验证码生成类(RandomValidateCode .java)：
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.p_w_picpath.BufferedImage;
import java.util.Random;
import javax.p_w_picpathio.ImageIO;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
public class RandomValidateCode {
public static String validateCode = null;
public static final String RANDOMCODEKEY = "RANDOMVALIDATECODEKEY";// 放到session中的key
private Random random = new Random();
private String randString = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";// 随机产生的字符串
private int width = 80;// 图片宽
private int height = 26;// 图片高
private int lineSize = 40;// 干扰线数量
private int stringNum = 4;// 随机产生字符数量
/*
* 获得字体
*/
private Font getFont() {
return new Font("Fixedsys", Font.CENTER_BASELINE, 18);
}
/*
* 获得颜色
*/
private Color getRandColor(int fc, int bc) {
if (fc > 255)
fc = 255;
if (bc > 255)
bc = 255;
int r = fc + random.nextInt(bc - fc - 16);
int g = fc + random.nextInt(bc - fc - 14);
int b = fc + random.nextInt(bc - fc - 18);
return new Color(r, g, b);
}
/**
* 生成随机图片
*/
public void getRandcode(HttpServletRequest request,
HttpServletResponse response) {
HttpSession session = request.getSession();
// BufferedImage类是具有缓冲区的Image类,Image类是用于描述图像信息的类
BufferedImage p_w_picpath = new BufferedImage(width, height,BufferedImage.TYPE_INT_BGR);
Graphics g = p_w_picpath.getGraphics();// 产生Image对象的Graphics对象,改对象可以在图像上进行各种绘制操作
g.fillRect(0, 0, width, height);
g.setFont(new Font("Times New Roman", Font.ROMAN_BASELINE, 18));
g.setColor(getRandColor(110, 133));
// 绘制干扰线
for (int i = 0; i <= lineSize; i++) {
drowLine(g);
}
// 绘制随机字符
String randomString = "";
for (int i = 1; i <= stringNum; i++) {
randomString = drowString(g, randomString, i);
}
session.removeAttribute(RANDOMCODEKEY);
session.setAttribute(RANDOMCODEKEY, randomString);
validateCode = randomString.toUpperCase();
g.dispose();
try {
ImageIO.write(p_w_picpath, "JPEG", response.getOutputStream());// 将内存中的图片通过流动形式输出到客户端
} catch (Exception e) {
e.printStackTrace();
}
}
/*
* 绘制字符串
*/
private String drowString(Graphics g, String randomString, int i) {
g.setFont(getFont());
g.setColor(new Color(random.nextInt(101), random.nextInt(111), random.nextInt(121)));
String rand = String.valueOf(getRandomString(random.nextInt(randString.length())));
randomString += rand;
g.translate(random.nextInt(3), random.nextInt(3));
g.drawString(rand, 13 * i, 16);
return randomString;
}
/*
* 绘制干扰线
*/
private void drowLine(Graphics g) {
int x = random.nextInt(width);
int y = random.nextInt(height);
int xl = random.nextInt(13);
int yl = random.nextInt(15);
g.drawLine(x, y, x + xl, y + yl);
}
/*
* 获取随机的字符
*/
public String getRandomString(int num) {
return String.valueOf(randString.charAt(num));
}
}
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验证码生成Servlet(ImageServlet.java)：
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse; public class ImageServlet extends HttpServlet { private static final long serialVersionUID = 1L;public ImageServlet() {
super();
} 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.setContentType("p_w_picpath/jpeg");// 设置相应类型,告诉浏览器输出的内容为图片 response.setHeader("Pragma", "No-cache");// 设置响应头信息，告诉浏览器不要缓存此内容 response.setHeader("Cache-Control", "no-cache"); response.setDateHeader("Expire", 0); RandomValidateCode randomValidateCode = new RandomValidateCode(); try { randomValidateCode.getRandcode(request, response);// 输出图片方法 } catch (Exception e) { e.printStackTrace(); } }}-----------------------------------------------------------默默无闻的分割线-----------------------------------------------------------
配置web.xml
<servlet>
<servlet-name>ImageServlet</servlet-name> <servlet-class>com.shenzhen.management.util.verificationCode.ImageServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>ImageServlet</servlet-name> <url-pattern>/p_w_picpathServlet.servlet</url-pattern> </servlet-mapping>-----------------------------------------------------------默默无闻的分割线-----------------------------------------------------------
<script type="text/javascript">
function refresh(obj) { obj.src = "${pageContext.request.contextPath}/p_w_picpathServlet.servlet?"+Math.random(); }</script><title>Hello World</title></head><body> <form action="login" method="post"> 验证码： <input id="validatecode" name="validatecode" type="text" /> <img title="看不清楚,换一张？" style="cursor: pointer;" οnclick="javascript:refresh(this);" src="${pageContext.request.contextPath}/p_w_picpathServlet.servlet"> <input type="submit" value = "提交"/> </form>-----------------------------------------------------------默默无闻的分割线-----------------------------------------------------------
private String validatecode;
public String login(){ this.message = student.getName(); Map session = ActionContext.getContext().getSession(); String genValidatecode = (String)session.get("RANDOMVALIDATECODEKEY"); //生成的验证码 System.out.println("validatecode:"+validatecode);//用户输入的验证码}
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需要注意的两个问题：1.配置servlet时，为servlet添加一个后缀(.servlet)，不然会被Struts2作为Action拦截。
2.调用servlet时，使用绝对路径调用。