package com.bookshop.util;

import java.awt.BasicStroke;

import java.awt.Color;

import java.awt.Font;

import java.awt.Graphics;

import java.awt.Graphics2D;

import java.awt.image.BufferedImage;

import java.io.IOException;

import java.util.Random;

import javax.imageio.ImageIO;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class ValidateCode {

// 输出一张随机验证码图片

public static final int WIDTH = 160;

public static final int HEIGHT = 50;

//生成验证码

public static HttpServletResponse generateValidateCode(HttpServletRequest request,

HttpServletResponse response) throws IOException

{

BufferedImage image = new BufferedImage(WIDTH, HEIGHT,BufferedImage.TYPE_INT_RGB);

Graphics g = image.getGraphics();

// 1.設置背景色

setBackGround(g);

// 2.設置邊框

setBorder(g);

// 3.画干扰线

drawRandomLine(g);

// 4.写随机数

String random = drawRandomNum((Graphics2D) g);

// 写给客户机的同时也给服务器一份,将验证码存到session中

request.getSession().setAttribute("imagecheckcode", random);

// 5.把图形写给浏览器

// 通知浏览器以图形的方式打开

response.setContentType("image/jpeg");

// 发头控制浏览器不要缓存

response.setDateHeader("expries", -1);

response.setHeader("Cache-Control", "no-cache");

response.setHeader("Pragma", "no-cache");

//将图像输出到Servlet输出流中。

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

return response;

}

private static String drawRandomNum(Graphics2D g) {

// TODO Auto-generated method stub

g.setColor(new Color(123 ,104 ,238));

g.setFont(new Font("宋体", Font.BOLD, 40));

// 所有的汉字都在Unicode【\u4e00--\u9fa5】区间,所有的中文都是以Unicode码存进去的。所以char c =

// '\u4e00',相当于char c='一'

String base = "\u0051\u0057\u0045\u0052\u0054\u0059\u0055\u0049\u004f\u0050\u0041\u0053\u0044\u0046\u0047\u0048\u004a\u004b\u004c\u005a\u0058\u0043\u0056\u0042\u004e\u004d"

+ "\u0071\u0077\u0065\u0072\u0074\u0079\u0075\u0069\u006f\u0070\u0061\u0073\u0064\u0066\u0067\u0068\u006a\u006b\u006c\u007a\u0078\u0063\u0076\u0062\u006e\u006d"

+ "\u0031\u0032\u0033\u0034\u0035\u0036\u0037\u0038\u0039\u0030";

StringBuffer sb = new StringBuffer();

int x = 14;

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

int degree = new Random().nextInt() % 30;// 求30余数，返回负30到正30的随机数。

String ch = base.charAt(new Random().nextInt(base.length())) + "";// 加完“

sb.append(ch); // ”之后就有char类型转换为string类型了。

g.rotate(degree * Math.PI / 180, x, 35);// 设置旋转的角度，弧度制的

g.drawString(ch, x, 35);

g.rotate(-degree * Math.PI / 180, x, 35);// 把旋转后的字再旋转回去了，要不然一直循环，角度会一直跟着变大。注意字会旋转出验证码所在的框。

x += 40;

}

return sb.toString();

}

private static void drawRandomNum2(Graphics2D g) {

// TODO Auto-generated method stub

g.setColor(Color.white);

g.setFont(new Font("宋体", Font.BOLD, 20));

// 所有的汉字都在Unicode【\u4e00--\u9fa5】区间,所有的中文都是以Unicode码存进去的。所以char c =

// '\u4e00',相当于char c='一'

String base = "看不清，换一张";

g.drawString(base, 14, 30);

}

private static void drawRandomLine(Graphics g) {

// TODO Auto-generated method stub

Color[] colors = {new Color(126 ,192 ,238),new Color(255, 185, 15),new Color(255, 127, 80),new Color(0, 178, 238),new Color(144 ,238 ,144)};

Graphics2D g2 = (Graphics2D) g;

g2.setStroke(new BasicStroke(2.0f));

g2.setFont(new Font("宋体", Font.BOLD, 600));

int width = WIDTH +10;

int height = HEIGHT+10;

for (int i = 0; i < 13; i++) {

g2.setColor(colors[new Random().nextInt(2)]);

int x1 = new Random().nextInt(width);

int y1 = new Random().nextInt(height);

int x2 = new Random().nextInt(width);

int y2 = new Random().nextInt(height);

g2.drawLine(x1, y1, x2, y2);

}

}

private static void setBorder(Graphics g) {

// TODO Auto-generated method stub

g.setColor(new Color(255, 255, 255));

g.drawRect(0, 0, WIDTH, HEIGHT);

}

private static void setBackGround(Graphics g) {

// TODO Auto-generated method stub

g.setColor(new Color(255, 255, 255));

g.fillRect(1, 1, WIDTH - 2, HEIGHT - 2);

}

}