/**
*
*/
package com.hxzk.util;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
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;
/**
* 随机生成验证图片
*
* @author 程文博 270885718@qq.com <br/>
* 2016-7-1 下午13:05:08
*
*/
public class RandCodeImageServlet extends HttpServlet {
private static final long serialVersionUID = -1257947018545327308L;
private static final String SESSION_KEY_OF_RAND_CODE = "randCode"; // todo 要统一常量
/**
*
*/
private static final int count = 200;
/**
* 定义图形大小
*/
private static final int width = 105;
/**
* 定义图形大小
*/
private static final int height = 35;
// private Font mFont = new Font("Arial Black", Font.PLAIN, 15); //设置字体
/**
* 干扰线的长度=1.414*lineWidth
*/
private static final int lineWidth = 2;
@Override
public void doGet(final HttpServletRequest request, final 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);
// response.setContentType("image/png");
// 在内存中创建图象
final BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
// 获取图形上下文
final Graphics2D graphics = (Graphics2D) image.getGraphics();
// 设定背景颜色
graphics.setColor(Color.WHITE); // ---1
graphics.fillRect(0, 0, width, height);
// 设定边框颜色
// graphics.setColor(getRandColor(100, 200)); // ---2
graphics.drawRect(0, 0, width - 1, height - 1);
final Random random = new Random();
// 随机产生干扰线，使图象中的认证码不易被其它程序探测到
for (int i = 0; i < count; i++) {
graphics.setColor(getRandColor(150, 200)); // ---3
final int x = random.nextInt(width - lineWidth - 1) + 1; // 保证画在边框之内
final int y = random.nextInt(height - lineWidth - 1) + 1;
final int xl = random.nextInt(lineWidth);
final int yl = random.nextInt(lineWidth);
graphics.drawLine(x, y, x + xl, y + yl);
}
// 取随机产生的认证码(4位数字)
final String resultCode = exctractRandCode();
for (int i = 0; i < resultCode.length(); i++) {
// 将认证码显示到图象中,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
// graphics.setColor(new Color(20 + random.nextInt(130), 20 + random
// .nextInt(130), 20 + random.nextInt(130)));
// 设置字体颜色
//graphics.setColor(Color.BLACK);
graphics.setColor(getRandColor(0, 200));
// 设置字体样式
// graphics.setFont(new Font("Arial Black", Font.ITALIC, 18));
graphics.setFont(new Font("Times New Roman", Font.BOLD, 24));
// 设置字符，字符间距，上边距
graphics.drawString(String.valueOf(resultCode.charAt(i)), (23 * i) + 8, 26);
}
// 将认证码存入SESSION
request.getSession().setAttribute(SESSION_KEY_OF_RAND_CODE, resultCode);
// 图象生效
graphics.dispose();
// 输出图象到页面
ImageIO.write(image, "JPEG", response.getOutputStream());
}
@Override
public void doPost(final HttpServletRequest request, final HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
/**
* @return 随机码
*/
private String exctractRandCode() {
final String randCodeType = "5"; //验证码随机字符标本
int randCodeLength = 4; //验证码长度
if (randCodeType == null) {
return RandCodeImageEnum.NUMBER_CHAR.generateStr(randCodeLength);
} else {
switch (randCodeType.charAt(0)) {
case '1':
return RandCodeImageEnum.NUMBER_CHAR.generateStr(randCodeLength);
case '2':
return RandCodeImageEnum.LOWER_CHAR.generateStr(randCodeLength);
case '3':
return RandCodeImageEnum.UPPER_CHAR.generateStr(randCodeLength);
case '4':
return RandCodeImageEnum.LETTER_CHAR.generateStr(randCodeLength);
case '5':
return RandCodeImageEnum.ALL_CHAR.generateStr(randCodeLength);
default:
return RandCodeImageEnum.NUMBER_CHAR.generateStr(randCodeLength);
}
}
}
/**
* 描述：
*
* @param fc 描述：
* @param bc 描述：
*
* @return 描述：
*/
private Color getRandColor(int fc, int bc) { // 取得给定范围随机颜色
final Random random = new Random();
if (fc > 255) {
fc = 255;
}
if (bc > 255) {
bc = 255;
}
final int r = fc + random.nextInt(bc - fc);
final int g = fc + random.nextInt(bc - fc);
final int b = fc + random.nextInt(bc - fc);
return new Color(r, g, b);
}
}
/**
* 验证码辅助类
*
* @author 程文博 270885718@qq.com <br/>
* 2016-7-1 下午13:05:08
*
*/
enum RandCodeImageEnum {
/**
* 混合字符串
*/
ALL_CHAR("0123456789abcdefghijkmnpqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"), // 去除小写的l和o这个两个不容易区分的字符；
/**
* 字符
*/
LETTER_CHAR("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"),
/**
* 小写字母
*/
LOWER_CHAR("abcdefghijklmnopqrstuvwxyz"),
/**
* 数字
*/
NUMBER_CHAR("0123456789"),
/**
* 大写字符
*/
UPPER_CHAR("ABCDEFGHIJKLMNOPQRSTUVWXYZ");
/**
* 待生成的字符串
*/
private String charStr;
/**
* @param charStr
*/
private RandCodeImageEnum(final String charStr) {
this.charStr = charStr;
}
/**
* 生产随机验证码
*
* @param codeLength 验证码的长度
* @return 验证码
*/
public String generateStr(final int codeLength) {
final StringBuffer sb = new StringBuffer();
final Random random = new Random();
final String sourseStr = getCharStr();
for (int i = 0; i < codeLength; i++) {
sb.append(sourseStr.charAt(random.nextInt(sourseStr.length())));
}
return sb.toString();
}
/**
* @return the {@link #charStr}
*/
public String getCharStr() {
return charStr;
}
}
