<!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: 2024-11-02 23:42:25