jquery实现无刷新验证码的简单实例

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

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

VerifyCodeServlet.java

Java代码

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 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<a href="/tag/suiji/" target="_blank" class="keywords">随机</a>数<a href="/tag/shengcheng/" target="_blank" class="keywords">生成</a>器类  
Random random = new Random();  

// 将图像填充为白色  
g.setColor(Color.WHITE);  
g.fillRect(0,width,height);  

// 创建字体，字体的大小应该根据<a href="/tag/tupian/" target="_blank" class="keywords">图片</a>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,width - 1,height - 1);  

// <a href="/tag/suiji/" target="_blank" class="keywords">随机</a>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<a href="/tag/suiji/" target="_blank" class="keywords">随机</a>产生的验证码，以便<a href="/tag/yonghu/" target="_blank" class="keywords">用户</a><a href="/tag/denglu/" target="_blank" class="keywords">登录</a>后进行验证。  
StringBuffer randomCode = new StringBuffer();  
int red = 0,green = 0,blue = 0;  

// <a href="/tag/suiji/" target="_blank" class="keywords">随机</a>产生codeCount数字的验证码。  
for (int i = 0; i < codeCount; i++) {  
  // 得到<a href="/tag/suiji/" target="_blank" class="keywords">随机</a>产生的验证码数字。  
  String strRand = String.valueOf(codeSequence[random.nextInt(36)]);  
  // 产生<a href="/tag/suiji/" target="_blank" class="keywords">随机</a>的颜色分量来构造颜色值，这样<a href="/tag/shuchu/" target="_blank" class="keywords">输出</a>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<a href="/tag/suiji/" target="_blank" class="keywords">随机</a>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<a href="/tag/suiji/" target="_blank" class="keywords">随机</a>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());  

// <a href="/tag/jinzhi/" target="_blank" class="keywords">禁止</a>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<a href="/tag/shuchu/" target="_blank" class="keywords">输出</a>到Servlet<a href="/tag/shuchu/" target="_blank" class="keywords">输出</a>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;

public class 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','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,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,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",fontHeight);
// 设置字体。
g.setFont(font);

// 画边框。
g.setColor(Color.BLACK);
g.drawRect(0,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 + 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,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,blue));
g.drawString(strRand,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,sos);
sos.close();
}

}

ResultServlet.java

Java代码

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,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<a href="/tag/cuowu/" target="_blank" class="keywords">错误</a>");  
  }  
}  
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,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

=0)){ url = url + "×tamp=" + timestamp; }else{ url = url + "?timestamp=" + timestamp; } return url; }

function isRightCode(){
var code = $("#veryCode").attr("value");
code = "c=" + code;
$.ajax({
type:"POST",url:"resultServlet",data:code,success:callback
});
}

function callback(data){
$("#info").html(data);
}
function changeImg(){
var imgSrc = $("#imgObj");
var src = imgSrc.attr("src");
imgSrc.attr("src",chgUrl(src));
}
//时间戳
//为了使每次生成图片不一致，即不让浏览器读缓存，所以需要加上时间戳
function chgUrl(url){
var timestamp = (new Date()).valueOf();
url = url.substring(0,17);
if((url.indexOf("&")>=0)){
url = url + "×tamp=" + timestamp;
}else{
url = url + "?timestamp=" + timestamp;
}
return url;
}

function isRightCode(){
var code = $("#veryCode").attr("value");
code = "c=" + code;
$.ajax({
type:"POST",success:callback
});
}

function callback(data){
$("#info").html(data);
}

verifyCode.jsp

HTML代码

<Meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> test verify code

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jquery实现无刷新验证码的简单实例

1. 思路:

2. 所用到的文件

3. 代码

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