jquery实现无刷新验证码的简单实例_jquery

1. 思路:

页面上的验证码图片是servlet,采用jquery实现异步校验信息

2. 所用到的文件

/Uploads/verifyCodeServlet.java --用于生成图片的servlet

ResultServlet.java --用于校验验证码正确性的servlet

verifyCode.js --校验的js文件

jquery.js --jquery包里的源文件

verifyCode.jsp --页面

3. 代码

/Uploads/verifyCodeServlet.java

Java代码

import java.awt.Color; 
import java.awt.Font; 
import java.awt.Graphics2D; 
import java.awt.image.BufferedImage; 
import java.util.Random; 
 
import javax.imageio.ImageIO; 
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; 
 
public class /Uploads/verifyCodeServlet extends HttpServlet { 
 
 // 验证码图片的宽度。 
 private int width = 60; 
 
 // 验证码图片的高度。 
 private int height = 20; 
 
 // 验证码字符个数 
 private int codeCount = 4; 
 
 private int x = 0; 
 
 // 字体高度 
 private int fontHeight; 
 
 private int codeY; 
 
 char[] codeSequence = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 
 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 
 'X', 'Y', 'Z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' }; 
 
 /** 
 * 初始化验证图片属性 
 */ 
 public void init() throws ServletException { 
 // 从web.xml中获取初始信息 
 // 宽度 
 String strWidth = this.getInitParameter("width"); 
 // 高度 
 String strHeight = this.getInitParameter("height"); 
 // 字符个数 
 String strCodeCount = this.getInitParameter("codeCount"); 
 
 // 将配置的信息转换成数值 
 try { 
 if (strWidth != null && strWidth.length() != 0) { 
 width = Integer.parseInt(strWidth); 
 } 
 if (strHeight != null && strHeight.length() != 0) { 
 height = Integer.parseInt(strHeight); 
 } 
 if (strCodeCount != null && strCodeCount.length() != 0) { 
 codeCount = Integer.parseInt(strCodeCount); 
 } 
 } catch (NumberFormatException e) { 
 } 
 
 x = width / (codeCount + 1); 
 fontHeight = height - 2; 
 codeY = height - 4; 
 
 } 
 
 protected void service(HttpServletRequest req, HttpServletResponse resp) 
 throws ServletException, java.io.IOException { 
 
 // 定义图像buffer 
 BufferedImage buffImg = new BufferedImage(width, height, 
 BufferedImage.TYPE_INT_RGB); 
 Graphics2D g = buffImg.createGraphics(); 
 
 // 创建一个随机数生成器类 
 Random random = new Random(); 
 
 // 将图像填充为白色 
 g.setColor(Color.WHITE); 
 g.fillRect(0, 0, width, height); 
 
 // 创建字体，字体的大小应该根据图片的高度来定。 
 Font font = new Font("Fixedsys", Font.PLAIN, fontHeight); 
 // 设置字体。 
 g.setFont(font); 
 
 // 画边框。 
 g.setColor(Color.BLACK); 
 g.drawRect(0, 0, width - 1, height - 1); 
 
 // 随机产生160条干扰线，使图象中的认证码不易被其它程序探测到。 
 g.setColor(Color.BLACK); 
 for (int i = 0; i < 160; 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); 
 } 
 
 // randomCode用于保存随机产生的验证码，以便用户登录后进行验证。 
 StringBuffer randomCode = new StringBuffer(); 
 int red = 0, green = 0, blue = 0; 
 
 // 随机产生codeCount数字的验证码。 
 for (int i = 0; i < codeCount; i++) { 
 // 得到随机产生的验证码数字。 
 String strRand = String.valueOf(codeSequence[random.nextInt(36)]); 
 // 产生随机的颜色分量来构造颜色值，这样

输出的每位数字的颜色值都将不同。 red = random.nextInt(255); green = random.nextInt(255); blue = random.nextInt(255); // 用随机产生的颜色将验证码绘制到图像中。 g.setColor(new Color(red, green, blue)); g.drawString(strRand, (i + 1) * x, codeY); // 将产生的四个随机数组合在一起。 randomCode.append(strRand); } // 将四位数字的验证码保存到Session中。 HttpSession session = req.getSession(); session.setAttribute("validateCode", randomCode.toString()); // 禁止图像缓存。 resp.setHeader("Pragma", "no-cache"); resp.setHeader("Cache-Control", "no-cache"); resp.setDateHeader("Expires", 0); resp.setContentType("image/jpeg"); // 将图像输出到Servlet输出流中。 ServletOutputStream sos = resp.getOutputStream(); ImageIO.write(buffImg, "jpeg", sos); sos.close(); } } import java.awt.Color; import java.awt.Font; import java.awt.Graphics2D; import java.awt.image.BufferedImage; import java.util.Random; import javax.imageio.ImageIO; 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; public class /Uploads/verifyCodeServlet extends HttpServlet { // 验证码图片的宽度。 private int width = 60; // 验证码图片的高度。 private int height = 20; // 验证码字符个数 private int codeCount = 4; private int x = 0; // 字体高度 private int fontHeight; private int codeY; char[] codeSequence = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' }; /** * 初始化验证图片属性 */ public void init() throws ServletException { // 从web.xml中获取初始信息 // 宽度 String strWidth = this.getInitParameter("width"); // 高度 String strHeight = this.getInitParameter("height"); // 字符个数 String strCodeCount = this.getInitParameter("codeCount"); // 将配置的信息转换成数值 try { if (strWidth != null && strWidth.length() != 0) { width = Integer.parseInt(strWidth); } if (strHeight != null && strHeight.length() != 0) { height = Integer.parseInt(strHeight); } if (strCodeCount != null && strCodeCount.length() != 0) { codeCount = Integer.parseInt(strCodeCount); } } catch (NumberFormatException e) { } x = width / (codeCount + 1); fontHeight = height - 2; codeY = height - 4; } protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, java.io.IOException { // 定义图像buffer BufferedImage buffImg = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); Graphics2D g = buffImg.createGraphics(); // 创建一个随机数生成器类 Random random = new Random(); // 将图像填充为白色 g.setColor(Color.WHITE); g.fillRect(0, 0, width, height); // 创建字体，字体的大小应该根据图片的高度来定。 Font font = new Font("Fixedsys", Font.PLAIN, fontHeight); // 设置字体。 g.setFont(font); // 画边框。 g.setColor(Color.BLACK); g.drawRect(0, 0, width - 1, height - 1); // 随机产生160条干扰线，使图象中的认证码不易被其它程序探测到。 g.setColor(Color.BLACK); for (int i = 0; i < 160; 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); } // randomCode用于保存随机产生的验证码，以便用户登录后进行验证。 StringBuffer randomCode = new StringBuffer(); int red = 0, green = 0, blue = 0; // 随机产生codeCount数字的验证码。 for (int i = 0; i < codeCount; i++) { // 得到随机产生的验证码数字。 String strRand = String.valueOf(codeSequence[random.nextInt(36)]); // 产生随机的颜色分量来构造颜色值，这样输出的每位数字的颜色值都将不同。 red = random.nextInt(255); green = random.nextInt(255); blue = random.nextInt(255); // 用随机产生的颜色将验证码绘制到图像中。 g.setColor(new Color(red, green, blue)); g.drawString(strRand, (i + 1) * x, codeY); // 将产生的四个随机数组合在一起。 randomCode.append(strRand); } // 将四位数字的验证码保存到Session中。 HttpSession session = req.getSession(); session.setAttribute("validateCode", randomCode.toString()); // 禁止图像缓存。 resp.setHeader("Pragma", "no-cache"); resp.setHeader("Cache-Control", "no-cache"); resp.setDateHeader("Expires", 0); resp.setContentType("image/jpeg"); // 将图像输出到Servlet输出流中。 ServletOutputStream sos = resp.getOutputStream(); ImageIO.write(buffImg, "jpeg", sos); sos.close(); } }

ResultServlet.java

Java代码

import java.io.IOException; 
import java.io.PrintWriter; 
 
import javax.servlet.ServletException; 
import javax.servlet.http.HttpServlet; 
import javax.servlet.http.HttpServletRequest; 
import javax.servlet.http.HttpServletResponse; 
 
public class ResultServlet extends HttpServlet { 
 
 /** 
 * The doGet method of the servlet. 
 
 * 
 * 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 { 
 
 doPost(request, response); 
 } 
 
 /** 
 * The doPost method of the servlet. 
 
 * 
 * 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 { 
 
 response.setContentType("text/html;charset=utf-8"); 
 String validateC = (String) request.getSession().getAttribute("validateCode"); 
 String veryCode = request.getParameter("c"); 
 PrintWriter out = response.getWriter(); 
 if(veryCode==null||"".equals(veryCode)){ 
 out.println("验证码为空"); 
 }else{ 
 if(validateC.equals(veryCode)){ 
 out.println("验证码正确"); 
 }else{ 
 out.println("验证码错误"); 
 } 
 } 
 out.flush(); 
 out.close(); 
 } 
 
} 
import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class ResultServlet extends HttpServlet {

 /**
 * The doGet method of the servlet. 

 *
 * 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 {

 doPost(request, response);
 }

 /**
 * The doPost method of the servlet. 

 *
 * 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 {

 response.setContentType("text/html;charset=utf-8");
 String validateC = (String) request.getSession().getAttribute("validateCode");
 String veryCode = request.getParameter("c");
 PrintWriter out = response.getWriter();
 if(veryCode==null||"".equals(veryCode)){
 out.println("验证码为空");
 }else{
 if(validateC.equals(veryCode)){
 out.println("验证码正确");
 }else{
 out.println("验证码错误");
 }
 }
 out.flush();
 out.close();
 }

}

verifyCode.js

Js代码

verifyCode.jsp

Html代码

<%@ page language="java" contentType="text/html; charset=UTF-8" 
 pageEncoding="UTF-8"%>