JavaWeb验证码：以登陆为例

2018-08-21 浏览次数:

一、说明

这里是在前面的jqueryAjax：以用户登陆为基础上进行增添的，验证码是通过网上查资料，借鉴大神的代码，稍作改进而完成的。
在utils添加Verification.java,在web包中添加VerServlet.java,修改Login.jsp，修改Login.java

二、实现

1.login.jsp

<%@ page language="java" contentType="text/html; charset=utf-8"
    pageEncoding="utf-8" import="java.util.*" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<c:set var="ctx" value="${pageContext.request.contextPath}" />
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>登陆</title>
<script type="text/javascript">
var contextPath="${ctx}";
</script>
<script type="text/javascript" src="${ctx}/common/jquery-1.11.1.min_044d0927.js"></script>
<script type="text/javascript" src="${ctx}/js/login.js"></script>
 <script type="text/javascript">
function changeImg(){
    var img = document.getElementById("img"); 
    //var img=$("#img").val();
    img.src = "${ctx}/VerSerlvet?id="+Math.random();
} 
</script> 
</head>
<body>
<form>

登录名：
<input type="text" name="name" id="name" value=""/><br/>
密码：
<input type="password" name="password" id="password" value=""/><br/>
验证码：
<input type="text" name="verificate" id="verificate" value=""/> 
<img id="img" src="${ctx}/VerSerlvet" />
  <a href='#' onclick="javascript:changeImg();">看不清？</a>
<br/>
<input type="button" value="登陆" onclick="login();" >
</form>
</body>
</html>

2.Verification.java

package pers.zx.util;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.geom.AffineTransform;
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 Verification {
	//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
    public static final String VERIFY_CODES = "23456789ABCDEFGHJKLMNPQRSTUVWXYZ";
    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)));//在sources长度的任意位置插入字符然后拼接到verifyCode后
        }
        return verifyCode.toString();
    }
     
    /**
     * 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;
    }
     
     
    /**
     * 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.ITALIC, 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);
            }
 
        }
 
    }
}

3.VerServlet.java

package pers.zx.web;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import pers.zx.util.Verification;

/**
 * Servlet implementation class VerSerlvet
 */
@WebServlet("/VerSerlvet")
public class VerSerlvet extends HttpServlet {
	public static String vercode;
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public VerSerlvet() {
        super();
        // TODO Auto-generated constructor stub
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		response.getWriter().append("Served at: ").append(request.getContextPath());
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
	}
	@Override
	protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		response.setHeader("Pragma", "No-cache");  
        response.setHeader("Cache-Control", "no-cache");  
        response.setDateHeader("Expires", 0);  
        response.setContentType("image/jpeg");  
        //生成随机字串  
        String verifyCode = Verification.generateVerifyCode(4);  
        vercode=verifyCode;
        //存入会话session  
        HttpSession session = request.getSession(true);  
        //删除以前的
        session.removeAttribute("verCode");
        session.setAttribute("verCode", verifyCode.toLowerCase());  
        //生成图片  
        int w = 100, h = 30;  
        Verification.outputImage(w, h, response.getOutputStream(), verifyCode);
	
	}

	
}

4.Login.java

package pers.zx.web;

import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import pers.zx.service.PersonService;
import pers.zx.util.PrintUtil;
import pers.zx.util.ReturnResult;
import pers.zx.util.Verification;

/**
 * Servlet implementation class Login
 */
@SuppressWarnings("serial")
@WebServlet(urlPatterns = { "/Login" }, name = "Login")
public class Login extends HttpServlet {

	//private String ver;
	@SuppressWarnings("rawtypes")
	public Class getServletClass(){
		return Login.class;
	}
	 @Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doPost(req,resp);
		 //resp.getWriter().append("Served at: ").append(req.getContextPath());
	}

	@SuppressWarnings("unchecked")
	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		// TODO Auto-generated method stub
		
		 String actionIndicator = req.getParameter("action");//获取servlet返回的字符串特指action
		 Method method = null;
	      //  Object result = null;
	      
            try {
            	//获取该类所需求的方法,这里指获取check方法
				method = getServletClass().getDeclaredMethod(actionIndicator, HttpServletRequest.class, HttpServletResponse.class);
				//执行方法
				method.invoke(this, req, resp);//方法实现，调用Login类里面的check方法	
			} catch (NoSuchMethodException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			} catch (SecurityException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			} catch (IllegalAccessException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			} catch (IllegalArgumentException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			} catch (InvocationTargetException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
           
	}

	/**
     * 登陆的方法
     * @param request
     * @return
     */
public ReturnResult check(HttpServletRequest request, HttpServletResponse response) {
	    ReturnResult result=new ReturnResult();
	    VerSerlvet v=new VerSerlvet();
		boolean flag=false;
		String name=request.getParameter("name");
		String password=request.getParameter("password");
		String verificate=request.getParameter("verificate");
		PersonService per=new PersonService();
		flag=per.check(name, password);
		System.out.println(name);
		String ver=v.vercode;
		
		if(ver.toLowerCase().equals(verificate.toLowerCase())) {//不受大小写的的限制，toLower是将大写字母变为小写
			if(flag==true) {

				result.returnSuccess("登陆成功");
				 PrintUtil.write(result, response);//向ajax传值
			}else {
				result.returnFail("登陆失败");
				 PrintUtil.write(result, response);
				 
			}
		}else {
			result.returnFail("验证码错误");
			 PrintUtil.write(result, response);
		}
		  
		return result;
	}

      
}

三、结果显示

注:

所做的分析都是笔者自己的见解，如有不正确还请见谅。
另外，如需代码请访问我的Github：https://github.com/Zxnaruto