1.鍓嶅彴jsp
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
聽聽<head>
聽聽 聽<base href="<%=basePath%>" target="_blank" rel="external nofollow" >
聽聽 聽<title>绠＄悊鍛樼櫥闄?lt;/title>
<script type="text/javascript" language="javascript">
聽聽function change(){
var o = document.getElementById("random");
var timenow = new Date().getTime();
o.src = "<%=path%>/server/ImageValidate?d=" + timenow;
聽聽}
</script>
聽聽</head>
聽聽<body>
聽聽 聽 聽 聽<img width="80px" 聽height="30px" id="random" src="<%=path %>/server/ImageValidate"/>
聽聽 聽 聽 聽<input type="button" value="鎹竴寮犲浘鐗? id="label" 慰nclick="change()"></input>
聽聽</body>
</html>
聽
2.鍚庡彴鐢熷瓨闅忔満鐮佺殑servlet
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.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
聽
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
聽
@SuppressWarnings("serial")
public class ImageValidate extends HttpServlet {
public ImageValidate() {
super();
}
public void destroy() {
super.destroy(); // Just puts "destroy" string in log
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("GBK");
response.setCharacterEncoding("GBK");
response.setContentType("image/jpeg");
聽聽 聽 聽 聽response.addHeader("pragma","NO-cache");
聽聽 聽 聽 聽response.addHeader("Cache-Control","no-cache");
聽聽 聽 聽 聽response.addDateHeader("Expries",0);
聽聽 聽 聽 聽int width=80, height=30;
response.setContentType("text/html; charset=GBK");
String chose="0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
char temp;//淇濆瓨闅忔満鐢熸垚鐨刢hose鍏冪礌
Random rand=new Random();
聽 聽 聽 聽BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
聽 聽 聽 聽Graphics g = image.getGraphics();
聽 聽 聽 聽//浠ヤ笅濉厖鑳屾櫙棰滆壊
聽 聽 聽 聽g.setColor(Color.YELLOW);
聽 聽 聽 聽g.fillRect(0, 0, width, height);
聽 聽 聽 //鐢昏竟妗?
聽 聽 聽 聽g.setColor(Color.BLACK);
聽 聽 聽 聽Font font;
聽 聽 聽 聽g.drawRect(0,0,width-1,height-1);
聽 聽 聽 聽StringBuffer sRand = new StringBuffer();
// 闅忔満浜х敓30鏉″共鎵扮嚎锛屼嬌鍥捐薄涓殑璁よ瘉鐮佷笉鏄撹鍏跺畠绋嬪簭鎺㈡祴鍒? for (int i = 0; i < 30; i++) {
聽 聽 聽 聽 int x = rand.nextInt(width);
聽 聽 聽 聽 int y = rand.nextInt(height);
聽 聽 聽 聽 int xl = rand.nextInt(12);
聽 聽 聽 聽 int yl = rand.nextInt(12);
聽 聽 聽 聽 g.drawLine(x,y,x+xl,y+yl);
}
聽 聽 聽 聽for(int i=0;i<4;i++){
temp=chose.charAt(rand.nextInt(chose.length()));
sRand.append(temp);
font=new Font("Arial",Font.PLAIN,15 + rand.nextInt(10));//瀛椾綋
聽 聽 聽 聽g.setFont(font);
g.setColor(new Color(rand.nextInt(255),0,rand.nextInt(255)));//楠岃瘉鐮佺殑棰滆壊
g.drawString(String.valueOf(temp),15*i+5,20+rand.nextInt(10));//浣嶇疆
}
request.getSession().setAttribute("randomNumber",sRand.toString());//淇濆瓨鐢熸垚鐨勯獙璇佺爜鍊?
聽 聽 聽 //璁劇疆瀛椾綋棰滆壊
聽 聽 聽 聽g.dispose();
聽 聽 聽 聽ServletOutputStream outStream = response.getOutputStream();
聽 聽 聽 聽JPEGImageEncoder encoder =JPEGCodec.createJPEGEncoder(outStream);
聽 聽 聽 聽encoder.encode(image);
聽 聽 聽 聽outStream.close();
}
public void init() throws ServletException {
}
}
3.xml閰嶇疆鏂囦歡 <servlet> 聽聽 聽<servlet-name>ImageValidate</servlet-name> 聽聽 聽<servlet-class>user.ImageValidate</servlet-class> 聽聽</servlet> 聽聽<servlet-mapping> 聽聽 聽<servlet-name>ImageValidate</servlet-name> 聽聽 聽<url-pattern>/server/ImageValidate</url-pattern> 聽聽</servlet-mapping>
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