标签：charset extends graphic 服务 res 边框 rand cli 图片
<!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); } }
标签：charset extends graphic 服务 res 边框 rand cli 图片
原文地址：https://www.cnblogs.com/yyanghang/p/12236027.html
