jsp登陆验证，网页登陆验证带验证码校验，登录功能之添加验证码
part_1：专门用于生成一个验证码图片的类:verificationcode.java
package cn.mike.javase.test;
import java.awt.color;
import java.awt.font;
import java.awt.graphics2d;
import java.awt.image.bufferedimage;
import java.io.file;
import java.io.filenotfoundexception;
import java.io.fileoutputstream;
import java.io.ioexception;
import java.io.outputstream;
import java.util.random;
import javax.imageio.imageio;
import org.junit.test;
/**
* @author : administrator
* @function : 这是用来测试随机生成验证码图片的类；
*/
public class verificationcode {
/**
* 单元测试，试一下能不能自动生成验证码图片
*/
// 这个函数是单元测试时使用的，这里private一下外面就调用不到了；
/* @test */
/* public */private void test_fun() {
verificationcode vc = new verificationcode();
bufferedimage image = vc.getimage();
try {
// 生成验证码图片，并保存到指定的路径
verificationcode.output(image, new fileoutputstream(new file(
".\image\vcode_2.jpg")));
} catch (filenotfoundexception e) {
e.printstacktrace();
}
// 将随机生成的文本内容输出到控制台，用于校验
system.out.println(vc.gettext());
}
private int w = 70;// 宽
private int h = 35;// 高
private string text;// 文本内容(验证码字符串)
private random r = new random();
private string[] fontnames = { "宋体", "华文楷体", "黑体", "微软雅黑", "楷体_gb2312" };
// 随机字符集合中不包括0和o，o，1和l，因为这些不易区分
private string codes = "23456789abcdefghijkmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyxz";
// 验证码图片的背景色：白色
private color bgcolor = new color(255, 255, 255);
/**
* 返回一个验证码图片buffer对象：bufferedimage
*/
public bufferedimage getimage() {
bufferedimage image = createimage();
// 获取绘图环境（画笔工具）
graphics2d g2 = (graphics2d) image.getgraphics();
// sb ： 用来保存验证码字符串文本内容
stringbuilder sb = new stringbuilder();
for (int i = 0; i < 4; ++i) {// 随机生成4个字符
string s = randomchar() + "";
sb.append(s);
float x = i * 1.0f * w / 4;
g2.setfont(randomfont());
g2.setcolor(randomcolor());
g2.drawstring(s, x, h - 5);
}
this.text = sb.tostring();// 记录验证码文本内容
drawline(image);// 画干扰线
return image;
}
/**
* @return 获取验证码文本内容
*/
public string gettext() {
return text;
}
/**
* @param image
* @param out
* 将文本写到指定的输出流。比如本测试中fileoutputstream指定的保存路径
*/
public static void output(bufferedimage image, outputstream out) {
try {
imageio.write(image, "jpeg", out);
} catch (ioexception e) {
e.printstacktrace();
}
}
private void drawline(bufferedimage image) {
graphics2d g2 = (graphics2d) image.getgraphics();
for (int i = 0; i < 3; ++i) {// 画3条干扰线
int x1 = r.nextint(w);
int y1 = r.nextint(h);
int x2 = r.nextint(w);
int y2 = r.nextint(h);
g2.setcolor(color.blue);
g2.drawline(x1, y1, x2, y2);
}
}
private color randomcolor() {
int red = r.nextint(150);
int green = r.nextint(150);
int blue = r.nextint(150);
return new color(red, green, blue);
}
private font randomfont() {
int index = r.nextint(fontnames.length);
string fontname = fontnames[index];
int style = r.nextint(4);
int size = r.nextint(5) + 24;
return new font(fontname, style, size);
}
private char randomchar() {
int index = r.nextint(codes.length());
return codes.charat(index);
}
private bufferedimage createimage() {
bufferedimage image = new bufferedimage(w, h,
bufferedimage.type_int_rgb);
graphics2d g2 = (graphics2d) image.getgraphics();
g2.setcolor(this.bgcolor);
g2.fillrect(0, 0, w, h);
return image;
}
}
part_2:登录界面：login.jsp
<%@ page language="java" import="java.util.*" pageencoding="utf-8"%>
<%
string path = request.getcontextpath();
string basepath = request.getscheme() + "://"
+ request.getservername() + ":" + request.getserverport()
+ path + "/";
%>
<!doctype html public "-//w3c//dtd html 4.01 transitional//en">
<html>
<head>
<base href="<%=basepath%>">
<title>my jsp 'login.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="this is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
<script type="text/javascript">
function _change_verity_code() {
var imgelem = document.getelementbyid("img_src");
//添加一个请求参数a是因为，通常浏览器都有缓存，点击换一张的时候没反应，所以加一个请求参数，获取当前请求时间，可以精确到毫秒，所以每次请求的参数都不同，所以浏览器有缓存也不妨碍；
imgelem.src = "/servletdemoproject/servlet/getverificationcodeservlet?a="
+ new date().gettime();
}
</script>
</head>
<%
string fdbkmsg = (string) request.getattribute("fdbkmsg");
if (null == fdbkmsg) {
fdbkmsg = "";
}
%>
<%
boolean logedin = (boolean) session.getattribute("logedin");
if (null == logedin) {
logedin = false;
} else if (logedin) {
//如果在本次会话已经登陆，直接重定向到success-page-1
response
.sendredirect("/servletdemoproject/login-demo/success-page-1.jsp");
}
%>
<%
string username = "";
cookie[] cookies = request.getcookies();
if ((null != cookies) && (cookies.length > 0)) {
for (cookie c : cookies) {
if ("admin".equals(c.getvalue())) {
username = "admin";
break;
}
}
}//end if-condition
%>
<body>
<br>
<div align="center">
请登录:
<br>
<form action="/servletdemoproject/servlet/loginverificationservlet"
method="post">
<div>
用户名：
<input type="text" name="username" value="<%=username%>" />
<br>
</div>
<div>
密 码：
<input type="password" name="password" />
<br>
</div>
<div>
验证码：
<input type="text" name="code_text" size="3" />
<img src="/servletdemoproject/servlet/getverificationcodeservlet"
id="img_src" />
<a href="javascript:_change_verity_code()">换一张</a>
<br>
</div>
<div>
<font color='red'><%=fdbkmsg%></font>
<br>
</div>
<div>
<input type="submit" value="提交" />
<br>
</div>
</form>
</div>
</body>
</html>
part_3:处理登录校验的servlet ：loginverificationservlet.java
package cn.mike.servlet.test_1212;
import java.awt.image.bufferedimage;
import java.io.ioexception;
import javax.servlet.servletexception;
import javax.servlet.http.httpservlet;
import javax.servlet.http.httpservletrequest;
import javax.servlet.http.httpservletresponse;
import cn.mike.javase.test.verificationcode;
public class getverificationcodeservlet extends httpservlet {
private static final long serialversionuid = -3520994675366100452l;
public void doget(httpservletrequest request, httpservletresponse response)
throws servletexception, ioexception {
// 1.新建一个verificationcode类；
verificationcode vc = new verificationcode();
// 2.从verificationcode类中获取bufferedimage对象；
bufferedimage bufimage = vc.getimage();
// 3.同时获取验证码中的文本内容，并放到session域中， 用于校验；
string code_text = vc.gettext();
request.getsession().setattribute("code_text", code_text);
// 4.将生成的图片输出到客户端浏览器
verificationcode.output(bufimage, response.getoutputstream());
}// end method-doget
public void dopost(httpservletrequest request, httpservletresponse response)
throws servletexception, ioexception {
// do same as get-method :
doget(request, response);
}// end method-dopost
}
part_4:成功登陆后的提示界面1：success-page-1.jsp
<%@ page language="java" import="java.util.*" pageencoding="utf-8"%>
<%
string path = request.getcontextpath();
string basepath = request.getscheme() + "://"
+ request.getservername() + ":" + request.getserverport()
+ path + "/";
%>
<!doctype html public "-//w3c//dtd html 4.01 transitional//en">
<html>
<head>
<base href="<%=basepath%>">
<title>my jsp 'success-page-1.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="this is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<%
string username = (string) session.getattribute("username");
if (null == username) {
//如果username为空值，说明不是通过正常渠道来的，转发到login页面；
request.setattribute("fdbkmsg", "别想走后门进来，赶紧登录！");
request.getrequestdispatcher("/login-demo/login.jsp").forward(
request, response);
}
%>
<body>
<br>
<%=username%>已经成功登陆。
<br>
<font>您可以选择浏览：</font>
<br>
<a href="/servletdemoproject/login-demo/success-page-2.jsp">点这儿有精彩.</a>
<br>
<a href="/servletdemoproject/login-demo/success-page-2.jsp">点这儿更精彩.</a>
<br />
<a href="/servletdemoproject/login-demo/success-page-2.jsp">你敢点这儿吗.</a>
<br />
</body>
</html>
part_5:成功登陆后的提示界面1：success-page-2.jsp
<%@ page language="java" import="java.util.date" pageencoding="utf-8"%>
<%@ page language="java" import="java.text.simpledateformat"%>
<%
string path = request.getcontextpath();
string basepath = request.getscheme() + "://"
+ request.getservername() + ":" + request.getserverport()
+ path + "/";
%>
<!doctype html public "-//w3c//dtd html 4.01 transitional//en">
<html>
<head>
<base href="<%=basepath%>">
<title>my jsp 'success-page-2.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="this is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<%
string username = (string) session.getattribute("username");
if (null == username) {
request.setattribute("fdbkmsg", "呵呵嗒，这里是你来的地方吗？快登陆！");
//转发到登录界面:
request.getrequestdispatcher("/login-demo/login.jsp").forward(
request, response);
}
simpledateformat sdateformat = new simpledateformat("a");
date today = new date();
string am_pm_str = sdateformat.format(today);
string am_pm_str_in_chinese = "";
if ("am".equalsignorecase(am_pm_str)) {
am_pm_str_in_chinese = "上午";
} else
am_pm_str_in_chinese = "下午";
// set null;
sdateformat = null;
today = null;
am_pm_str = null;
%>
<body>
<br />
<font><b><%=username%><%=am_pm_str_in_chinese%>好，能来到页面2真不简单.</b>
</font>
</body>
</html>
以上所述是小编给大家介绍的jsp实现登录功能之添加验证码，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对硕编程网站的支持！
【说明】：本文章由站长整理发布，文章内容不代表本站观点，如文中有侵权行为，请与本站客服联系(QQ:254677821)！