生成不同类型的验证码类

package com.datatang.utils;


import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.imageio.stream.ImageOutputStream;


/**
 * 验证码类，主要生成几种不同类型的验证码 第一种：简单验证码，4位随机数字 第二种：英文字符加数字的验证码 第三种：像铁路订票系统一样的验证码，肆+？=21
 * 
 */
public class VerifyCode {
/** 图像 */
private ByteArrayInputStream image;
/** 验证码 */
private String code;
private static final int WIDTH = 80;
private static final int HEIGHT = 20;


private static VerifyCode instance = null;


public static void main(String[] arg) {
VerifyCode vcu = VerifyCode.Instance();
System.err.println(vcu.getVerificationCodeValue());
}


/**
* 功能：获取一个验证码类的实例
* 
* @return
*/
public static VerifyCode Instance() {
if (instance == null) {
instance = new VerifyCode();
}
return instance;
}


private VerifyCode() {
BufferedImage image = new BufferedImage(WIDTH, HEIGHT,
BufferedImage.TYPE_INT_RGB);
int randomNum = new Random().nextInt(3);
if (randomNum == 0) {
initNumVerificationCode(image);
} else if (randomNum == 1) {
initLetterAndNumVerificationCode(image);
} else {
initChinesePlusNumVerificationCode(image);
}
}


/**
* 功能：设置第一种验证码的属性
*/
private void initNumVerificationCode(BufferedImage image) {


Random random = new Random(); // 生成随机类
Graphics g = initImage(image, random);
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);
}
this.setStr(sRand);/* 赋值验证码 */
// 图象生效
g.dispose();
this.setImage(drawImage(image));
}


/**
* 功能：设置第二种验证码属性
*/
private void initLetterAndNumVerificationCode(BufferedImage image) {


Random random = new Random(); // 生成随机类
Graphics g = initImage(image, random);
String[] letter = { "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 sRand = "";
for (int i = 0; i < 4; i++) {
String tempRand = "";
if (random.nextBoolean()) {
tempRand = String.valueOf(random.nextInt(10));
} else {
tempRand = letter[random.nextInt(25)];
if (random.nextBoolean()) {// 随机将该字母变成小写
tempRand = tempRand.toLowerCase();
}
}
sRand += tempRand;
g.setColor(new Color(20 + random.nextInt(10), 20 + random
.nextInt(110), 20 + random.nextInt(110)));
g.drawString(tempRand, 13 * i + 6, 16);
}
this.setStr(sRand);/* 赋值验证码 */
g.dispose(); // 图象生效
this.setImage(drawImage(image));
}


/**
* 功能：设置第三种验证码属性 即：肆+？=24
*/
private void initChinesePlusNumVerificationCode(BufferedImage image) {
String[] cn = { "壹", "贰", "叁", "肆", "伍", "陆", "柒", "捌", "玖", "拾" };
Random random = new Random(); // 生成随机类
Graphics g = initImage(image, random);
int x = random.nextInt(10) + 1;
int y = random.nextInt(30);
this.setStr(String.valueOf(y));
g.setFont(new Font("楷体", Font.PLAIN, 14));// 设定字体
g.setColor(new Color(20 + random.nextInt(10), 20 + random.nextInt(110),
20 + random.nextInt(110)));
g.drawString(cn[x - 1], 1 * 1 + 6, 16);
g.drawString("+", 22, 16);
g.drawString("？", 35, 16);
g.drawString("=", 48, 16);
g.drawString(String.valueOf(x + y), 61, 16);
g.dispose(); // 图象生效
this.setImage(drawImage(image));


}


private Graphics initImage(BufferedImage image, Random random) {
Graphics g = image.getGraphics(); // 获取图形上下文
g.setColor(getRandColor(200, 250));// 设定背景色
g.fillRect(0, 0, WIDTH, HEIGHT);
g.setFont(new Font("Times New Roman", Font.PLAIN, 14));// 设定字体
g.setColor(getRandColor(160, 200)); // 随机产生165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 < 165; 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);
}
return g;
}


private ByteArrayInputStream drawImage(BufferedImage image) {
ByteArrayInputStream input = null;
ByteArrayOutputStream output = new ByteArrayOutputStream();
try {
ImageOutputStream imageOut = ImageIO
.createImageOutputStream(output);
ImageIO.write(image, "JPEG", imageOut);
imageOut.close();
input = new ByteArrayInputStream(output.toByteArray());
} catch (Exception e) {
System.out.println("验证码图片产生出现错误：" + e.toString());
}
return input;
}


/**
* 功能：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);
}


/**
* 功能：获取验证码的字符串值
* 
* @return
*/
public String getVerificationCodeValue() {
return this.getStr();
}


/**
* 功能：取得验证码图片
* 
* @return
*/
public ByteArrayInputStream getImage() {
return this.image;
}


public String getStr() {
return code;
}


public void setStr(String str) {
this.code = str;
}


public void setImage(ByteArrayInputStream image) {
this.image = image;
}
}