java生成验证码

//生成验证码
import java.awt.Color;
import java.awt.Font;
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;

public class ImageCode extends HttpServlet {
	Random ran = new Random();
	int r,g,b;
	public void doGet(HttpServletRequest request, HttpServletResponse response) {
		doPost(request, response);
	}
	public void doPost(HttpServletRequest request, HttpServletResponse response) {
		response.setContentType("text/html;charset=utf-8");
		// 响应浏览器的是图片
		response.setContentType("image/jpeg");
		// 创建图片
		int width = 130;
		int height = 40;
		BufferedImage image = new BufferedImage(width, height,
				BufferedImage.TYPE_INT_BGR);
		// 得到图片的画笔
		Graphics2D brush = image.createGraphics();

		// 绘制图形 167,192,220
		brush.setColor(Color.white); // 填充图形背景色
		brush.fillRect(0, 0, width, height); // 填充的坐标

		// 绘制边框
		brush.setColor(Color.gray);
		brush.drawRect(0, 0, width - 1, height - 1);

		// 字符集
		String msg = "ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890abcdefghijklmnopqrstuvwxyz";
		// 画笔的字体,样式和大小
		Font f = new Font("楷体", Font.BOLD, 30);
		brush.setFont(f);

		int x = 15;
		brush.setColor(Color.red);
		for (int i = 0; i < 4; i++) {
			randomColor();
			Color c=new Color(r, g, b);
			brush.setColor(c); // 随机产生画笔颜色
			int index = ran.nextInt(msg.length()); // 在msg范围内产生下个随机数
			char ch = msg.charAt(index); // 通过索引得到任意一个字符
			String s = String.valueOf(ch); // 将字符转换成字符串

			int rad = ran.nextInt(80);	// 产生一个随机的度数
			double ra = radian(rad);	//把随机度数转换成弧度
			brush.rotate(ra, x, 15);	//根据弧度旋转图片
			brush.drawString(s, x, 30); // 把字符串写入到图片中,y轴位置保持不变
			brush.rotate(-ra, x, 15);	//把图片旋转回原来的位置
			x += 30; // x轴每次循环加30
			
		}
		//设置干扰线
		for(int k=0;k<18;k++){
			randomColor();
			Color c=new Color(r, g, b);
			brush.setColor(c); // 随机产生画笔颜色
			int x1 = ran.nextInt(150); 
			int y1 = ran.nextInt(40);
			int x2 = ran.nextInt(150);
			int y2 = ran.nextInt(40);
			brush.drawLine(x1, y1, x2, y2);
		}	
			try {
				ImageIO.write(image, "jpeg", response.getOutputStream());
			} catch (IOException e) {
				System.out.println(e);
			}
	}
	//产生随机颜色
	public void randomColor(){
		this.r = ran.nextInt(255); // 0~255是RGB的取值范围
		this.g = ran.nextInt(255);
		this.b = ran.nextInt(255);
	}
	// 弧度=2*PI*角度/360
	public double radian(int rad) {
		double d = 2 * 3.14 * rad / 360;
		return d;
	}	
}