package test.captcha;

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;

/**

* 生成验证码

* @author striner

*

*/

public class Captcha extends HttpServlet {

private static final long serialVersionUID = 1L;

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

int width = 110;

int height = 25;

//在内存中创建一个图像对象

BufferedImage img = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); //RGB:三原色

//创建一个画笔

Graphics g = img.getGraphics();

//给图片添加背景色

g.setColor(Color.PINK); //设置颜色

g.fillRect(1, 1, width-2, height-2); //设置边框显示坐标 g.fillRect(上, 右, 下, 左)

//给边框一个色

//g.setColor(Color.GRAY);

g.setColor(Color.CYAN); //CYAN: 浅蓝色

g.fillRect(0, 0, width-1, height-1);

//设置文本样式

g.setColor(Color.BLUE);

g.setFont(new Font("宋体", Font.BOLD|Font.ITALIC, 15)); //Font.BOLD:加粗 Font.ITALIC:斜体

//给图片添加文本

Random rand = new Random();

int position = 20; //第一个数字的横坐标

for (int i = 0; i < 4; i++) { //随机产生四个数字

g.drawString(rand.nextInt(10)+"", position, 20); //drawString(String, int, int) 给图片填充文本

position += 20; //每两个数之间横间距为20px

}

//添加9条干扰线

for(int i = 0; i < 9; i++) {

g.drawLine(rand.nextInt(width), rand.nextInt(height), rand.nextInt(width), rand.nextInt(height));

}

//将图片对象以流的方式输出到客户端

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

}

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

doGet(request, response);

}

}