java验证码

来源：互联网发布：网络没有上传速度编辑：程序博客网时间：2024/06/06 16:31

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.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class CheckCodeServlet extends HttpServlet {
    
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doPost(request, response);
    
    }
    
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("image/jpeg");
        BufferedImage image = new BufferedImage(124, 28, BufferedImage.TYPE_3BYTE_BGR);//new一个图片
        Graphics pen = image.getGraphics();//得到一个画笔
        pen.setColor(Color.lightGray);//设置画笔的颜色
        pen.fillRect(0, 0, 124, 28);//画一个矩形,可以改变背景颜色
        pen.setFont(new Font("微软雅黑", Font.BOLD, 20));//设置字体
        String checkCode = getStr();//验证码的内容
        request.getSession().setAttribute("yzm", checkCode);//存入session
        for (int i = 0; i < checkCode.length(); i++) {//循环将验证码画如到图片
            pen.setColor(getColors());
            pen.drawString(checkCode.charAt(i)+"", i*22+22, (int)(Math.random()*14+14));
        }
        //随机两个线条
        for (int i = 0; i < (int)(Math.random()*4+1); i++) {
            pen.setColor(getColors());
            pen.drawLine(0, (int)(Math.random()*28), 124, (int)(Math.random()*28));
        }
        //输出图片
        ServletOutputStream sos = response.getOutputStream();
        ImageIO.write(image, "png", sos);
        sos.flush();
        sos.close();
        
    
        
    }
    
    /**
     * 获得随机的验证码
     * @return
     */
    public String getStr(){
        String str = "q,w,e,r,t,y,u,i,o,p,a,s,d,f,g,h,j,k,l,z,x,c,v,b,n,m,1,2,3,4,5,6,7,8,9,0";
        String[] strs = str.split(",");
        String reslut = "";
        for (int i = 0; i < 4; i++) {
            int index = (int) (Math.random()*strs.length);
            reslut+=strs[index];
        }
        return reslut;
    }
    
    /**
     * 获取随机的颜色
     */
    public Color getColors(){
        Random random = new Random();
        int r = random.nextInt(256);
        int g = random.nextInt(256);
        int b = random.nextInt(256);
        return new Color(r, g, b);
    }
    
}

<!--HTML-->
<img src = "CheckCodeServlet"  onclick="changeCode()" id="imgCode"/>

//更换验证码
function changeCode(){
document.getElementById("imgCode").src = "CheckCodeServlet?act="+Math.random();
}

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