java验证码

import java.awt.Color;import java.awt.Font;import java.awt.Graphics;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;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;@Controller@RequestMapping("/siteweb/validateCode/default.do")public class ValidateCodeController extends HttpServlet {    private static final long serialVersionUID = 1L;    private final int TYPE_NUMBER = 0;    private final int TYPE_LETTER = 1;    private final int TYPE_MULTIPLE = 2;    private int width;    private int height;    private int count;    private int type;    private String validate_code;    private Random random;    private Font font;    private int line;    public void init(){width = 60;height = 15;count = 4;type = TYPE_LETTER;random = new Random();line = 200;    }        @RequestMapping(params = "method=getValidateCode")    public void getValidateCode(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {this.init();response.setHeader("Pragma", "No-cache");response.setHeader("Cache-Control", "no-cache");response.setDateHeader("Expires", 0);response.setContentType("image/jpeg");String reqCount = request.getParameter("count");String reqWidth = request.getParameter("width");String reqHeight = request.getParameter("height");String reqType = request.getParameter("type");if (reqCount != null && reqCount != "") {    this.count = Integer.parseInt(reqCount);}if (reqWidth != null && reqWidth != "") {    this.width = Integer.parseInt(reqWidth);}if (reqHeight != null && reqHeight != "") {    this.height = Integer.parseInt(reqHeight);}if (reqType != null && reqType != "") {    this.type = Integer.parseInt(reqType);}font = new Font("Courier New", Font.BOLD, width / count);BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);Graphics g = image.getGraphics();g.setColor(getRandColor(200, 250));g.fillRect(0, 0, width, height);g.setColor(getRandColor(160, 200));for (int i = 0; i < line; i++) {    int x = random.nextInt(width);    int y = random.nextInt(height);    int xl = random.nextInt(12);    int yl = random.nextInt(12);    g.drawLine(x, y, x + xl, y + yl);}g.setFont(font);validate_code = getValidateCode(count, type);HttpSession session = request.getSession(true);session.setAttribute("validate_code", validate_code);for (int i = 0; i < count; i++) {    g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));    int x = (int) (width / count) * i;    int y = (int) ((height + font.getSize()) / 2) - 5;    g.drawString(String.valueOf(validate_code.charAt(i)), x, y);}g.dispose();ImageIO.write(image, "JPEG", response.getOutputStream());    }    private Color getRandColor(int from, int to) {Random random = new Random();if (to > 255)    from = 255;if (to > 255)    to = 255;int rang = Math.abs(to - from);int r = from + random.nextInt(rang);int g = from + random.nextInt(rang);int b = from + random.nextInt(rang);return new Color(r, g, b);    }    private String getValidateCode(int size, int type) {StringBuffer validate_code = new StringBuffer();for (int i = 0; i < size; i++) {    validate_code.append(getOneChar(type));}return validate_code.toString();    }    private String getOneChar(int type) {String result = null;switch (type) {case TYPE_NUMBER:    result = String.valueOf(random.nextInt(10));    break;case TYPE_LETTER:    result = String.valueOf((char) (random.nextInt(26) + 65));    break;case TYPE_MULTIPLE:    if (random.nextBoolean()) {result = String.valueOf(random.nextInt(10));    } else {result = String.valueOf((char) (random.nextInt(26) + 97));    }    break;default:    result = null;    break;}if (result == null)    throw new NullPointerException("获取验证码出错!");return result;    }}