javaWeb注册登录页面包含验证码

登录成功：

登录失败：

代码：

（1）主页jsp

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


    
    



"/day16/loginServlet" method="post">
    

        

            
用户名：
            
"text" name="username">
        
        

            
密码：
            
"password" name="password">
        
        

            
验证码：
            
"text" name="checkCode">
        
        


            
"2">"checkCodeServlet" id="img">
        
        


            
"2">"submit" value="登录">
        
    

<%=request.getAttribute("cc_error") == null ? "" : request.getAttribute("cc_error")%>
<%=request.getAttribute("login_error") == null ? "" : request.getAttribute("login_error") %>

（2）生成验证码（图片）：

package cn.itcase.servlet;



import javax.imageio.ImageIO;
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 java.awt.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;

@WebServlet("/checkCodeServlet")
public class checkCodeServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //1.创建对象，在内存中图片（验证码图片对象）

        int width=100;
        int height=50;

        BufferedImage image=new BufferedImage(width,height,BufferedImage.TYPE_3BYTE_BGR);



        //2.美化图片
        //2.1填充背景色
        Graphics graphics = image.getGraphics();//画笔对象
        graphics.setColor(Color.PINK);//画笔的颜色
        graphics.fillRect(0,0,width,height);//fillRect方法可以画背景颜色
        //2.2画边框
        graphics.setColor(Color.red);
        graphics.drawRect(0,0,width-1, height-1);//drawRect方法可以画边框
        //2.3写验证码
        String str="qytwujfhafkYUIPASDFGHLZXCiVBNM23456789";
        StringBuilder sb=new StringBuilder();

        Random random=new Random();        //创建随机对象
        for (int i = 1; i <=4; i++) {         //循环4次，产生4位的验证码
            int index=random.nextInt(str.length());        //生成角标
            char ch=str.charAt(index);
            sb.append(ch);
            //随机字符
            graphics.drawString(ch+"",width/5*i,height/2);//验证码

        }
        String checkCode_session = sb.toString();
        //将验证码存入session
        request.getSession().setAttribute("checkCode_session" ,checkCode_session);
        //2.4画干扰线
        graphics.setColor(Color.green);
        for (int i = 0; i <10; i++) {
            int x1=random.nextInt(width);
            int x2=random.nextInt(width);
            int y1=random.nextInt(height);
            int y2=random.nextInt(height);
            graphics.drawLine(x1,x2,y1,y2);
        }


        //3.输出图片（字符输出流）
        ImageIO.write(image,"jpg",response.getOutputStream());



    }

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

（3)登录成功页面代码:

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


    


<%=request.getSession().getAttribute("user")  %>,欢迎您！