Java制作验证码的完整实例代码

Java制作验证码的完整实例代码

java代码制作验证码，可用于注册等功能页面

要导入servlet-api.jar包

创建验证码的Util工具类：

先创建图片并生成随机的验证码字母

设置图片的底色，并用setFont函数将验证码画在图片上，如果想让验证码难一点，可以添加for循环的代码给图片增加旋转角度

给验证码增加干扰线，提高安全性

设置边框

创建VerifyPic的servlet，通过Util类获取代码，并存入session中，然后输送去前端页面

前端页面验证码如下：

完整Util工具类代码如下：

package com.sport.util;

import java.awt.*;

import java.awt.image.BufferedImage;

import java.util.HashMap;

import java.util.Map;

public class VerifyUtil {

public static Map generateVerify(){

//创建一张图片

BufferedImage verifyPic = new BufferedImage(120,40,BufferedImage.TYPE_3BYTE_BGR);

//通过图片获取画笔

Graphics2D g = verifyPic.createGraphics();

//准备一个字母+数字的字典

String letters = "23456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";

//规定验证码的位数

int verifyLength = 4;

//生成随机验证码

String verifyCode = "";

//循环取值

for(int i=0; i

verifyCode +=letters.charAt((int)(Math.random()*letters.length()));

}

//将图片的底板由黑变白

g.setColor(Color.white);

g.fillRect(0, 0, 120, 40);

//将验证码画在图片之上

g.setFont(new Font("微软雅黑",Font.BOLD, 24));

for (int i = 0; i < verifyLength; i++) {

//随机产生一个角度

double theta = Math.random() * Math.PI / 4 * ((int)(Math.random()*2) == 0?1:-1);

//产生偏转

g.rotate(theta, 24+i*22, 20);

//每画一个字幕之前都随机给一个颜色

g.setColor(new Color((int)(Math.random()*256), (int)(Math.random()*256), (int)(Math.random()*256)));

g.drawString(verifyCode.charAt(i)+"", 20+i*22 , 26);

//回正

g.rotate(-theta, 24+i*22, 20);

}

//加入干扰线

for (int i = 0; i < 5; i++) {

//给随机颜色

g.setColor(new Color((int)(Math.random()*256), (int)(Math.random()*256), (int)(Math.random()*256)));

//画线

g.drawLine((int)(Math.random()*120), (int)(Math.random()*40),

(int)(Math.random()*120), (int)(Math.random()http://*40));

}

//设置边框颜色

g.setColor(Color.black);

//给验证码一个外边框

g.drawRect(0, 0, 118, 38);

//IqfcJl将验证码和图片一起存入map

Map data = new HashMap();

data.put("verifyCode", verifyCode);

data.put("verifyPic", verifyPic);

return data;

}

}

完整VerifyPic的代码如下：

package com.sport.servlet;

import com.sport.util.VerifyUtil;

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.HttpSehttp://rvletResponse;

import javax.servlet.http.HttpSession;

import java.awt.image.BufferedImage;

import java.io.IOException;

import java.util.Map;

@WebServlet("/VerifyPic")

public class VerifyPic extends HttpServlet {

protected void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

Map data = VerifyUtil.generateVerify();

//获取验证码

String verifyCode = (String) data.get("verifyCode");

//将验证码存入session

HttpSession session = request.getSession();

session.setAttribute("verifyCode", verifyCode);

//获取图片

BufferedImage verifyPic = (BufferedImage) data.get("verifyPic");

//输出图片给前端，使用工具类ImageIO

ImageIO.write(verifyPic, "jpg", response.getOutputStream());

}

protected void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

doGet(request, response);

}

}

总结

verifyCode +=letters.charAt((int)(Math.random()*letters.length()));

}

//将图片的底板由黑变白

g.setColor(Color.white);

g.fillRect(0, 0, 120, 40);

//将验证码画在图片之上

g.setFont(new Font("微软雅黑",Font.BOLD, 24));

for (int i = 0; i < verifyLength; i++) {

//随机产生一个角度

double theta = Math.random() * Math.PI / 4 * ((int)(Math.random()*2) == 0?1:-1);

//产生偏转

g.rotate(theta, 24+i*22, 20);

//每画一个字幕之前都随机给一个颜色

g.setColor(new Color((int)(Math.random()*256), (int)(Math.random()*256), (int)(Math.random()*256)));

g.drawString(verifyCode.charAt(i)+"", 20+i*22 , 26);

//回正

g.rotate(-theta, 24+i*22, 20);

}

//加入干扰线

for (int i = 0; i < 5; i++) {

//给随机颜色

g.setColor(new Color((int)(Math.random()*256), (int)(Math.random()*256), (int)(Math.random()*256)));

//画线

g.drawLine((int)(Math.random()*120), (int)(Math.random()*40),

(int)(Math.random()*120), (int)(Math.random()http://*40));

}

//设置边框颜色

g.setColor(Color.black);

//给验证码一个外边框

g.drawRect(0, 0, 118, 38);

//IqfcJl将验证码和图片一起存入map

Map data = new HashMap();

data.put("verifyCode", verifyCode);

data.put("verifyPic", verifyPic);

return data;

}

}

完整VerifyPic的代码如下：

package com.sport.servlet;

import com.sport.util.VerifyUtil;

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.HttpSehttp://rvletResponse;

import javax.servlet.http.HttpSession;

import java.awt.image.BufferedImage;

import java.io.IOException;

import java.util.Map;

@WebServlet("/VerifyPic")

public class VerifyPic extends HttpServlet {

protected void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

Map data = VerifyUtil.generateVerify();

//获取验证码

String verifyCode = (String) data.get("verifyCode");

//将验证码存入session

HttpSession session = request.getSession();

session.setAttribute("verifyCode", verifyCode);

//获取图片

BufferedImage verifyPic = (BufferedImage) data.get("verifyPic");

//输出图片给前端，使用工具类ImageIO

ImageIO.write(verifyPic, "jpg", response.getOutputStream());

}

protected void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

doGet(request, response);

}

}

总结

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