图片验证码生成代码

package cn.itcast.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.创建一对象，在内存中图片(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 g = image.getGraphics();//画笔对象
    g.setColor(Color.PINK);//设置画笔颜色
    g.fillRect(0,0,width,height);

    //2.2画边框
    g.setColor(Color.BLUE);
    g.drawRect(0,0,width - 1,height - 1);

    String str = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghigklmnopqrstuvwxyz0123456789";
    //生成随机角标
    Random ran = new Random();

    for (int i = 1; i <= 4; i++) {
        int index = ran.nextInt(str.length());
        //获取字符
        char ch = str.charAt(index);//随机字符
        //2.3写验证码
        g.drawString(ch+"",width/5*i,height/2);
    }


    //2.4画干扰线
    g.setColor(Color.GREEN);

    //随机生成坐标点

    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);
}

}