = new Random();
    		Graphics2D g2 = image.createGraphics();
    		g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,RenderingHints.VALUE_ANTIALIAS_ON);
    		Color[] colors = new Color[5];
    		Color[] colorSpaces = new Color[] { Color.WHITE, Color.CYAN,
    				Color.GRAY, Color.LIGHT_GRAY, Color.MAGENTA, Color.ORANGE,
    				Color.PINK, Color.YELLOW };
    		float[] fractions = new float[colors.length];
    		for(int i = 0; i < colors.length; i++){
    			colors[i] = colorSpaces[rand.nextInt(colorSpaces.length)];
    			fractions[i] = rand.nextFloat();
    		}
    		Arrays.sort(fractions);
    
    		g2.setColor(Color.GRAY);// 设置边框色
    		g2.fillRect(0, 0, w, h);
    
    		Color c = getRandColor(200, 250);
    		g2.setColor(c);// 设置背景色
    		g2.fillRect(0, 2, w, h-4);
    
    		//绘制干扰线
    		Random random = new Random();
    		g2.setColor(getRandColor(160, 200));// 设置线条的颜色
    		for (int i = 0; i < 20; i++) {
    			int x = random.nextInt(w - 1);
    			int y = random.nextInt(h - 1);
    			int xl = random.nextInt(6) + 1;
    			int yl = random.nextInt(12) + 1;
    			g2.drawLine(x, y, x + xl + 40, y + yl + 20);
    		}
    
    		// 添加噪点
    		float yawpRate = 0.05f;// 噪声率
    		int area = (int) (yawpRate * w * h);
    		for (int i = 0; i < area; i++) {
    			int x = random.nextInt(w);
    			int y = random.nextInt(h);
    			int rgb = getRandomIntColor();
    			image.setRGB(x, y, rgb);
    		}
    
    		shear(g2, w, h, c);// 使图片扭曲
    
    		g2.setColor(getRandColor(100, 160));
    		int fontSize = h-4;
    		Font font = new Font("Algerian", Font.PLAIN, fontSize);
    		g2.setFont(font);
    		char[] chars = code.toCharArray();
    		for(int i = 0; i < verifySize; i++){
    			//AffineTransform affine = new AffineTransform();
    			//affine.setToRotation(Math.PI / 4 * rand.nextDouble() * (rand.nextBoolean() ? 1 : -1), (w / verifySize) * i + fontSize/2, h/2);
    			//g2.setTransform(affine);
    			g2.drawChars(chars, i, 1, ((w-10) / verifySize) * i + 5, h/2 + fontSize/2 - 10);
    		}
    
    		g2.dispose();
    		ImageIO.write(image, "jpg", os);
    	}
    
    	private static Color getRandColor(int fc, int bc) {
    		if (fc > 255)
    			fc = 255;
    		if (bc > 255)
    			bc = 255;
    		int r = fc + random.nextInt(bc - fc);
    		int g = fc + random.nextInt(bc - fc);
    		int b = fc + random.nextInt(bc - fc);
    		return new Color(r, g, b);
    	}
    
    	private static int getRandomIntColor() {
    		int[] rgb = getRandomRgb();
    		int color = 0;
    		for (int c : rgb) {
    			color = color << 8;
    			color = color | c;
    		}
    		return color;
    	}
    
    	private static int[] getRandomRgb() {
    		int[] rgb = new int[3];
    		for (int i = 0; i < 3; i++) {
    			rgb[i] = random.nextInt(255);
    		}
    		return rgb;
    	}
    
    	private static void shear(Graphics g, int w1, int h1, Color color) {
    		shearX(g, w1, h1, color);
    		shearY(g, w1, h1, color);
    	}
    
    	private static void shearX(Graphics g, int w1, int h1, Color color) {
    
    		int period = random.nextInt(2);
    
    		boolean borderGap = true;
    		int frames = 1;
    		int phase = random.nextInt(2);
    
    		for (int i = 0; i < h1; i++) {
    			double d = (double) (period >> 1)
    					* Math.sin((double) i / (double) period
    					+ (6.2831853071795862D * (double) phase)
    					/ (double) frames);
    			g.copyArea(0, i, w1, 1, (int) d, 0);
    			if (borderGap) {
    				g.setColor(color);
    				g.drawLine((int) d, i, 0, i);
    				g.drawLine((int) d + w1, i, w1, i);
    			}
    		}
    
    	}
    
    	private static void shearY(Graphics g, int w1, int h1, Color color) {
    
    		int period = random.nextInt(40) + 10; // 50;
    
    		boolean borderGap = true;
    		int frames = 20;
    		int phase = 7;
    		for (int i = 0; i < w1; i++) {
    			double d = (double) (period >> 1)
    					* Math.sin((double) i / (double) period
    					+ (6.2831853071795862D * (double) phase)
    					/ (double) frames);
    			g.copyArea(i, 0, 1, h1, 0, (int) d);
    			if (borderGap) {
    				g.setColor(color);
    				g.drawLine(i, (int) d, i, 0);
    				g.drawLine(i, (int) d + h1, i, h1);
    			}
    
    		}
    
    	}
    }

2.controller中生成验证码并放入session

//生成图片验证码
    	@GetMapping(value="verifyCode")
    	public void verifyCode(Model model,HttpServletRequest request,HttpServletResponse response) {
    		try {
    			OutputStream outputStream=response.getOutputStream();
    			int w = 200, h = 80;
    			String code = VerifyCodeUtils.generateVerifyCode(4);
    			request.getSession().setAttribute("securityCode", code);
    			VerifyCodeUtils.outputImage(w, h, outputStream, code);
    			outputStream.close();
    		} catch (IOException e) {
    			e.printStackTrace();
    		}
    	}

3.前端登录页面  
只有主要代码，部分已经省略

用户名：<input id="name" type="text">
    密码：<input id="password" type="passwpord">
    验证码：<input id="vercode"type="text">
    <img src="${ctx}/home/verifyCode" title="看不清，点击刷新" onclick="reloadValidCode()" id="imgcode"/>

JS（ajax）

//验证码刷新
     function reloadValidCode() {
    	$("#imgcode").prop('src', "${ctx}/home/verifyCode?timed=" + new Date().getMilliseconds());
    	    }
    //登录提交
    $.ajax({
          url: "${ctx}/login",
          data: {'name': name,'password': password,'verificationCode':verificationCode},
          dataType: 'JSON',
          async: false,
          type: 'POST',
          success: function (data) {
             if (data.code == 200) {
              } else {
              errorAlert(data.msg)
               }
              }
            });

后端登录验证

@ResponseBody
        @PostMapping("/login")
        public JSONResponse loginValidate(
                @RequestParam(value = "realName") String realName,
                @RequestParam(value = "password") String password,
    			@RequestParam(value = "verificationCode") String verificationCode){
       		    //登录验证（略）
       		    ...
       		    String verCode = String.valueOf(request.getSession().getAttribute("securityCode"));
    	        verCode = verCode.toUpperCase();
    	        //判断图片验证码
    			if (verCode.equals(verificationCode)){
    				HttpSession session = request.getSession();
    				return JSONResponseDiretor.buildSuccessJSONResponse(null);
    			}
    	        return JSONResponseDiretor.buildErrorJSONResponse(ResponseEnum.LOGIN_VERIFICATIONCODE_ERROR, null);
    	    }
        }