不使用Java插件来生成Java验证码
代码如：
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 javax.servlet.http.HttpSession;import org.mortbay.log.Log; @SuppressWarnings("serial")public class RegisterCaptcha1 extends HttpServlet { public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //设置页面不缓存 response.setHeader("Pragma","No-cache"); response.setHeader("Cache-Control","no-cache"); response.setDateHeader("Expires", 0); // 设置图片的长宽 /* int width = Integer.parseInt(request.getParameter("width")); int height = Integer.parseInt(request.getParameter("height"));*/ int width=120, height=30; // 备选字符集 // String[] set = {"a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","y","z","0","1","2","3","4","5","6","7","8","9"}; String[] set = {"0","1","2","3","4","5","6","7","8","9"}; // 备选字体 String[] fontTypes = {"\u5b8b\u4f53","\u65b0\u5b8b\u4f53","\u9ed1\u4f53","\u6977\u4f53","\u96b6\u4e66"}; // 创建内存图像 BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); // 获取图形上下文 Graphics graphics = image.getGraphics(); // 设定图像背景色(设置为白色) graphics.setColor(Color.WHITE); graphics.fillRect(0, 0, width, height); //创建随机类的实例 Random random = new Random(); //在图片背景上增加噪点 graphics.setColor(getRandColor(random,160,200)); graphics.setFont(new Font("Times New Roman",Font.PLAIN,14)); for (int i=0;i<6;i++) { graphics.drawString("*********************************************",0,5*(i+2)); } // 生成随机数(6个字母) String sRand=""; int len=4;//四位 for (int i=0;i<len;i++) { int nRand = random.nextInt(set.length); String subRand= set[nRand]; sRand += subRand; // 设置字体的随机颜色 graphics.setColor(getRandColor(random,10,150)); // 设置随机字体及大小 graphics.setFont(new Font(fontTypes[random.nextInt(fontTypes.length)],Font.BOLD,18 + random.nextInt(6))); // 将此字母画到图片上 graphics.drawString(subRand, 17*i, 18); } // 将认证码存入session HttpSession session = request.getSession(); session.setAttribute("rand",sRand); Log.debug("生成的验证码为：" + (String)session.getAttribute("rand")); // 输出图象到页面 graphics.dispose(); ImageIO.write(image, "JPEG", response.getOutputStream()); response.getOutputStream().flush(); response.getOutputStream().close(); } public Color getRandColor(Random random,int fc,int bc) { if(fc > 255) fc = 255; if(bc > 255) bc = 255; int r = fc + random.nextInt(bc - fc); int g = fc + random.nextInt(bc - fc); int b= fc + random.nextInt(bc - fc); return new Color(r,g,b); } }