hwly
package cn.itcast.web.servlet;
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.BufferedReader;
import java.io.IOException;
import java.util.Enumeration;
import java.util.Map;
import java.util.Random;
import java.util.Set;
@WebServlet("/checkCodeServlet")
public class CheckCodeServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
int width=100;
int height=50;
BufferedImage image=new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);//创建一个图片对象,在内存中显示
Graphics g=image.getGraphics();//画笔对象
g.setColor(Color.PINK);//设置画笔颜色为粉红
g.fillRect(0,0,width,height);
g.setColor(Color.BLUE); //边框
g.drawRect(0,0,width,height);
//写验证码
Random ran = new Random();
for (int i=1;i<=4;i++) {
//生产随机下标
String str = "ABCDEFGHIJKLMNOQPRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
int index = ran.nextInt(str.length());
char ch = str.charAt(index);
g.drawString(ch+"", width/5*i, height/2);
}
//画干扰线
g.setColor(Color.GREEN);
//随机生产坐标
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);
}
ImageIO.write(image,"jpg",response.getOutputStream());//将页面输出展示
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request,response);
}
}
利用js完成单击图片实现验证码切换
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script>
//获取图片对象
var img=document.getElementById("checkCode");
//绑定单击事件
img.onclick=function () {
var date=new Date().getTime();
//利用时间戳使参数永不重复
img.src="/tomcatt/checkCodeServlet?"+date;///tomcatt/checkCodeServlet如果这样写点击图片不会完成切换,因为路径未改变
//?:http get请求携带参数
}
</script>
</head>
<body>
<img id="checkCode" src="/tomcatt/checkCodeServlet"/>
<a id="change" href="">kbqhyz</a>
</body>
</html>`