验证码的书写

package com.hopetesting.web.servlet;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
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;

/**
 * @author newcityman
 * @date 2019/9/1 - 20:42
 */
@WebServlet("/checkCode")
public class CheckCodeServlet extends HttpServlet {
 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// 1、创建一个对象，在内存中存放图片（验证码图片对象）
 int width=100;
 int height=50;
 BufferedImage image = new BufferedImage(width,height, BufferedImage.TYPE_INT_RGB);
// 2、美化图片
// 2.1、填充背景色
 Graphics g = image.getGraphics();
 g.setColor(Color.PINK);
 g.fillRect(0,0,width,height);

// 2.2、画矩形边框
 g.setColor(Color.blue);
 g.drawRect(0,0,width-1,height-1);

// 2.3、随机生成角标
 String str="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghighjklmnopqrstuvwxyz0123456789";
 Random ran = new Random();

// 获取字符
 g.setColor(Color.RED);
 for (int i = 1; i <=4 ; i++) {
 int index = ran.nextInt(str.length());
 char c = str.charAt(index);
 g.drawString(c+"",width/5*i,height/2);
 }
// 2.4 设置干扰线
 g.setColor(Color.BLACK);

 for(int i=0;i<10;i++){
 int x1 = ran.nextInt(width);
 int x2 = ran.nextInt(width);

 int y1 = ran.nextInt(height);
 int y2 = ran.nextInt(height);
 g.drawLine(x1,y1,x2,y2);
 }


// 3、将图片输送到页面显示
 ImageIO.write(image,"jpg",response.getOutputStream());


 }

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