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Servlet（七）生成验证码

2024-08-02 11:40:36   218人阅读

1、ImageCode.java

package com.hunhun.utils;

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.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;


/**
 * Servlet implementation class ImageCode
 */
@WebServlet("/ImageCode")
public class ImageCode extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public ImageCode() {
        super();
        // TODO Auto-generated constructor stub
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		//禁止浏览器缓存随机图片
		response.setDateHeader("Expires", -1);
		response.setHeader("Cache-Control", "no-cache");
		response.setHeader("Pragma", "no-cache");
		//通知浏览器以图片方式显示数据
		response.setHeader("Content-Type", "image/png");
		//在内存中创建图片
		BufferedImage image = new BufferedImage(75,20,BufferedImage.TYPE_INT_RGB);
		//获取图片上下文  
		Graphics g = image.getGraphics();
		//设置背景色
		  g.setColor(Color.black);
		  g.fillRect(0, 0, 75, 20);
		  //生成随机类
		  Random r = new Random();
		  //生成4位验证码
		  String srcChars ="abcdefghijklmnopqrstuvwxyz1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ";
		  String number = "";
		  for(int i=0;i<4;i++){
		   number +=srcChars.charAt(r.nextInt(srcChars.length()));
		  }
		  //设置字体、颜色
		  g.setFont(new Font("Arial",Font.BOLD|Font.ITALIC,16));//new Font(name, style, size)
		  g.setColor(new Color(r.nextInt(255),r.nextInt(255),r.nextInt(255)));
		// 随机产生15条干扰线，使图象中的认证码不易被其它程序探测到  
	        for (int i = 0; i < 15; i++) {  
	            int x = r.nextInt(75);  
	            int y = r.nextInt(20);  
	            int xl = r.nextInt(12);  
	            int yl = r.nextInt(12);  
	            g.drawLine(x, y, x + xl, y + yl);  
	        }  
	        g.setColor(new Color(r.nextInt(255),r.nextInt(255),r.nextInt(255)));
		  g.drawString(number,10,15);
		  //保存session
		  request.getSession().setAttribute("code",number);
		  OutputStream os = response.getOutputStream();
		  ImageIO.write(image, "png", os);
		  
		//  JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(os);
		//  encoder.encode(image);
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		this.doGet(request, response);
	}

}

2.login.jsp

<%@ page language="java" contentType="text/html; charset=utf-8"
    pageEncoding="utf-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Insert title here</title>
</head>
<body>
<form action="/LittleMall/LoginCServlet" method="post">
<input type="text" name="code" value=http://www.mamicode.com/"">code
>

图片样式：


Servlet（七）生成验证码


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