web實現圖形驗證碼功能

jopen 12年前發布 | 12K 次閱讀驗證碼驗證碼(Captcha)

這里直接上工程文件源碼：

web實現圖形驗證碼功能

ValidateImage.java:

package jpeg;

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

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGEncodeParam;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

public class ValidateImage extends HttpServlet {

    protected void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException{
        response.setContentType("image/jpeg");
        createImage(response.getOutputStream());
        response.setHeader("Pragma","No-cache");
        response.setHeader("Cache-Control","no-cache");
        response.setDateHeader("Expires", 0);
    }

    private void createImage(OutputStream out)throws IOException    {
        int width=60, height=20;
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        Graphics g = image.getGraphics();
        Random random = new Random();
        g.setColor(getRandColor(200,250));
        g.fillRect(0, 0, width, height);
        g.setFont(new Font("Times New Roman",1,15));
        //g.setColor(new Color());
        //g.drawRect(0,0,width-1,height-1);
        g.setColor(getRandColor(160,200));
        for (int i=0;i<155;i++){
            int x = random.nextInt(width);
            int y = random.nextInt(height);
                int xl = random.nextInt(12);
                int yl = random.nextInt(12);
            g.drawLine(x,y,x+xl,y+yl);
        }
        //String rand = request.getParameter("rand");
        //rand = rand.substring(0,rand.indexOf("."));
        String sRand="";
        for (int i=0;i<4;i++){
            String rand=String.valueOf(random.nextInt(10));
            sRand+=rand;
            g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));
            g.drawString(rand,13*i+6,16);
        }
              //session.setAttribute("rand",sRand);
        g.dispose();
        JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
        JPEGEncodeParam param   = encoder.getDefaultJPEGEncodeParam(image);
        param.setQuality(1.0f, false);
        encoder.setJPEGEncodeParam(param);
        try{
            encoder.encode(image);
        }catch (IOException ioe){
            ioe.printStackTrace();
        }
    }

    Color getRandColor(int fc,int bc){
        Random random = new Random();
        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);
        }

}

TestImage.jsp:

  <body>
    <img src="validate"> <br>
  </body>

web.xml:

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" 
    xmlns="http://java.sun.com/xml/ns/javaee" 
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
    http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
  <servlet>
    <description>This is the description of my J2EE component</description>
    <display-name>This is the display name of my J2EE component</display-name>
    <servlet-name>ValidateImage</servlet-name>
    <servlet-class>jpeg.ValidateImage</servlet-class>
  </servlet>

  <servlet-mapping>
    <servlet-name>ValidateImage</servlet-name>
    <url-pattern>/validate</url-pattern>
  </servlet-mapping>
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
</web-app>

地址欄：http://localhost:8080/JPEG/jsp/TestImage.jsp 結果：