<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>验证码点击切换</title>
<script>
/*
分析：
点击超链接或者图片，需要换一张
1.给超链接和图片绑定单击事件
2.重新设置图片的src属性值
*/
window.onload=function () {//加载完毕后
var img = document.getElementById("checkCode");
img.onclick = function () {//绑定单击事件
//加时间戳 欺骗服务器
var date = new Date().getTime();
img.src="/order7_Request_Response_war_exploded/checkCodeServlet?"+date;
}
var a = document.getElementById("change");
a.onclick = function () {
//加时间戳 欺骗服务器
var date = new Date().getTime();
img.src="/order7_Request_Response_war_exploded/checkCodeServlet?"+date;
}
}
</script>
</head>
<body>
<img id="checkCode" src="/order7_Request_Response_war_exploded/checkCodeServlet">
<a id="change" href="">看不清？换一张</a>
</body>
</html>
package web.response;
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;
/**
验证码 案例
*/
@WebServlet( "/checkCodeServlet")
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
int width = 100;
int heigth = 50;
BufferedImage image = new BufferedImage(width,heigth,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,heigth);//填充矩形
//2.2画边框
graphics.setColor(Color.BLUE);
graphics.drawRect(0,0,width-1,heigth-1);//因为画笔有1px 所以要减一
//2.3填写验证码
String str = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
Random random = new Random();
for (int i = 1; i <=4 ; i++) {
int index = random.nextInt(str.length());
graphics.drawString(str.charAt(index)+"",width/5*i,heigth/2);
}
//2.4画干扰线
graphics.setColor(Color.green);
for (int i = 0; i <10 ; i++) {
int x1 = random.nextInt(width);
int x2 = random.nextInt(width);
int y1 = random.nextInt(heigth);
int y2 = random.nextInt(heigth);
graphics.drawLine(x1,y1,x2,y2);
}
//3.将图片输出至页面展示
ImageIO.write(image,"jpg",response.getOutputStream());
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request,response);
}
}
原文地址：https://www.cnblogs.com/yyanghang/p/12236027.html
时间： 2024-08-29 05:02:23