package rd.test;import java.awt.Color;import java.awt.Font;import java.awt.Graphics;import java.awt.Graphics2D;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;//输出一张图片public class Test1 extends HttpServlet {	public static final int WIDTH = 120;	public static final int HEIGHT = 35;		public void doGet(HttpServletRequest request, HttpServletResponse response)			throws ServletException, IOException {				BufferedImage image = new BufferedImage(WIDTH,HEIGHT,BufferedImage.TYPE_INT_RGB);		Graphics g = image.getGraphics();				//1,设置背景色		setBackGround(g);				//2，设置边框		setBorder(g);				//3，画干扰线		drowRandomLine(g);				//4，写随机数		//drawRandomNum(g);		String random = drawRandomNum2d((Graphics2D)g);//验证相关　　　　　　　　　　request.getSession().setAttribute("checkcode",random);//验证相关		 		//5,图形写给浏览器		response.setContentType("image/jpeg");		//控制浏览器不要缓存随机验证码图片，让它每次都更新		response.setDateHeader("expries", -1);		response.setHeader("Cache-Control","no-cache");		response.setHeader("Pragma","no-cache");		ImageIO.write(image, "jpg", response.getOutputStream());	}	private void drowRandomLine(Graphics g) {		// TODO Auto-generated method stub		g.setColor(Color.GRAY);				for(int i = 0;i<5;i++) {			int x1 = new Random().nextInt(WIDTH-2)+2;			int y1 = new Random().nextInt(HEIGHT-2)+2;						int x2 = new Random().nextInt(WIDTH-2)+2;			int y2 = new Random().nextInt(HEIGHT-2)+2;						g.drawLine(x1, y1, x2, y2);		}	}	private String drawRandomNum2d(Graphics2D g) {		// TODO Auto-generated method stub		g.setColor(Color.RED);		g.setFont(new Font("宋体",Font.BOLD,20));		//[\u4e00-\u9fa5]				String base = "一二三四五六七八九十百千万兆亿啊我饿依无余";　　　　　　　　　　StringBuffer sb = new StringBuffer();//验证相关 		int x = 5;		for(int i = 0;i<4;i++) {			int degree = new Random().nextInt()%30;			String ch = "" + base.charAt(new Random().nextInt(base.length()));			sb.append(ch);//验证相关 　　　　　　　　　　　　　  g.rotate(degree*Math.PI/180, x, 25);//设置旋转幅度			g.drawString(ch, x, 25);			g.rotate(-degree*Math.PI/180, x, 25);//转回去			x+=30;		} 　　　　　　　　　　return sb.toString();	}	private void drawRandomNum(Graphics g) {		g.setColor(Color.RED);		g.setFont(new Font("宋体",Font.BOLD,20));		//[\u4e00-\u9fa5]				String base = "一二三四五六七八九十百千万兆亿啊我饿依无余";		int x = 5;		for(int i = 0;i<4;i++) {			String ch = "" + base.charAt(new Random().nextInt(base.length()));			g.drawString(ch, x, 20);			x+=30;		}			}	private void setBorder(Graphics g) {		g.setColor(Color.BLUE);		g.drawRect(1, 1, WIDTH-2, HEIGHT-2);			}	private void setBackGround(Graphics g) {		// TODO Auto-generated method stub		g.setColor(Color.WHITE);		g.fillRect(0, 0, WIDTH, HEIGHT);	}	public void doPost(HttpServletRequest request, HttpServletResponse response)			throws ServletException, IOException {	}}

 

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%>                  
         
         
             
         
         
                               
     
                用户名:
                密码 :
      
      
      
          验证码:
                
                
            
     
   

 

check:

 

request.setCharacterEncoding("UTF-8");

String c_checkcode = request.getParameter("checkcode");

String s_checkcode = request.getSession().getAttribut("checkcode");

if(c_checkcode!=null && s_checkcode!=null && c_checkcode.equals(s_checkcode)){

　　System.out.println("处理注册请求“);

}else{

　　System.out.println("验证码错误");

}