Javaweb中快速生成验证码Captcha

忘是亡心i 2022-06-15 05:59 502阅读 0赞

**生成验证码的两种方式：**

1.自己手动绘画一个
    
    2.使用插件ValidateCode.jar

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

# **1.自己手动绘画一个验证码** #

**代码演示：**

package com.tcb.servlet;
    
    import java.awt.Color;
    import java.awt.Font;
    import java.awt.Graphics;
    import java.awt.image.BufferedImage;
    import java.io.IOException;
    import java.util.Random;
    
    import javax.imageio.ImageIO;
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import javax.servlet.http.HttpSession;
    
    public class ServletByCaptcha extends HttpServlet {
        
        private static final long serialVersionUID = 1L;
    
        public ServletByCaptcha() {
            super();
        }
    
        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            //1.设置图片的宽高
            int width=120;
            int height=50;
    
            //2.创建图像流对象（画布），以及获得画笔
            BufferedImage image=new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
            Graphics graphics=image.getGraphics();
    
            //3.设置画笔颜色和填充画布（即设置画布背景）
            graphics.setColor(Color.RED);
            graphics.fillRect(0, 0, width, height);
    
            //4.写字前，设置画笔输出的字体    字体类型         粗细/倾斜等       字体大小
            Font font =new Font("微软雅黑", Font.BOLD, 30);
            graphics.setFont(font);
    
            //5.在画布上写字--即生成随机码
            StringBuffer buffer=new StringBuffer();
            Random random=new Random();
    
            //6.循环填写随机码
            for(int i=0;i<4;i++){
                graphics.setColor(Color.GREEN);
                int num=random.nextInt(10);
                //添加随机码
                graphics.drawString(""+num, i*30+10, 40);
                buffer.append(num);
    
                //添加背景斜线
                graphics.setColor(Color.GRAY);
                graphics.drawLine(random.nextInt(width), random.nextInt(height), random.nextInt(width), random.nextInt(height));
            }
    
            //7.将随机码存起了备用           
            HttpSession httpSession=request.getSession();
            httpSession.setAttribute("code", buffer);
    
            //8.输入验证码图片
            ImageIO.write(image, "jpg", response.getOutputStream());
    
        }
    
        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            doGet(request, response);
        }
    
    }

**运行效果图：**

![这里写图片描述][SouthEast]

![这里写图片描述][SouthEast 1]

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

# **2.使用插件生成验证码** #

## **1）实现需要下载一个[ValidateCode.jar][]的jar包。** ##

**下载地址：[http://download.csdn.net/detail/baidu\_37107022/9852253][http_download.csdn.net_detail_baidu_37107022_9852253]**

将下载的jar包，放在当前工程的

WebContent/WEB-INF/lib 的文件名夹下。

**如图：**  
![这里写图片描述][SouthEast 2]

## **2）演示代码如下：** ##

package com.tcb.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 cn.dsna.util.images.ValidateCode;
    
    public class ServletByCaptcha2 extends HttpServlet {
        
        private static final long serialVersionUID = 1L;
    
        public ServletByCaptcha2() {
            super();
        }
    
        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            //1.设置验证码图片的宽高
            int width=120;
            int height=50;
            //2.生成验证码     参数1和2：宽和高       参数3：验证码的位数（一般是4位，比如7RV4，G86T等等）      参数4：干扰线的条数
            ValidateCode code=new ValidateCode(width, height, 4, 10);
            //3.输出验证码图片
            code.write(response.getOutputStream());
    
            //4.将随机码存起了备用 
            String codeString=code.getCode();
            System.out.println("====codeString======"+codeString);
        }
    
        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            doGet(request, response);
        }
    
    }

**运行效果图：**

![这里写图片描述][SouthEast 3]

![这里写图片描述][SouthEast 4]

[SouthEast]: /images/20220615/2cff1adf4724498d9e3965df2035318b.png
[SouthEast 1]: /images/20220615/2b775f0678e34990ae946a4145b5e183.png
[ValidateCode.jar]: http://download.csdn.net/detail/baidu_37107022/9852253%20%E5%BF%AB%E9%80%9F%E7%94%9F%E6%88%90%E9%AA%8C%E8%AF%81%E7%A0%81jar%E5%8C%85
[http_download.csdn.net_detail_baidu_37107022_9852253]: http://download.csdn.net/detail/baidu_37107022/9852253
[SouthEast 2]: /images/20220615/4c066564feb2447a8558754498639514.png
[SouthEast 3]: /images/20220615/1c1d345e27d84c0c9062da62d8e3c925.png
[SouthEast 4]: /images/20220615/e419d59ac0684b40bfb8eab55215dc09.png