最近公司的项目的登陆模块由我负责，所以就做了个登陆小功能进行练手，其包括了用jQuery对用户名和密码进行不为null验证，和出于安全性考虑加了一个验证码的校验
别的不说先上代码
controller层
CreateImage.java
package com.controller;
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.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 CreateImage extends HttpServlet {
/**
*
*/
private static final long serialVersionUID = 1L;
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// 获取session
HttpSession session = null;
// 控制图片不被缓存
response.setHeader("expires", -1+"");
response.setHeader("cache-control", "no-cache");
response.setHeader("pragma", "no-cache");
// 在内存中创建一个图片对象
BufferedImage image = new BufferedImage(80,20,BufferedImage.TYPE_INT_RGB);
// 设置图片
Graphics gra = image.getGraphics();
// 设置背景
gra.setColor(Color.BLACK);
gra.fillRect(0, 0, 80, 20);
// 设置字体和颜色
gra.setColor(Color.WHITE);
gra.setFont(new Font(null,Font.BOLD,14));
// 给图片上绘制随机的数据
String code = createStr(4);
gra.drawString(code, 5, 15);
// 存储到session
session = request.getSession(true);
session.setAttribute("code", code);
// 获取字节输出流
ServletOutputStream out = response.getOutputStream();
// 输出图片到浏览器客户端
ImageIO.write(image, "jpg", out);
// 释放资源
out.close();
// 目标是生成一个图片【数字和文本】
}
private String createStr(int i) {
// 定义随机数据的范围
String data = "ABCDEFGHJKLMNabcretfghwYyk1234567890";
// 定义一个随机对象
Random random = new Random();
// 定义可变的字符串缓冲区对象
StringBuffer sb = new StringBuffer();
// 循环
for (int j = 0; j < i; j++) {
int index = random.nextInt(data.length() - 1);
char c = data.charAt(index);
sb.append(c);
}
return sb.toString();
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
this.doGet(request, response);
}
}
该java代码创建一个image对象，也就是画一个图，图的上面添加了4（注：这4不是固定的，可以是5,6,7等，随你定）个随机数，再把这个验证码code放到session域中
在登陆验证的时候与jsp页面传过来的验证码进行校验，相等的话就验证成功。
下面是登陆页面：
login.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>登陆</title>
<script type="text/javascript" src="js/jquery-1.3.2.min.js"></script>
<script type="text/javascript" src="js/jquery.validate.js"></script></head>
<script type="text/javascript">
$(function(){
$("form").validate({
debug : false,
rules : {
name : {
required : true,
},
password : {
required : true
}
},
messages : {
name : {
required : "用户名不能为空!",
},
password : {
required : "密码不能为空!"
}
}
});
});
</script>
<body>
<center>
<h1>登陆页面</h1>
<form action="login.action" method="post">
用户名:<input type="text" name="name"><br>
密 码:<input type="password" name="password"><br>
验证码:<input type="text" name="code" /><br>
<img src="${pageContext.request.contextPath}/CreateImage"/> <a href="loginForward.action">看不清,换一张</a><br>
<input type="submit" value="登陆">
</form>
<h2><font color="red">${error }</font></h2>
</center>
</body>
</html>
以上代码有js验证，可以无刷新的校验用户和密码是否为空。（注：需要添加jquery-1.3.2.min.js和jquery.validate.js两个插件）这里很有趣，我遇到了一个问题（以前都没注意），那就是这两个插件调用的时候是要有顺序的，jquery-1.3.2.min.js要放在jquery.validate.js前面，才能生效。
UserController.java
package com.controller;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.List;
import java.util.Random;
import javax.ejb.CreateException;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import com.bean.User;
import com.dao.UserDaoImpl;
/**
* 基于注解的SpringMVC+ibatis的CRUD
* @author Saiteam
*
*/
@Controller
public class UserController {
private UserDaoImpl userDao = new UserDaoImpl();
@RequestMapping(value="/list.action")
public String list(HttpServletRequest request) throws Exception{
List<User> user = userDao.list();
request.setAttribute("users", user);
return "list";
}
@RequestMapping(value="/saveForward.action")
public String saveForward(HttpServletRequest request){
return "add";
}
@RequestMapping(value="/add.action")
public String add(HttpServletRequest request) throws Exception{
request.setCharacterEncoding("UTF-8");
User user = new User();
user.setName(request.getParameter("name"));
user.setPassword(request.getParameter("password"));
user.setSex(request.getParameter("sex"));
user.setAddress(request.getParameter("address"));
user.setPhone(request.getParameter("phone"));
user.setEmail(request.getParameter("email"));
userDao.save(user);
request.setAttribute("users", userDao.list());
return "list";
}
@RequestMapping(value="/delete.action")
public String delete(HttpServletRequest request) throws Exception{
int id = Integer.parseInt(request.getParameter("id"));
userDao.delete(id);
request.setAttribute("users", userDao.list());
return "list";
}
@RequestMapping(value="/update.action")
public String update(HttpServletRequest request) throws Exception{
request.setCharacterEncoding("UTF-8");
User user = new User();
user.setId(Integer.parseInt(request.getParameter("id")));
user.setName(request.getParameter("name"));
user.setPassword(request.getParameter("password"));
user.setSex(request.getParameter("sex"));
user.setAddress(request.getParameter("address"));
user.setPhone(request.getParameter("phone"));
user.setEmail(request.getParameter("email"));
userDao.update(user);
request.setAttribute("users", userDao.list());
return "list";
}
@RequestMapping(value="/get.action")
public String get(HttpServletRequest request) throws Exception{
int id = Integer.parseInt(request.getParameter("id"));
request.setAttribute("user", userDao.get(id));
return "update";
}
/*
* 登陆功能
*/
@RequestMapping(value="login.action")
public String login(HttpServletRequest request) throws Exception{
request.setCharacterEncoding("UTF-8");
String name = request.getParameter("name");
String password = request.getParameter("password");
String userCode = request.getParameter("code");
//测试
System.out.println("-------name-----------"+name);
System.out.println("-------password-----------"+password);
System.out.println("-------userCode-----------"+userCode);
User model = userDao.login(name, password);
//测试
System.out.println("-------------model--------"+model);
if(model != null && !model.equals("")){
//判断验证码是否为空
if(userCode==null || "".equals(userCode)){
request.setAttribute("error", "请填写验证码!");
return "forward:/login.jsp";
}
//从session中获取code验证码 1.先获取session
HttpSession session = request.getSession(false);
//判断session是否为空
if(session == null){
System.out.println("服务器session为null不处理添加用户的逻辑。");
return "forward:/login.jsp";
}
//2.获取session中的code
String serverCode = (String) session.getAttribute("code");
//判断
if(serverCode == null || "".equals(serverCode)){
System.out.println("服务器中的校验码为null不处理添加用户的逻辑!");
return "forward:/login.jsp";
}
//判断jsp页面传来的验证码与后台服务器session中带的验证码是否相等
if(userCode.equals(serverCode)){
request.setAttribute("users", userDao.list());
return "list";
}else{
request.setAttribute("error", "验证码错误！");
return "forward:/login.jsp";
}
}else{
request.setAttribute("error", "用户或密码错误！");
return "forward:/login.jsp";
}
}
//实现注册功能
@RequestMapping(value="register.action")
public String register(HttpServletRequest request) throws Exception{
request.setCharacterEncoding("UTF-8");
User user = new User();
user.setName(request.getParameter("name"));
user.setPassword(request.getParameter("password"));
user.setSex(request.getParameter("sex"));
user.setAddress(request.getParameter("address"));
user.setPhone(request.getParameter("phone"));
user.setEmail(request.getParameter("email"));
userDao.save(user);
return "forward:/index.jsp";
}
/**
* 跳转到登陆页面
* @param request
* @return
*/
@RequestMapping(value="loginForward.action")
public String loginForwad(HttpServletRequest request){
return "forward:/login.jsp";
}
/**
* 转发到注册页面
* @param request
* @return
*/
@RequestMapping(value="rgf.action")
public String registerForwad(HttpServletRequest request){
return "forward:/register.jsp";
}
}
我在controller层使用了SpringMVC框架，在DAO层使用了Ibatis框架，做了CRUD的功能，代码就比较乱了，该层获取浏览器传来的参数，包括name（用户名），password（密码）和code（验证码）,对他们进行校验，校验成功就能获得下一步的操作了。
以上仅仅是个人的一些经验，欢迎大家一起交流。
java登陆验证码与JS无刷新验证,布布扣,bubuko.com
原文：http://www.cnblogs.com/wcyBlog/p/3822841.html