javaweb校验码及干扰线的生成

1.

在与上一个java类相同路径下新建一个新的java类命名为CaptcheController

继承于HttpServlet ，重写service，设置映射关系为/captche

package cn.edu.mju.project13.controller;

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("/Captche")
public class CaptcheController extends HttpServlet {
    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        ServletOutputStream sos =  resp.getOutputStream();
        ImageIO.write(generatepic(300,280),"JPEG",sos);
        sos.flush();
        sos.close();
    }

定义并且编辑BufferedImage generatePic函数

 private BufferedImage generatepic(int width,int height){
        Random random = new Random();
        BufferedImage image = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
        Graphics g =image.getGraphics();
        g.setFont(new Font("宋体",Font.BOLD,20));
        g.setColor(Color.WHITE);
        g.fillRect(0,0,width,height);
        g.setColor(Color.BLACK);
         g.drawString("1234",10,20);
        for(int j=0,n=random.nextInt(100);j<n;j++){   //设置随机点
            g.setColor(Color.RED);
            g.fillRect(random.nextInt(width),random.nextInt(height),1,1);
        }
        for (int i=0;i<5;i++){ //每条线随机颜色
            g.setColor(new Color(random.nextInt(255),random.nextInt(255), random.nextInt(255)));
            int x1=random.nextInt(90);
            int y1=random.nextInt(30);
            int x2=random.nextInt(90);
            int y2=random.nextInt(30);
            g.drawLine(x1,y1,x2,y2);
        }
        g.dispose();
        return image;
    }

代码编写完成，进入http://localhost:9091/Project13/Captche，查看网页效果