CNG/WebRoot/yanzhengma.jsp

<%@ page contentType="image/jpeg" language="java" import="java.util.*,java.awt.*,java.awt.image.*,javax.imageio.*" pageEncoding="utf-8"%>

<%!
	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);
	}
%>

<% 
	//设置页面不缓存
	response.setHeader("Pragma","no-cache");
	response.setHeader("Cache-Control","no-catch");
	response.setDateHeader("Expires",0);
	
	//在内存中创建图象
	int width = 60;
	int height = 20;
	BufferedImage image = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
	//创建图象
	Graphics g = image.getGraphics();
	//生成随机对象
	Random random = new Random();
	//设置背景色
	g.setColor(getRandColor(200,250));
	g.fillRect(0,0,width,height);
	//设置字体
	g.setFont(new Font("Tines Nev Roman",Font.PLAIN,18));
	//随机产生干扰线
	g.setColor(getRandColor(160,200));
	for(int i = 0; i < 255; i++){
		int x = random.nextInt(width);
		int y = random.nextInt(height);
		int xl = random.nextInt(12);
		int yl = random.nextInt(12);
	}
	//随机产生认证码,4位数字
	String sRand = "";
	for(int i = 0; i < 4; i++){
		String rand = String.valueOf(random.nextInt(10));
		sRand  += rand;
		//将认证码显示到图象中
		g.setColor(new Color(20 + random.nextInt(110),20 + random.nextInt(110),20 + random.nextInt(110)));
		g.drawString(rand,13*i+6,16);
	}
	session.setAttribute("rCode",sRand);
	//图像生效
	g.dispose();
	//输出图像到页面
	ImageIO.write(image,"JPEG",response.getOutputStream());
	out.clear();
	out = pageContext.pushBody();
%>