使用JAVA生成四位随机验证码图片

效果：是第一位和第三位是随机数字，第二位和第四位是随机字母，图片中还有随机干扰线，这些数字，字母，干扰线的颜色均随机

package cn.itcast.web.response;

import java.awt.Color;

import java.awt.Font;

import java.awt.Graphics;

import java.awt.image.BufferedImage;

import java.awt.image.BufferedImageOp;

import java.io.IOException;

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;

//生成验证码图片

public class Demo1 extends HttpServlet {

public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {

int WIDTH = 100;

int HIGHT = 30;

//在内在中创建一幅图片

BufferedImage image = new BufferedImage(WIDTH,HIGHT,BufferedImage.TYPE_INT_RGB); //取得一个画笔

Graphics g = image.getGraphics();

//设置字符串格式

g.setFont(new Font("黑体",Font.BOLD,24));

//画干扰线

for(int i=0;i<7;i++){

Random r = new Random();

int x1 = r.nextInt(WIDTH);

int x2 = r.nextInt(WIDTH);

int y1 = r.nextInt(HIGHT);

int y2 = r.nextInt(HIGHT);

Color color = new Color(

(new Double(Math.random() * 128)).intValue() + 128,

(new Double(Math.random() * 128)).intValue() + 128,

(new Double(Math.random() * 128)).intValue() + 128);

g.setColor(color);

g.drawLine(x1, y1, x2, y2);

import java.util.*;//导入java.util包下的类

public class JavaDemo10

{

public static void main(String args[])

{

String str = "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";

String str2[] = str.split(",");//将字符串以,分割

int sum = 0;//计数器

for (int i=0; i

{

++sum;

if (0 == sum % 10)

{

System.out.println("");//没十个数据换行

}

System.out.print(str2[i] + " ");

}

System.out.println("");

Random rand = new Random();//创建Random类的对象rand

int index = 0;

String randStr = "";//创建内容为空字符串对象randStr

Scanner scan = new Scanner(System.in);//创建Scanner类的对象

while (!scan.next().equals("#"))//判断从键盘输入的是否是字符#

{

randStr = "";//清空字符串对象randStr中的值

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

{

index = rand.nextInt(str2.length-1);//在0到str2.length-1生成一个伪随机数赋值给index

randStr += str2[index];//将对应索引的数组与randStr的变量值相连接

}

System.out.println("验证码：" + randStr);//输出所求的验证码的值

}

}

/*

*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

*a

*验证码：u8rg

*#

*

* */

}