版权声明:本文为博主原创文章,未经博主允许不得转载。 https://blog.csdn.net/caojidasabi/article/details/78045565
package response_test;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import cn.dsna.util.images.ValidateCode;
public class Response_demo4 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//test(response);
//告诉客户端不要使用缓存
response.setHeader("pragma", "no-cache");
response.setHeader("cache-control", "no-cache");
response.setIntHeader("expores", 0);
//使用ValidateCode.jar
ValidateCode vc=new ValidateCode(110, 25, 4, 9);
String code=vc.getCode();
System.out.println(code);//测试
vc.write(response.getOutputStream());
}
private void test(HttpServletResponse response) throws IOException {
//告诉客户端不要使用缓存
response.setHeader("pragma", "no-cache");
response.setHeader("cache-control", "no-cache");
response.setIntHeader("expores", 0);
int width=110;
int height=25;
//在内存中创建一个图像对象
BufferedImage img =new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
//创建一个画笔
Graphics g=img.getGraphics();
//给图片添加背景色
g.setColor(Color.PINK);
g.fillRect(1, 1, width-2, height-2);
//设置文本样式
g.setColor(Color.BLUE);
g.setFont(new Font("宋体", Font.BOLD|Font.ITALIC, 15));
//给图片添加文本
Random rand=new Random();
int position=20;
for(int i=0;i<4;i++){
g.drawString(rand.nextInt(10)+"", position, 20);
position+=20;
}
for (int i = 0; i < 6; i++) {
g.drawLine(rand.nextInt(width), rand.nextInt(height), rand.nextInt(width), rand.nextInt(height));
}
ImageIO.write(img, "jpg", response.getOutputStream());
}
public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
}
}
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>登陆界面</title>
</head>
<script>
function changeCode(){
var img=document.getElementsByTagName("img")[0];
img.src="/response_test/demo4?time="+new Date().getTime();
}
</script>
<body>
<form action="#" method="post">
用户名: <input type="text" name="" id="" style="width: 139px; "><br>
密码: <input type="text" name="" id=""> <br>
验证码:<input type="text" name=""><img src="/response_test/demo4" alt="" onclick="changeCode()"><br>
<input type="submit" name="" id="">
</form>
</body>
</html>