登录界面设置：
<?php
/**
* Created by xx.
* User: msi
* Date: 2017/10/26
* Time: 18:12
*/
//session每次用之前都要启用！！，用start！
session_start();
//var_dump($_SESSION);
?>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<form action="login_post.php" method="post">
<table>
<tr>
<td>用户名：</td>
<td><input type="text" name="uname" placeholder="请输入账号"></td>
</tr>
<tr>
<td>密码：</td>
<td><input type="password" name="pwod" placeholder="请输入密码"></td>
</tr>
</table>
<input type="submit" value="登录">
</form>
</body>
</html>
登录处理界面设置代码：
<?php
/**
* Created by xx.
* User: msi
* Date: 2017/10/26
* Time: 18:15
*/
session_start();
header("content-type:text/html; charset=utf-8");
require_once "../Public/DBDA.class.php";
$db = new DBDA();
//先查输入的用户名，再根据输入的用户名去数据库查密码,最后验证密码是否和Mysql里面的密码相匹配！
$sql = "select * from t_user WHERE uname = '{$_POST["uname"]}'and pwod = '{$_POST["pwod"]}'";
//只要不是1就行
$result = $db->strQuery($sql);
if ($result !="0"){
echo "登陆成功";
$_SESSION['user'] = array(
'uname'=>'user1',
);
// var_dump($_SESSION);
}else{
echo "登录失败";
}
//检测session信息->
如果session信息为空的话，那么就跳转登录界面
if (empty($_SESSION['user'])){
header("location:login.php");
}
//退出登录，销毁账号信息;
unset($_SESSION);
这样就完成啦！