package utils;

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.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import org.apache.struts2.ServletActionContext;

public class CodeUtil{

private Color getRandColor(int fc, int bc) {

//给定范围获得随机颜色

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);

}

public void createCode(HttpServletRequest request,HttpServletResponse response){

//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 = 75, height = 32;

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.BOLD, 18));//18是设置的字体大小

//画边框

g.setColor(new Color(0, 0, 0));

g.drawRect(0, 0, width - 1, height -1);// 细线围成的边框范围

// 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 = null;

//随机生成数字或者字母

if (random.nextInt(10) > 5) {

rand = String.valueOf((char)(random.nextInt(10) + 48));

}else {

rand = String.valueOf((char)(random.nextInt(26) + 65));

}

sRand += rand;

// 将认证码显示到图象中

g.setColor(new Color(random.nextInt(80), random.nextInt(80), random.nextInt(80)));

//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, 15 * i + 10, 16);

}

// 将认证码存入SESSION

request.getSession().setAttribute("rand", sRand);

// 图象生效

g.dispose();

// 输出图象到页

try {

//output:an OutputStream to be written to

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

} catch (IOException e) {

e.printStackTrace();

}

}

}