package com.free.util;

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.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class CodeMakerServlet extends HttpServlet
{
      /**
     * 
     */
    private static final long serialVersionUID = 1L;
    
    //生成随机类
    Random random = new Random();
    
    //验证码字体
    private Font[] codeFont =
    {
        new Font("Times New Roman", Font.PLAIN,18), 
        new Font("Times New Roman", Font.PLAIN, 18),
        new Font("Times New Roman", Font.PLAIN,18),
        new Font("Times New Roman", Font.PLAIN, 18)
    };
    //验证码数字颜色
    private Color[] color =
    {
       Color.BLACK, Color.RED, Color.DARK_GRAY, Color.BLUE
    };

    String codeNumbers = "";

    int width = 60, height = 20;

    // 处理 HTTP get 请求
    public void doGet(HttpServletRequest request, HttpServletResponse response)
                      throws ServletException, IOException
    {
        System.out.println("生成验证码");
        // 清空缓冲区
        response.reset();

        // 注意这里的MIME类型
        response.setContentType("image/png");

        // 设置页面不缓存
        response.setHeader("Pragma", "No-cache");
        response.setHeader("Cache-Control", "no-cache");
        response.setDateHeader("Expires", 0);

        // 创建一个图像,验证码显示的图片大小
        BufferedImage image = new BufferedImage(width, height,BufferedImage.TYPE_INT_RGB);

        // 获取图形上下文
        Graphics g = image.getGraphics();
        
        // 设置背景
        g.setColor(getRandColor(200,250));
        g.fillRect(0, 0, width, height);

        for (int i = 0; i < 4; i++)
        {
            drawCode(g, i);
        }
        //添加干扰线
        drawNoise(g, 12);

        // 绘制边框
        //g.setColor(Color.gray);
        //g.drawRect(0, 0, width - 1, height - 1);

        // 将验证码内容保存进session中，用于验证用户输入是否正确时使用
        HttpSession session = request.getSession(true);
        session.removeAttribute("rand");
        session.setAttribute("rand", codeNumbers);
        // 重设字符串
        codeNumbers = "";
        // 利用ImageIO类的write方法对图像进行编码
        ServletOutputStream sos = response.getOutputStream();
        ImageIO.write(image, "PNG", sos);
        sos.close();
    }

    // 绘制验证码
    public void drawCode(Graphics graphics, int i)
    {
        String number = String.valueOf(random.nextInt(10));
        graphics.setFont(codeFont[i]);
        graphics.setColor(color[i]);
        //绘制验证码到图片X、Y
        graphics.drawString(number, 6 + i * 13,16);

        codeNumbers += number;
    }

    // 绘制干扰线
    public void drawNoise(Graphics graphics, int lineNumber)
    {
        graphics.setColor(getRandColor(160,200));
        for (int i = 0; i < lineNumber; i++)
        {
            int pointX1 = 1 + (int)(Math.random() * width);
            int pointY1 = 1 + (int)(Math.random() * height);
            int pointX2 = 1 + (int)(Math.random() * width);
            int pointY2 = 1 + (int)(Math.random() * height);
            graphics.drawLine(pointX1, poi