java验证码

<%@ page language="java" pageEncoding="UTF-8"%> <%@ page contentType="image/jpeg" import="java.awt.*,java.awt.image.*,java.util.*,javax.imageio.*" %> <%! public Color getColor(){ Random random = new Random(); int r = random.nextInt(256);//0-255 int g = random.nextInt(256); int b = random.nextInt(256); return new Color(r,g,b); } public String getNum(){ String str = ""; Random random = new Random(); for(int i=0;i<4;i++){ str += random.nextInt(10);//0-9 } return str; } %> <% response.setHeader("pragma", "mo-cache"); response.setHeader("cache-control", "no-cache"); response.setDateHeader("expires", 0); BufferedImage image = new BufferedImage(80,30,BufferedImage.TYPE_INT_RGB); Graphics g = image.getGraphics(); g.setColor(new Color(200,200,200)); g.fillRect(0,0,80,30); for (int i = 0; i < 30; i++) { Random random = new Random(); int x = random.nextInt(80); int y = random.nextInt(30); int xl = random.nextInt(x+10); int yl = random.nextInt(y+10); g.setColor(getColor()); g.drawLine(x, y, x + xl, y + yl); } g.setFont(new Font("serif", Font.BOLD,16)); g.setColor(Color.BLACK); String checkNum = getNum();//"2525" StringBuffer sb = new StringBuffer(); for(int i=0;i<checkNum.length();i++){ sb.append(checkNum.charAt(i)+" ");//"2 5 2 5" } g.drawString(sb.toString(),15,20); session.setAttribute("CHECKNUM",checkNum);//2525 ImageIO.write(image,"jpeg",response.getOutputStream()); out.clear(); out = pageContext.pushBody(); %>