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java实现点击图片文字验证码,java图片验证码工具类

时间：2023-12-27 22:26:51 阅读：325048 作者：SLUI

本文目录一览：

用java怎么制作验证码

原理:

1.随机生成4个数字 用到了Random类

2.对这4个数字设置字体格式 用 setFont方法

3.改变字体颜色用setColor 然后随机生成颜色

代码如下

package s1;

import java.awt.Color;

import java.awt.Font;

import java.awt.Graphics;

import java.awt.image.BufferedImage;

import java.io.IOException;

import java.io.PrintWriter;

import java.util.Random;

import javax.imageio.ImageIO;

import javax.jms.Session;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;

public class GetImage extends HttpServlet {

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

this.doPost(request, response);

}

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

// 发送图片不能够添加这2行代码

// response.setContentType("text/html;charset=UTF-8");

// request.setCharacterEncoding("UTF-8");

int width=100;

int height=50;

//获得一张图片

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

Graphics g=image.getGraphics();

g.setColor(Color.WHITE);

g.fillRect(1, 1, width-2, height-2);

g.setFont(new Font("宋体",Font.BOLD,30));

Random random=new Random();

// 填充的字符串

String str="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";

//缓存生成的验证码

StringBuffer stringbuffer=new StringBuffer();

//随机生成验证码的颜色和字符

for(int i=0;i4;i++)

{ //设置随机颜色

g.setColor(new Color(random.nextInt(256), random.nextInt(256), random.nextInt(256)));

int index=random.nextInt(62);//这里的62就是从填充字符段中随意选取一个位置

String str1=str.substring(index,index+1);

g.drawString(str1, 20*i, 30);//x,y数值设置太小会显示不出来

stringbuffer.append(str1);

}

//将生成的验证码存到服务器

request.getSession().setAttribute("checkcode", stringbuffer.toString());//key和value

//将图片发送给浏览器

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

}

}

用户登录界面代码

package s1;

import java.io.IOException;

import java.io.PrintWriter;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;

public class Login extends HttpServlet {

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

}

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

response.setContentType("text/html;charset=UTF-8");// 设置服务器发送给浏览器的编码方式

request.setCharacterEncoding("UTF-8"); // 客户端向服务器提交的数据的解码方式

// 获得用户提交的数据

String checkcode = request.getParameter("checkcode");

System.out.println(checkcode);

// 判断输入的验证码是不是符合

HttpSession session = request.getSession();// session是存放数据的地方

String str = (String) session.getAttribute("checkcode");

if (str != null) {

if (checkcode.compareToIgnoreCase(str) == 0) // 验证码忽略大小写

response.getWriter().println("验证码输入正确");

else

response.getWriter().println("验证码输入错误");

}

else response.getWriter().println("验证码失效");

// 使用完的验证码信息要删除,返回原页面再输一次,验证码就失效了

session.removeAttribute("checkcode");

}

}

怎么用Java代码实现一个验证码，求具体实现方法

package util;

import java.awt.Color;

import java.awt.Font;

import java.awt.Graphics;

import java.awt.image.BufferedImage;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.OutputStream;

import java.util.Random;

import javax.imageio.ImageIO;

public final class ImageUtil {

    

    // 验证码字符集

    private static final char[] chars = { 

        '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 

        'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 

        'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 

        'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 

        'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'};

    // 字符数量

    private static final int SIZE = 4;

    // 干扰线数量

    private static final int LINES = 5;

    // 宽度

    private static final int WIDTH = 80;

    // 高度

    private static final int HEIGHT = 40;

    // 字体大小

    private static final int FONT_SIZE = 30;

    /**

     * 生成随机验证码及图片

     * 返回的数组中，第1个值是验证码，第2个值是图片

     */

    public static Object[] createImage() {

        StringBuffer sb = new StringBuffer();

        // 1.创建空白图片

        BufferedImage image = new BufferedImage(

            WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);

        // 2.获取图片画笔

        Graphics graphic = image.getGraphics();

        // 3.设置画笔颜色

        graphic.setColor(Color.LIGHT_GRAY);

        // 4.绘制矩形背景

        graphic.fillRect(0, 0, WIDTH, HEIGHT);

        // 5.画随机字符

        Random ran = new Random();

        for (int i = 0; i SIZE; i++) {

            // 取随机字符索引

            int n = ran.nextInt(chars.length);

            // 设置随机颜色

            graphic.setColor(getRandomColor());

            // 设置字体大小

            graphic.setFont(new Font(

                null, Font.BOLD + Font.ITALIC, FONT_SIZE));

            // 画字符

            graphic.drawString(

                chars[n] + "", i * WIDTH / SIZE, HEIGHT / 2);

            // 记录字符

            sb.append(chars[n]);

        }

        // 6.画干扰线

        for (int i = 0; i  LINES; i++) {

            // 设置随机颜色

            graphic.setColor(getRandomColor());

            // 随机画线

            graphic.drawLine(ran.nextInt(WIDTH), ran.nextInt(HEIGHT),

                    ran.nextInt(WIDTH), ran.nextInt(HEIGHT));

        }

        // 7.返回验证码和图片

        return new Object[]{sb.toString(), image};

    }

    /**

     * 随机取色

     */

    public static Color getRandomColor() {

        Random ran = new Random();

        Color color = new Color(ran.nextInt(256), 

                ran.nextInt(256), ran.nextInt(256));

        return color;

    }

    

    public static void main(String[] args) throws IOException {

        Object[] objs = createImage();

        BufferedImage image = (BufferedImage) objs[1];

        OutputStream os = new FileOutputStream("d:/1.png");

        ImageIO.write(image, "jpeg", os);

        os.close();

    }

}

怎样用java实现验证码

package com.servlet;

import java.awt.*;

import java.awt.geom.*;

import java.awt.image.*;

import java.io.*;

import java.util.*;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;

import javax.imageio.ImageIO;

public class PictureCheckCode extends HttpServlet {

private static final long serialVersionUID = 1L;

public PictureCheckCode() {

super();

}

public void destroy() {

super.destroy();

}

public void init() throws ServletException {

super.init();

}

/*该方法主要作用是获得随机生成的颜色*/

public Color getRandColor(int s,int e){

Random random=new Random ();

if(s255) s=255;

if(e255) e=255;

int r,g,b;

r=s+random.nextInt(e-s); //随机生成RGB颜色中的r值

g=s+random.nextInt(e-s); //随机生成RGB颜色中的g值

b=s+random.nextInt(e-s); //随机生成RGB颜色中的b值

return new Color(r,g,b);

}

@Override

public void service(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

//设置不缓存图片

response.setHeader("Pragma", "No-cache");

response.setHeader("Cache-Control", "No-cache");

response.setDateHeader("Expires", 0);

//指定生成的响应图片,一定不能缺少这句话,否则错误.

response.setContentType("image/jpeg");

int width=86,height=22; //指定生成验证码的宽度和高度

BufferedImage image=new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB); //创建BufferedImage对象,其作用相当于一图片

Graphics g=image.getGraphics(); //创建Graphics对象,其作用相当于画笔

Graphics2D g2d=(Graphics2D)g; //创建Grapchics2D对象

Random random=new Random();

Font mfont=new Font("楷体",Font.BOLD,16); //定义字体样式

g.setColor(getRandColor(200,250));

g.fillRect(0, 0, width, height); //绘制背景

g.setFont(mfont); //设置字体

g.setColor(getRandColor(180,200));

//绘制100条颜色和位置全部为随机产生的线条,该线条为2f

for(int i=0;i100;i++){

int x=random.nextInt(width-1);

int y=random.nextInt(height-1);

int x1=random.nextInt(6)+1;

int y1=random.nextInt(12)+1;

BasicStroke bs=new BasicStroke(2f,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL); //定制线条样式

Line2D line=new Line2D.Double(x,y,x+x1,y+y1);

g2d.setStroke(bs);

g2d.draw(line); //绘制直线

}

//输出由英文，数字，和中文随机组成的验证文字，具体的组合方式根据生成随机数确定。

String sRand="";

String ctmp="";

int itmp=0;

//制定输出的验证码为四位

for(int i=0;i4;i++){

switch(random.nextInt(3)){

case 1: //生成A-Z的字母

itmp=random.nextInt(26)+65;

ctmp=String.valueOf((char)itmp);

break;

case 2: //生成汉字

String[] rBase={"0","1","2","3","4","5","6","7","8","9","a","b","c","d","e","f"};

//生成第一位区码

int r1=random.nextInt(3)+11;

String str_r1=rBase[r1];

//生成第二位区码

int r2;

if(r1==13){

r2=random.nextInt(7);

}else{

r2=random.nextInt(16);

}

String str_r2=rBase[r2];

//生成第一位位码

int r3=random.nextInt(6)+10;

String str_r3=rBase[r3];

//生成第二位位码

int r4;

if(r3==10){

r4=random.nextInt(15)+1;

}else if(r3==15){

r4=random.nextInt(15);

}else{

r4=random.nextInt(16);

}

String str_r4=rBase[r4];

//将生成的机内码转换为汉字

byte[] bytes=new byte[2];

//将生成的区码保存到字节数组的第一个元素中

String str_12=str_r1+str_r2;

int tempLow=Integer.parseInt(str_12, 16);

bytes[0]=(byte) tempLow;

//将生成的位码保存到字节数组的第二个元素中

String str_34=str_r3+str_r4;

int tempHigh=Integer.parseInt(str_34, 16);

bytes[1]=(byte)tempHigh;

ctmp=new String(bytes);

break;

default:

itmp=random.nextInt(10)+48;

ctmp=String.valueOf((char)itmp);

break;

}

sRand+=ctmp;

Color color=new Color(20+random.nextInt(110),20+random.nextInt(110),random.nextInt(110));

g.setColor(color);

//将生成的随机数进行随机缩放并旋转制定角度 PS.建议不要对文字进行缩放与旋转,因为这样图片可能不正常显示

/*将文字旋转制定角度*/

Graphics2D g2d_word=(Graphics2D)g;

AffineTransform trans=new AffineTransform();

trans.rotate((45)*3.14/180,15*i+8,7);

/*缩放文字*/

float scaleSize=random.nextFloat()+0.8f;

if(scaleSize1f) scaleSize=1f;

trans.scale(scaleSize, scaleSize);

g2d_word.setTransform(trans);

g.drawString(ctmp, 15*i+18, 14);

}

HttpSession session=request.getSession(true);

session.setAttribute("randCheckCode", sRand);

g.dispose(); //释放g所占用的系统资源

ImageIO.write(image,"JPEG",response.getOutputStream()); //输出图片

}

}

JAVA识别图片验证码

package com.he;

import javax.servlet.*;

import javax.servlet.http.*;

import java.io.*;

import java.util.*;

import java.awt.*;

import java.awt.image.*;

import javax.imageio.*;

public class CodeFact

extends HttpServlet {

public void doGet(HttpServletRequest request, HttpServletResponse response) throws

ServletException, IOException {

//设置页面不缓存

response.setHeader("Pragma", "No-cache");

response.setHeader("Cache-Control", "no-cache");

response.setDateHeader("Expires", 0);

// 在内存中创建图象

int width = 60, height = 20;

BufferedImage image = new BufferedImage(width, height,

BufferedImage.TYPE_INT_RGB);

// 获取图形上下文

Graphics g = image.getGraphics();

//生成随机类

Random random = new Random();

// 设定背景色

g.setColor(getRandColor(200, 250));

g.fillRect(0, 0, width, height);

//设定字体

g.setFont(new Font("Times New Roman", Font.PLAIN, 18));

//画边框

g.setColor(new Color(33,66,99));

g.drawRect(0,0,width-1,height-1);

// 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到

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);

}

// 取随机产生的认证码(4位数字)

String sRand = "";

for (int i = 0; i 4; i++) {

String rand = String.valueOf(random.nextInt(10));

sRand += rand;

// 将认证码显示到图象中

g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110),

20 + random.nextInt(110))); //调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成

g.drawString(rand, 13 * i + 6, 16);

}

// 将认证码存入SESSION

HttpSession session = request.getSession();

session.setAttribute("rand", sRand);

// 图象生效

g.dispose();

// 输出图象到页面

ImageIO.write(image, "JPEG", response.getOutputStream());

}

public void doPost(HttpServletRequest request, HttpServletResponse response) throws

ServletException, IOException {

doGet(request, response);

}

//给定范围获得随机颜色

private 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);

}

}

你试试！！

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