代码.图片验证码

Posted jeeskill

tags:

篇首语：本文由小常识网(cha138.com)小编为大家整理，主要介绍了代码.图片验证码相关的知识，希望对你有一定的参考价值。

1、环境：Win7x64、eclipse-jee-mars-R-win32__apk__20180122_1457、JDK1.8

 

2、知识点：

　（1）、Session 使用

　　ZC：貌似使用 很简单... request.getSession() 貌似获取的就是 本request关联的Session，这样 就不需要再弄 Map之类的来关联了，直接用就行了...

　（2）、Cookie使用

　　看到 "test_yzm.html"和"TservletLogon"中 有 获取 和 设置(通过response相应头来设置)  Cookie的方式

　（3）、动态图片验证码

　　"3.4"里面的就是 验证码相关的 代码

 

3、代码：

　3.1、test_yzm.html

<%@ page language="java" contentType="text/html; charset=utf-8"
    pageEncoding="utf-8"%>
<!DOCTYPE html>

<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
    <title>测试图片验证码</title>
</head>
<body>

<%
// JavaWeb实现登录验证码 - 梦蓝樱飞(一点一滴, 记录个人成长之路) - CSDN博客.html（https://blog.csdn.net/menglanyingfei/article/details/79101580）

    String ContextPath = request.getContextPath();
    //String message = request.getParameter("message");
    //String imageMess = request.getParameter("imageMess");
    //String error = request.getParameter("error");
    
    String message = (String)request.getAttribute("message");
    String imageMess = (String)request.getAttribute("imageMess");
    String error = (String)request.getAttribute("error");
    
    System.out.println("JSP- message : "+message);
    System.out.println("JSP- imageMess : "+imageMess);
    System.out.println("JSP- error : "+error);
    

    // 获取浏览器发送过来的cookie, 获取用户信息
    Cookie[] cookies = request.getCookies();
    String username = "";
    if (cookies != null)
    {
        for (Cookie cookie : cookies)
        {
            if ("username".equals(cookie.getName()))
                username = cookie.getValue();
        }
    }
%>

    <font color="red"><%= message%></font>
    <form action="<%= ContextPath%>/servletLogon" method="post">
        用户名:<input type="text" name="username" value="<%= username%>"><font color="red"><%= error%></font><br>
        密码:<input type="password" name="password"><br>
        验证码:<input type="text" name="image">
        <img src="<%= ContextPath%>/servletVerifyCode"><input type="button" value="看不清? 换一张." id="btnVerifyCode"><font color="red"><%= imageMess%></font><br>
        <input type="submit" value="登录">
    </form>

    <script type="text/javascript">
        document.getElementById("btnVerifyCode").onclick = function()
        {
            // 获取img元素
            // 为了让浏览器发送请求到servlet, 所以一定要改变src
            document.getElementsByTagName("img")[0].src = "<%= ContextPath%>/servletVerifyCode?time=" + (new Date()).getTime();
        };
    </script>

</body>
</html>

　3.2、TservletLogon.java

package zzz.servlet;

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

@WebServlet("/servletLogon")
public class TservletLogon extends HttpServlet
{
    private static final long serialVersionUID = 1L;

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
    {
//        response.getWriter().append("Served at: ").append(request.getContextPath());
        
        System.out.println("image : " + request.getParameter("image"));
        System.out.println("username : " + request.getParameter("username"));
        System.out.println("password : " + request.getParameter("password"));
        System.out.println("");
        
        String imageText = request.getParameter("image");
        // 图片的验证码
        String text = (String) request.getSession().getAttribute("text");
        System.out.println("text : " + text);

        if (! text.equalsIgnoreCase(imageText))
        {
            request.setAttribute("imageMess", "验证码输入错误!");
            request.getRequestDispatcher("/test_yzm.jsp").forward(request, response);
            return;
        }
        // 获取用户名和密码
        String username = request.getParameter("username");
        String password = request.getParameter("password");

        if ("haha".equals(username) && "123".equals(password))
        {
            // 将用户信息保存到session中
            request.getSession().setAttribute("username", username);

            // 使用cookie实现回写用户名
            Cookie cookie = new Cookie("username", username);
            cookie.setMaxAge(60 * 60);
            // 通过响应头发送cookie
            response.addCookie(cookie);

            // 重定向登录成功界面
            response.sendRedirect( request.getContextPath() + "/logOK.jsp" );
        }
        else
        {
            request.setAttribute("error", "用户名或密码错误!");
            request.getRequestDispatcher("/test_yzm.jsp").forward(request, response);
        }
    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
    {
        doGet(request, response);
    }

}

　3.3、logOK.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>登录 成功</title>
</head>
<body>
登录 成功
</body>
</html>

　3.4、图片 验证码 相关

　　（1）TservletVerifyCode.java

package zzz.servlet;

import java.awt.image.BufferedImage;
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 wx.VerifyCode.TverifyCode;

@WebServlet("/servletVerifyCode")
public class TservletVerifyCode extends HttpServlet
{
    private static final long serialVersionUID = 1L;

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
    {
//        response.getWriter().append("Served at: ").append(request.getContextPath());
        
        //创建对象
        TverifyCode vc = new TverifyCode();
        //获取图片对象
        BufferedImage bi = vc.getImage();
        //获得图片的文本内容
        String text = vc.getText();
        // 将系统生成的文本内容保存到session中
        request.getSession().setAttribute("text", text);
        //向浏览器输出图片
        TverifyCode.output(bi, response.getOutputStream());
    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
    {
        doGet(request, response);
    }

}

　　（2）TverifyCode.java

package wx.VerifyCode;

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;

import javax.imageio.ImageIO;

public class TverifyCode
{
    private int w = 70;
    private int h = 35;
    private Random r = new Random();
    // {"宋体", "华文楷体", "黑体", "华文新魏", "华文隶书", "微软雅黑", "楷体_GB2312"}
    private String[] fontNames = {"宋体", "华文楷体", "黑体", "微软雅黑", "楷体_GB2312"};
    // 可选字符
    private String codes = "0123456789abcdefghjkmnopqrstuvwxyzABCDEFGHJKMNPQRSTUVWXYZ";
    // 背景色
    private Color bgColor = new Color(255, 255, 255);
    // 验证码上的文本
    private String text ;

    // 生成随机的颜色
    private Color randomColor()
    {
        int red = r.nextInt(150);
        int green = r.nextInt(150);
        int blue = r.nextInt(150);
        return new Color(red, green, blue);
    }

    // 生成随机的字体
    private Font randomFont()
    {
        int index = r.nextInt(fontNames.length);
        String fontName = fontNames[index];//生成随机的字体名称
        int style = r.nextInt(4);//生成随机的样式, 0(无样式), 1(粗体), 2(斜体), 3(粗体+斜体)
        int size = r.nextInt(5) + 24; //生成随机字号, 24 ~ 28
        return new Font(fontName, style, size);
    }

    // 画干扰线
    private void drawLine(BufferedImage image)
    {
        int num  = 3;//一共画3条
        Graphics2D g2 = (Graphics2D)image.getGraphics();
        for(int i = 0; i < num; i++) {//生成两个点的坐标，即4个值
            int x1 = r.nextInt(w);
            int y1 = r.nextInt(h);
            int x2 = r.nextInt(w);
            int y2 = r.nextInt(h); 
            g2.setStroke(new BasicStroke(1.5F)); 
            g2.setColor(Color.BLUE); //干扰线是蓝色
            g2.drawLine(x1, y1, x2, y2);//画线
        }
    }

    // 随机生成一个字符
    private char randomChar()
    {
        int index = r.nextInt(codes.length());
        return codes.charAt(index);
    }

    // 创建BufferedImage
    private BufferedImage createImage()
    {
        BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB); 
        Graphics2D g2 = (Graphics2D)image.getGraphics(); 
        g2.setColor(this.bgColor);
        g2.fillRect(0, 0, w, h);
        return image;
    }

    // 调用这个方法得到验证码
    public BufferedImage getImage()
    {
        BufferedImage image = createImage();//创建图片缓冲区 
        Graphics2D g2 = (Graphics2D)image.getGraphics();//得到绘制环境
        StringBuilder sb = new StringBuilder();//用来装载生成的验证码文本
        // 向图片中画4个字符
        for(int i = 0; i < 4; i++)  {//循环四次，每次生成一个字符
            String s = randomChar() + "";//随机生成一个字母 
            sb.append(s); //把字母添加到sb中
            float x = i * 1.0F * w / 4; //设置当前字符的x轴坐标
            g2.setFont(randomFont()); //设置随机字体
            g2.setColor(randomColor()); //设置随机颜色
            g2.drawString(s, x, h-5); //画图
        }
        this.text = sb.toString(); //把生成的字符串赋给了this.text
        drawLine(image); //添加干扰线
        return image;       
    }

    // 返回验证码图片上的文本
    public String getText()
    {
        return text;
    }

    // 保存图片到指定的输出流
    public static void output(BufferedImage image, OutputStream out) throws IOException
    {
        ImageIO.write(image, "JPEG", out);
    }
}

 

4、

5、

 


以上是关于代码.图片验证码的主要内容，如果未能解决你的问题，请参考以下文章

纯代码系列：Python实现验证码图片(PIL库经典用法用法，爬虫12306思路)

java 登陆时的验证码怎么做？

代码.图片验证码

JAVA生成验证码代码

Java Web 一次性验证码的代码实现

web 动态随机验证码图片生成最新