java驗證碼學習一

標籤：java驗證碼學習一

package com.sys.web.sesoion;import java.io.IOException;import java.io.PrintWriter;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import java.awt.Graphics;import java.awt.image.BufferedImage;import java.util.Random;import javax.imageio.ImageIO;import javax.servlet.http.HttpSession;public class CheckCodeServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { BufferedImage image = new BufferedImage(50,25,BufferedImage.TYPE_INT_RGB); Graphics g = image.getGraphics(); g.drawString(Token.getNum(),15,15); ImageIO.write(image,"JPG",response.getOutputStream()); response.setHeader("expires","-1"); response.setHeader("cache-control","no-cache"); //沒有緩成 response.setHeader("pragma","no-cache"); }}//用於產生隨機數class Token{ public static String getNum(){ Random r = new Random(); int num = r.nextInt(10000); return num + ""; }}

java驗證碼學習一