验证码 随机旋转、字体、色彩

package servlet;

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GraphicsEnvironment;
import java.awt.geom.AffineTransform;
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;

public class SecurityCodeServlet extends HttpServlet {

	private Color getRandColor(int s, int e) {
		Random random = new Random();
		if (s > 255)
			s = 255;
		if (e > 255)
			e = 255;
		int r = random.nextInt(e - s) + s; // 随机生成RGB中的R值
		int g = random.nextInt(e - s) + s; // 随机生成RGB中的G值
		int b = random.nextInt(e - s) + s; // 随机生成RGB中的B值
		return new Color(r, g, b);
	}


	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		this.doPost(request, response);
	}

	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		response.setHeader("Pragma", "No-cache");
		response.setHeader("Cache-Control", "No-cache");
		response.setDateHeader("Expires", 0);
		//指定生成的响应图片
		response.setContentType("image/jpeg");
		int width = 150;							//指定生成验证码图片的宽度
		int heigh = 60;							//指定生成验证码图片的高度
			//获得图像数据缓冲对象
		BufferedImage bi = new BufferedImage(width,heigh,BufferedImage.TYPE_INT_RGB);
			//获得图形上下文的抽象基类
		Graphics g = bi.getGraphics();
		Random r = new Random();
		Font f = new Font("黑体",Font.PLAIN,60);	//定义字体样式
		g.setColor(getRandColor(200, 250));		//设置背景颜色
		g.fillRect(0, 0, width, heigh);			//绘制背景
		g.setFont(f);							//设置字体
		g.setColor(getRandColor(180, 200));		//设置前景颜色
		
		
		Graphics2D g2d = (Graphics2D) g;
		//画一条折线		
		BasicStroke bs=new BasicStroke(5f,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);	//创建一个供画笔选择线条粗细的对象
		g2d.setStroke(bs);				//改变线条的粗细
		g2d.setColor(Color.DARK_GRAY);		//设置当前颜色为预定义颜色中的深灰色
		int[] xPoints=new int[8];
		int[] yPoints=new int[8];
		for(int j=0;j<8;j++){
			xPoints[j]=r.nextInt(width - 1);
			yPoints[j]=r.nextInt(heigh - 1);
		}
		g2d.drawPolyline(xPoints, yPoints,8);
		
		String sRand = "";
		String ctmp = "";
		int itmp = 0;
		for (int i = 0; i < 6; i++) {
			switch (r.nextInt(2)) {
			case 1:
				itmp = r.nextInt(26) + 65; // 生成A~Z的字母
				ctmp = String.valueOf((char) itmp);
				break;
			default:
				itmp = r.nextInt(10) + 48; // 生成0~9的数字
				ctmp = String.valueOf((char) itmp);
				break;
			}
			sRand += ctmp;
			//设置每个字符的随机颜色
			Color color = new Color(20 + r.nextInt(210), 20 + r.nextInt(210), 20 + r.nextInt(210));
			g2d.setColor(color);
			//设置每个字符的随机字体
			g2d.setFont(this.getRandomFont());
			//设置每个字符的随机旋转
			AffineTransform at = new AffineTransform();
			int number = r.nextInt(3)-1;
			double role = number*r.nextDouble()*(Math.PI/4);
			at.setToRotation(role,25*i+5,55-r.nextInt(20)); //role:旋转角度,后面两个参数是设置围绕坐标点旋转
			g2d.setTransform(at);
			
			g2d.drawString(ctmp, 25*i+5,55-r.nextInt(20));
		}
			HttpSession session = request.getSession(true);
			session.setMaxInactiveInterval(5*60);//设置session对象5分钟失效
			session.setAttribute("code", sRand.toString());

			g2d.dispose();

			System.out.println(sRand);
			ImageIO.write(bi, "JPEG", response.getOutputStream());
			
			
	}
	
	
	 public static Font getRandomFont() {  
	        //String[] fonts = {"Georgia", "Verdana", "Arial", "Tahoma", "Time News Roman", "Courier New", "Arial Black", "Quantzite"};  
	        String[] fonts = {"a_TrianglerCmUp","Astarisborn","WishfulWaves"};
	        Random r = new  Random();
	        int fontIndex = r.nextInt(fonts.length);
	        return new Font(fonts[fontIndex],  r.nextInt(3),50-r.nextInt(20));  
	    }

}


把字体加入到操作系统中