자바 인증 코드 생 성

import java.awt.Color;
import java.awt.Font;
import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;

import javax.imageio.ImageIO;
import javax.servlet.Servlet;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.lang.math.RandomUtils;

import nl.captcha.Captcha;
import nl.captcha.Captcha.Builder;
import nl.captcha.gimpy.BlockGimpyRenderer;
import nl.captcha.text.producer.ChineseTextProducer;
import nl.captcha.text.producer.DefaultTextProducer;
import nl.captcha.text.renderer.DefaultWordRenderer;
import nl.captcha.text.renderer.WordRenderer;



public class CaptchaServlet extends HttpServlet implements Servlet {
	private static final long serialVersionUID = 1L;
	private static final String PARAM_HEIGHT = "height"; //       50

	private static final String PARAM_WIDTH = "width";//       200

	private static final String PAEAM_NOISE = "noise";//               

	private static final String PAEAM_TEXT = "text";//   

	protected int _width = 150;
	protected int _height = 40;
	protected boolean _noise = false;
	protected String _text = "number:1,word:1,number:1,number:1,word:1";

	/**
	 *       .            
	 * 
	 * @throws ServletException
	 */
	@Override
	public void init() throws ServletException {
		if (getInitParameter(PARAM_HEIGHT) != null) {
			_height = Integer.valueOf(getInitParameter(PARAM_HEIGHT));
		}

		if (getInitParameter(PARAM_WIDTH) != null) {
			_width = Integer.valueOf(getInitParameter(PARAM_WIDTH));
		}

		if (getInitParameter(PAEAM_NOISE) != null) {
			_noise = Boolean.valueOf(getInitParameter(PAEAM_NOISE));
		}

		if (getInitParameter(PAEAM_NOISE) != null) {
			_text = String.valueOf(getInitParameter(PAEAM_TEXT));
		}
	}

	/**
	 *          get  
	 */
	@Override
	public void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

		Builder builder = new Captcha.Builder(_width, _height);
		//     
		// builder.addBorder();
		//         
		if (_noise == true) {
			builder.addNoise();
		}
		// ----------------       -----------
		//                             
		List<Font> fontList = new ArrayList<Font>();
		fontList.add(new Font("     ", Font.LAYOUT_NO_START_CONTEXT, 30));//          
		DefaultWordRenderer dwr = new DefaultWordRenderer(getRandomColor(), fontList);
		//                  

		WordRenderer wr = dwr;
		//     ，   5     .
		if (_text == null) {
			builder.addText();
		} else {
			String[] ts = _text.split(",");
			for (int i = 0; i < ts.length; i++) {
				String[] ts1 = ts[i].split(":");
				if ("chinese".equals(ts1[0])) {
					builder.addText(new ChineseTextProducer(Integer.parseInt(ts1[1])), wr);
				} else if ("number".equals(ts1[0])) {
					//     0 1           I O
					char[] numberChar = new char[] { '2', '3', '4', '5', '6', '7', '8' };
					builder.addText(new DefaultTextProducer(Integer.parseInt(ts1[1]), numberChar), wr);
				} else if ("word".equals(ts1[0])) {
					//     
					char[] numberChar = new char[] { 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'k', 'm', 'n', 'p', 'r',
							'w', 'x', 'y' };
					builder.addText(new DefaultTextProducer(Integer.parseInt(ts1[1]), numberChar), wr);
				} else {
					builder.addText(new DefaultTextProducer(Integer.parseInt(ts1[1])), wr);
				}
			}

		}

		// --------------    -------------
		//               form     ，to     
		// GradiatedBackgroundProducer gbp=new GradiatedBackgroundProducer();
		// gbp.setFromColor(Color.yellow);
		// gbp.setToColor(Color.red);
		//      ，        
		// FlatColorBackgroundProducer fbp=new
		// FlatColorBackgroundProducer(Color.red);
		//     --     
		// SquigglesBackgroundProducer sbp=new SquigglesBackgroundProducer();
		//        ,       
		// TransparentBackgroundProducer tbp = new
		// TransparentBackgroundProducer();

		// builder.addBackground(gbp);
		// ---------    ---------------
		//             3
		builder.gimp(new BlockGimpyRenderer(1));
		//           
		// builder.gimp(new RippleGimpyRenderer());
		//   --     
		// builder.gimp(new ShearGimpyRenderer(Color.red));
		//   --          ，          
		// builder.gimp(new FishEyeGimpyRenderer(Color.red,Color.yellow));
		//          3，75
		// builder.gimp(new DropShadowGimpyRenderer());
		//     
		Captcha captcha = builder.build();

		req.getSession().setAttribute("simpleCaptcha", captcha);
		resp.setHeader("Cache-Control", "private,no-cache,no-store");
		resp.setContentType("image/png");
		try {
			OutputStream os = resp.getOutputStream();
			ImageIO.write(captcha.getImage(), "png", os);
			os.close();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	public Color getRandomColor() {
		int n = RandomUtils.nextInt(100);

		if (n % 3 == 1) {
			return Color.RED;
		} else if (n % 3 == 2) {
			return Color.BLUE;
		}
		return Color.GREEN;
	}
}