简易验证码

package com.itcsl.web.servlet;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;

@WebServlet("/CheckCodeServlet")
public class CheckCodeServlet extends HttpServlet {
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		int width=100;
		int height=50;
		//1.创建一个对象，在内存中画图(验证码图片对象)
		BufferedImage image = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
		//2.美化图片
		//2.1填充背景色
		Graphics graphics = image.getGraphics();//画笔对象
		graphics.setColor(Color.pink);//设置画笔颜色
		graphics.fillRect(0,0,width,height);
		//2.2画边框
		graphics.setColor(Color.BLUE);
		graphics.drawRect(0,0,width-1,height-1);

		String str="QWERTYUIOPASDFGHJKLZXCVBNMqwertyuiopasdfghjklzxcvbnm1234567890";
		//生成随机角标
		Random random = new Random();
		for (int  i=1;i<=4;i++){
			int index = random.nextInt(str.length());
			//获取字符
			char ch = str.charAt(index);
			//2.3写验证码
			graphics.drawString(ch+"",width/5*i,height/2);
		}
		//2.4画干扰线
		graphics.setColor(Color.GREEN);
		//随机生成做坐标点
		for (int i = 1; i <=10 ; i++) {
			int x1 = random.nextInt(width);
			int x2 = random.nextInt(width);

			int y1 = random.nextInt(height);
			int y2 = random.nextInt(height);
			graphics.drawLine(x1,x2,y1,y2);
		}
		//3.将图片输出到页面展示
		ImageIO.write(image,"jpg",response.getOutputStream());
	}
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		this.doPost(request,response);
	}
}