圖片驗證碼防暴力破解_Java

實現一個簡單的登錄驗證碼

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實現原理

1.後臺生成驗證碼傳到頁面
2.登錄驗證輸入驗證碼是否正確

實現過程

1.引入一個生成驗證碼的工具類，網上很多 隨便找一個根據需求改一下就可以

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字體，系統裏沒有的話需要安裝字體，字體只顯示大寫，去掉了1,0,i,o幾個容易混淆的字符，以及佔用太寬的字符W
	public static final String VERIFY_CODES = "23456789ABCDEFGHJKLMNPQRSTUVXYZ";
	private static Random random = new Random();


	/**
	 * 使用系統默認字符源生成驗證碼
	 * @param verifySize    驗證碼長度
	 * @return
	 */
	public static String generateVerifyCode(int verifySize){
		return generateVerifyCode(verifySize, VERIFY_CODES);
	}
	/**
	 * 使用指定源生成驗證碼
	 * @param verifySize    驗證碼長度
	 * @param sources   驗證碼字符源
	 * @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();
	}

	/**
	 * 生成隨機驗證碼文件,並返回驗證碼值
	 * @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;
	}

	/**
	 * 輸出隨機驗證碼圖片流,並返回驗證碼值
	 * @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;
	}

	/**
	 * 生成指定驗證碼圖像文件
	 * @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;
		}
	}

	/**
	 * 輸出指定驗證碼圖片流
	 * @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);// 設置邊框色
		g2.fillRect(0, 0, w, h);

		Color c = getRandColor(200, 250);
		g2.setColor(c);// 設置背景色
		g2.fillRect(0, 2, w, h-4);

		//繪製干擾線
		Random random = new Random();
		g2.setColor(getRandColor(160, 200));// 設置線條的顏色
		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);
		}

		// 添加噪點
		float yawpRate = 0.05f;// 噪聲率
		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);// 使圖片扭曲

		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中生成驗證碼並放入session

//生成圖片驗證碼
	@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.前端登錄頁面
只有主要代碼，部分已經省略 

用戶名：<input id="name" type="text">
密碼：<input id="password" type="passwpord">
驗證碼：<input id="vercode"type="text">
<img src="${ctx}/home/verifyCode" title="看不清，點擊刷新" onclick="reloadValidCode()" id="imgcode"/>

 JS（ajax）

//驗證碼刷新
 function reloadValidCode() {
	$("#imgcode").prop('src', "${ctx}/home/verifyCode?timed=" + new Date().getMilliseconds());
	    }
//登錄提交
$.ajax({
      url: "${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)
           }
          }
        });	    

後端登錄驗證

@ResponseBody
    @PostMapping("/login")
    public JSONResponse loginValidate(
            @RequestParam(value = "realName") String realName,
            @RequestParam(value = "password") String password,
			@RequestParam(value = "verificationCode") String verificationCode){
   		    //登錄驗證（略）
   		    ...
   		    String verCode = String.valueOf(request.getSession().getAttribute("securityCode"));
	        verCode = verCode.toUpperCase();
	        //判斷圖片驗證碼
			if (verCode.equals(verificationCode)){
				HttpSession session = request.getSession();
				return JSONResponseDiretor.buildSuccessJSONResponse(null);
			}
	        return JSONResponseDiretor.buildErrorJSONResponse(ResponseEnum.LOGIN_VERIFICATIONCODE_ERROR, null);
	    }
    }