package cn.itcast.web;


import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
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;


public class CheckcodeServlet extends HttpServlet {
private static final long serialVersionUID = 1L;


protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//  创建画布
int width = 120;
int height = 40;
BufferedImage bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
//  获得画笔
Graphics g = bufferedImage.getGraphics();
//  填充背景颜色
g.setColor(Color.white);
g.fillRect(0, 0, width, height);
//  绘制边框
g.setColor(Color.red);
g.drawRect(0, 0, width - 1, height - 1);
//  生成随机字符
//  准备数据
String data = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890";
//  准备随机对象
Random r = new Random();
//  声明一个变量 保存验证码
String code = "";
//  书写4个随机字符
for (int i = 0; i < 4; i++) {
//  设置字体
g.setFont(new Font("宋体", Font.BOLD, 28));
//  设置随机颜色
g.setColor(new Color(r.nextInt(255), r.nextInt(255), r.nextInt(255)));


String str = data.charAt(r.nextInt(data.length())) + "";
g.drawString(str, 10 + i * 28, 30);


//  将新的字符 保存到验证码中
code = code + str;
}
//  绘制干扰线
for (int i = 0; i < 6; i++) {
//  设置随机颜色
g.setColor(new Color(r.nextInt(255), r.nextInt(255), r.nextInt(255)));


g.drawLine(r.nextInt(width), r.nextInt(height), r.nextInt(width), r.nextInt(height));
}


//  将验证码 打印到控制台
System.out.println(code);


//  将验证码放到session中
request.getSession().setAttribute("code_session", code);


//  将画布显示在浏览器中
ImageIO.write(bufferedImage, "jpg", response.getOutputStream());
}


protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}


}