验证码生成
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2022-03-03 08:33:35
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package sfca.util;
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.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import org.apache.commons.lang.RandomStringUtils;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
public class VerifyCode extends HttpServlet {
/**
*
*/
private static final long serialVersionUID = 1L;
private int length = 4; // 设置默认生成4个数字
private int width = 60; // 设置图象宽度
private int height = 20; // 设置图象高度
private Font mFont = new Font("Fixedsys", Font.PLAIN, 18); // 设置字体
/**
* Constructor of the object.
*/
public VerifyCode() {
super();
}
/**
* Destruction of the servlet. <br>
*/
public void destroy() {
super.destroy(); // Just puts "destroy" string in log
// Put your code here
}
private Color getRandColor(int fc, int bc) {// 给定范围获得随机颜色
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);
}
/**
* The doGet method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to get.
*
* @param request
* the request send by the client to the server
* @param response
* the response send by the server to the client
* @throws ServletException
* if an error occurred
* @throws IOException
* if an error occurred
*/
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
HttpSession session = request.getSession(false);
response.setContentType("image/jpeg"); // 必须设置ContentType为image/jpeg
// 设置页面不缓存
response.addHeader("pragma", "NO-cache");
response.addHeader("Cache-Control", "no-cache");
response.addDateHeader("Expries", 0);
String sessionName = Utils.dealNull(request.getParameter("type"));
sessionName = Utils.htmlEncode(sessionName);
if (sessionName == null || "".equals(sessionName)) {
sessionName = "smasungsms";
}
// 在内存中创建图象
BufferedImage image = new BufferedImage(width, height,
BufferedImage.TYPE_INT_RGB); // 设置图片大小的
// 获取图形上下文
Graphics g = image.getGraphics();
g.setColor(getRandColor(200, 250)); // 设置背景色
g.fillRect(0, 0, width, height);
// 设定字体
g.setColor(Color.black); // 设置字体色
g.setFont(mFont);
// 画边框
// g.setColor(new Color());
// g.drawRect(0,0,width-1,height-1);
// 生成随机类
Random random = new Random();
// 随机产生155条干扰线,使图象中的认证码不易被其它程序探测到
g.setColor(getRandColor(160, 200));
for (int i = 0; i < 155; 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);
}
// 取随机产生的认证码(4位数字)
String strRandom = RandomStringUtils.randomAlphanumeric(length)
.toLowerCase();
for (int i = 0; i < length; i++) {
String rand = String.valueOf(strRandom.substring(i, i + 1));
// 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)));
// 调用函数出来的颜色相同,可能是因为种子太接近,所以只能直接生成
g.drawString(rand, 13 * i + 6, 16);
}
// 将认证码存入SESSION
if (session == null)
session = request.getSession(true);
session.setAttribute(sessionName, strRandom);
// 图象生效
g.dispose();
//response.reset();
// 输出图象到页面
//ImageIO.write(image, "JPEG", response.getOutputStream());
ServletOutputStream responseOutputStream = response.getOutputStream();
JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(responseOutputStream);
encoder.encode(image);
//关闭流
responseOutputStream.flush();
responseOutputStream.close();
}
/**
* The doPost method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to
* post.
*
* @param request
* the request send by the client to the server
* @param response
* the response send by the server to the client
* @throws ServletException
* if an error occurred
* @throws IOException
* if an error occurred
*/
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
/**
* Initialization of the servlet. <br>
*
* @throws ServletException
* if an error occure
*/
public void init() throws ServletException {
// Put your code here
}
}
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