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JavaWeb学习笔记——开发动态WEB资源（五）servlet身份验证

2015-07-04 18:22 639 查看

本工程的功能是实现Javaweb的servlet身份验证

一下是login.html文件中的代码

<!DOCTYPE html>
<html>
<head>
<title>login.html</title>

<meta name="keywords" content="keyword1,keyword2,keyword3">
<meta name="description" content="this is my page">
<meta name="content-type" content="text/html; charset=GBK">

<!--<link rel="stylesheet" type="text/css" href="./styles.css">-->

<script type="text/javascript">
function check(){
//获取控件内容
var loginname = document.getElementById("loginname").value;
if(loginname == ""){
alert("用户名不能为空");
document.getElementById("loginname").focus();//获取焦点
return false;
}

var password = document.getElementById("password").value;
if(password == ""){
alert("密码不能为空");
document.getElementById("password").focus();
return false;
}

//验证成功
document.loginform.submit();
}
</script>

</head>

<body>
<center>
<h2>登陆页面</h2>
<br>
<!-- html数据由两种传输方式 1.get 从地址栏传递 2.form表单传输
form代表表单
--action属性代表提交的url
action="login.do",那么在web.xml里面定义<servlet-mapping>的<url-pattern>
的时候也是login.do
--method属性代表提交表单的方式，http里面重点是get和post，默认get方式提交
--name属性给表单其名字
--id属性代表唯一标示该表单的名字，主要是javascript脚本使用
-->
<form action="login.do" method="get" name="loginform" id="loginform">
<table>
<tr>
<td>登录名：</td>
<td><input type="text" name="loginname" id="loginname"/></td>
</tr>
<tr>
<td>密码：</td>
<td><input type="password" name="password" id="password"/></td>
</tr>
</table>
<table>
<tr>
<td><input type="button" value="提交" onclick="check();"></td>
  
<td><input type="reset" value="重置"></td>
</tr>
</table>
</form>

</center>
</body>
</html>

以下代码是LoginServlet.java中的代码

package org.common.servlet;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.Enumeration;
import java.util.Properties;

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

public class LoginServlet extends HttpServlet {

/**
* Constructor of the object.
*/
public LoginServlet() {
super();
}

/**
* Destruction of the servlet. <br>
*/
public void destroy() {
super.destroy(); // Just puts "destroy" string in log
// Put your code here
}

/**
* The doGet method of the servlet. <br>
*
* 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 {

System.out.println("执行 doGet 方法...");
//        //1.接收前台传递过来的参数
//        Enumeration enums = request.getParameterNames();
//        while(enums.hasMoreElements()){
//            System.out.println(enums.nextElement());
//
//        }

//转换编码的第2种方式，配合doPost()方法使用
request.setCharacterEncoding("GBK");

//提交的name可以在后台使用request.getParameter("loginname")获取值
String loginname = request.getParameter("loginname");
System.out.println("转换前loginname:" + loginname);
//String password = request.getParameter("password");

//把loginname这个字符串转成GBK，前提你要确定编码
loginname = new String(loginname.getBytes("iso-8859-1"),"GBK");
System.out.println("转换后loginname:" + loginname);
String password = request.getParameter("password");

//properties文件是java的默认配置文件，以key-value的形式存储数据
//增加了一个user.properties文件存储用户名密码
Properties pro = new Properties();
//load方法从输入流中读取属性列表（键和元素对）
pro.load(this.getClass().getResourceAsStream("/user.properties"));
//System.out.print(pro);

response.setContentType("text/html;charset=GBK");
PrintWriter out = response.getWriter();
out.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");
out.println("<HTML>");
out.println("  <HEAD><TITLE>A Servlet</TITLE></HEAD>");
out.println("  <BODY>");

//out.print(" loginname: " + loginname);
//out.print(" password: " + password);
if(loginname.equals(pro.getProperty("loginname"))
&& password.equals(pro.getProperty("password"))){
out.println(" 欢迎["+pro.getProperty("username")+"]登陆");
}else{
out.println("用户名密码错误");
}

out.println("  </BODY>");
out.println("</HTML>");
out.flush();
out.close();
}

/**
* The doPost method of the servlet. <br>
*
* 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 {

this.doGet(request, response);
}

/**
* Initialization of the servlet. <br>
*
* @throws ServletException if an error occurs
*/
public void init() throws ServletException {
// Put your code here
}

}

doGet()方法不安全，所以尽量使用doPost()方法

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