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java中验证码源代码 java 验证码

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怎样用java实现验证码 现在许多系统的注册 登录或者发布信息模块都添加的随机验证码功能 就是为了避免自动注册程序或者自动发布程序的使用
验证码实际上就是随机选择一些字符以图片的形式展现在页面上 如果进行提交操作的同时需要将图片上的字符同时提交 如果提交的字符与服务器session保存的不同 则认为提交信息无效 为了避免自动程序分析解析图片 通常会在图片上随机生成一些干扰线或者将字符进行扭曲 增加自动识别验证码的难度
在这里 我们使用java实现验证码
%@ page contentType= image/jpeg import= java awt * java awt image * java util * javax imageio * %
%!
Color getRandColor(int fc int bc){//给定范围获得随机颜色
Random random = new Random();
if(fc ) fc= ;
if(bc ) bc= ;
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);
}
%
%
//设置页面不缓存
response setHeader( Pragma No cache );
response setHeader( Cache Control no cache );
response setDateHeader( Expires );
// 在内存中创建图象
int width= height= ;
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( ));
g fillRect( width height);
//设定字体
g setFont(new Font( Times New Roman Font PLAIN ));
// 随机产生 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( ));
for (int i= ;i ;i)
{
int x = random nextInt(width);
int y = random nextInt(height);
int xl = random nextInt( );
int yl = random nextInt( );
g drawLine(x y x xl y yl);
}
// 取随机产生的认证码( 位数字)
【java中验证码源代码 java 验证码】 String codeList = ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz ;
String sRand= ;
for (int i= ;i ;i){
int a=random nextInt(codeList length() );
String rand=codeList substring(a a);
sRand =rand;
// 将认证码显示到图象中
g setColor(new Color(random nextInt( )random nextInt( )random nextInt( )));//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 *i);
}
// 将认证码存入SESSION
session setAttribute( rand sRand);
// 图象生效
g dispose();
// 输出图象到页面
ImageIO write(image JPEG response getOutputStream());
out clear();
out = pageContext pushBody();
lishixinzhi/Article/program/Java/hx/201311/25536
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java中验证码源代码的数组中java中验证码源代码，第1个值是验证码java中验证码源代码，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.BOLDFont.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; iLINES; 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();
}
}
验证码部分的java代码怎么写package com.bbs.servlet;
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.io.PrintWriter;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
public class Image extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("image/jpeg");
OutputStream out = response.getOutputStream();
response.setHeader("Pragma","No-cache");
response.setHeader("Cache-Control","no-cache");
response.setDateHeader("Expires", 0);
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));
// 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(180, 200));
for (int i = 0; i155; 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, xxl, yyl);
}
// 取随机产生的认证码(4位数字)
String sRand =setRandValue(request);
if(sRand!=null)
for (int i = 0; isRand.length(); i) {
g.setColor(new Color(20random.nextInt(200), 20random
.nextInt(200), 20random.nextInt(200)));
// 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(sRand.charAt(i)"", 13 * i6, 16);
}
JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
encoder.encode(image);
// 图象生效
g.dispose();
// 输出图象到页面
// ImageIO.write(image, "JPG", response.getOutputStream());
out.flush();
out.close();
}
Color getRandColor(int fc, int bc) {// 给定范围获得随机颜色
Random random = new Random();
if (fc255)
fc = 255;
if (bc255)
bc = 255;
int r = fcrandom.nextInt(bc - fc);
int g = fcrandom.nextInt(bc - fc);
int b = fcrandom.nextInt(bc - fc);
return new Color(r, g, b);
}
//48-57对应0-9;65-90对应A-Z;97-122对应a-z;
String setRandValue(HttpServletRequest request) {
Random random = new Random();
String sRand = "";
//这里是生成验证码的位数
for (int i = 0; i4; i) {
char c = 0;
int k = random.nextInt(3);
switch (k) {
case 0:
c = (char) (random.nextInt(10)48);
break;
case 1:
c = (char) (random.nextInt(26)65);
break;
case 2:
c = (char) (random.nextInt(26)97);
}
sRand= c;
}
request.getSession().setAttribute("rands", sRand);
return sRand;
}
}
如何用Java代码段生成四位数字加字母的验证码？不知道你问的是不是生成这种图片验证码？如果只要一个随机四位数 那这行代码就够了(new Random().nextInt(9000)1000;),如果是生成页面图片验证码就是下面的了://设定 响应模式resp.setContentType("image/jpeg");// 生成令牌环数据;Integer token = new Random().nextInt(9000)1000;// 保存令牌环数据到session中req.getSession().setAttribute(IMAGE_TOKEN_NAME, token);// 生成令牌环图片ServletOutputStream out = resp.getOutputStream();BufferedImage img = new BufferedImage(60, 20,BufferedImage.TYPE_INT_RGB);Graphics g = img.getGraphics();g.setColor(Color.YELLOW);g.fillRect(0, 0, img.getWidth(), img.getHeight());g.setColor(Color.BLUE);g.setFont(new Font("", Font.BOLD, 18));g.drawString(String.valueOf(token), 10, 16);ImageIO.write(img, "jpg", out);out.close();
下面简单的介绍他们的功能和用途 ， 执行效率等 。每个都有各自的优缺点看你是做甚什么方面的研究开发用 。.net，是网站编程，现在很多都用这个，但是这个语言编程都有统一思路 ， 很好掌握 。窒息那个效率不是很高；php 支持跨平台，很容易学会，执行的效率很高；asp是ASP.net的前身，它比较稳定，比.net要弱一点 。但是比.net好学 。jsp 是网页编程，这个学习大约一周就能搞定，不过这个得多实践，不然的话 ， 时间长了，就容易忘记 。
我自己做的系统里面用作验证码的JSP的%@page contentType="image/jpeg;charset=utf-8"%%@page import="java.util.*,java.awt.*,java.awt.image.*,javax.imageio.*" %%@ page import="java.io.OutputStream" %html body%!Color getRandColor(int fc,int bc){Random rd=new Random();if(fc255) fc=255;if(bc255) bc=255;int red=fc rd.nextInt(bc-fc);int green=fc rd.nextInt(bc-fc);int blue=fc rd.nextInt(bc-fc);return new Color(red,green,blue);}%%Random r=new Random();response.addHeader("Pragma","No-cache");response.addHeader("Cache-Control","no-cache");response.addDateHeader("expires",0);int width=90;int height=23;BufferedImage pic=new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);Graphics gc=pic.getGraphics();gc.setColor(getRandColor(200,250));gc.fillRect(0,0,width,height);String[] rNum ={"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"};int[] style = {Font.PLAIN,Font.BOLD,Font.ITALIC,Font.PLAIN Font.BOLD,Font.BOLD Font.ITALIC,Font.PLAIN Font.ITALIC,Font.PLAIN Font.BOLD Font.ITALIC};gc.setColor(Color.WHITE);gc.drawLine(0,30,90,10);gc.setColor(getRandColor(160,200));for (int i=0;i50;i){int x = r.nextInt(width);int y = r.nextInt(height);int xl = r.nextInt(10);int yl = r.nextInt(10);gc.drawLine(x,y,x xl,y yl);}gc.setColor(getRandColor(60,150));String rt = "";for(int i=0;i4;i){String temp = rNum[r.nextInt(62)];rt = rt temp;gc.setFont(new Font("Times New Roman",style[r.nextInt(7)],15));gc.drawString(temp,5 i*15 r.nextInt(10),10 r.nextInt(10));}gc.dispose();session.setAttribute("randNum",rt);OutputStream os=response.getOutputStream();ImageIO.write(pic,"JPEG",os);System.out.println("当前验证码为:" session.getAttribute("randNum"));os.flush();os.close();os=null;response.flushBuffer();out.clear();out = pageContext.pushBody();% /body/html
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