java编写的验证码
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; @SuppressWarnings("serial") public class CheckCodeImg extends HttpServlet { private Font mFont = new Font("Arial Black", Font.PLAIN, 16); public void init() throws ServletException { super.init(); } Color getRandColor(int fc,int bc) { Random random = new Random(); 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); System.out.println("http://www.ewuji.net/"); } private String getRandomChar() { int rand = (int)Math.round(Math.random() * 2); long itmp = 0; char ctmp = ’\u0000’; switch (rand) { case 1: itmp = Math.round(Math.random() * 25 + 65); ctmp = (char)itmp; return String.valueOf(ctmp); case 2: itmp = Math.round(Math.random() * 25 + 97); ctmp = (char)itmp; return String.valueOf(ctmp); default : itmp = Math.round(Math.random() * 9); return String.valueOf(itmp); } } public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setHeader("Pragma","No-cache"); response.setHeader("Cache-Control","no-cache"); response.setDateHeader("Expires", 0); response.setContentType("image/jpeg"); int width=150, height=30; BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); Graphics g = image.getGraphics(); Random random = new Random(); g.setColor(getRandColor(200,250)); g.fillRect(1, 1, width-1, height-1); g.setColor(new Color(102,102,102)); g.drawRect(0, 0, width-1, height-1); g.setFont(mFont); g.setColor(getRandColor(160,200)); for (int i=0;i<155;i++) { int x = random.nextInt(width - 1); int y = random.nextInt(height - 1); int xl = random.nextInt(6) + 1; int yl = random.nextInt(12) + 1; g.drawLine(x,y,x + xl,y + yl); } for (int i = 0;i < 70;i++) { int x = random.nextInt(width - 1); int y = random.nextInt(height - 1); int xl = random.nextInt(12) + 1; int yl = random.nextInt(6) + 1; g.drawLine(x,y,x - xl,y - yl); } String sRand=""; for (int i=0;i<6;i++) { String tmp = getRandomChar(); sRand += tmp; g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110))); g.drawString(tmp,15*i+10,15); } HttpSession session = request.getSession(true); session.setAttribute("rand",sRand); g.dispose(); ImageIO.write(image, "JPEG", response.getOutputStream()); } }
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