一些基本的php代码

<?php
//是否显示错误及提示
//error_reporting(0);
//php 怎么判断一个接受到的参数是否为空
if(empty($_GET['f']) || !isset($_GET['f']) || $_GET['f']=='' || $_GET['f']==null){
$f=null;
echo "null";
}
if(isset($_GET['f'])){
	$f=$_GET["f"];
}
if($f=="info")
{
phpinfo(); // 调用函数
}
if($f=="conf")
{
conf(); 
}
if($f=="writef")
{
writef(); 
}
if($f=="dbc")
{
dbc(); 
}
if($f=="dbr")
{
dbr(); 
}
if($f=="dbsql")
{
dbsql(); 
}
if($f=="dbins")
{
dbins(); 
}
if($f=="dbu")
{
dbu(); 
}
if($f=="dbdel")
{
dbdel(); 
}
if($f=="sess")
{
sess(); 
}
if($f=="cooki")
{
cooki(); 
}
if($f=="fileup")
{
fileup(); 
}
//函数///////////////////////////////////////////////////////////////////////////////////
function info() {
  phpinfo();
}
//读取配置文件
function conf() {	
  $config = include('config.php');
var_dump($config);
}
//写文件 
function writef() {	
$myconf = fopen("config.php", "w") or die("Unable to open file!");
$ar=array(
    'a' => 1,
    'b' => 2
);
$arr=var_export($ar,true);//不加true会在页面显示
fwrite($myconf, $arr);
fclose($myconf);
echo "write config.php";
}
//创建数据库
function dbc() {
//$pdo = new PDO("mysql:host=localhost;dbname=mysql","admin","123456"); //远程用root不行？
  $dbh = new PDO("mysql:host=localhost", "root", "");
  $dbh->exec("CREATE DATABASE IF NOT EXISTS `cjltest` DEFAULT CHARSET utf8 COLLATE utf8_general_ci;
                CREATE USER 'root'@'localhost' IDENTIFIED BY '';
                GRANT ALL ON `cjltest`.* TO 'root'@'localhost';
                FLUSH PRIVILEGES;") 
        or die(print_r($dbh->errorInfo(), true));
 
	$dbh=null;	
}
//读数据库,返回数组
function dbr() { 
$pdo = new PDO("mysql:host=localhost;dbname=mysql","admin","123456"); 
$stmt = $pdo->query('SELECT * FROM user');
$arr1=$stmt->fetch();
var_dump($arr1);
$arr=$stmt->fetchAll();
var_dump($arr);
$stmt = null; // doing this is mandatory for connection to get closed
$pdo = null;
}
//从sql文件生成数据库表
//为方便，db.sql中不允许有注释，并去掉最后一个分号
function dbsql() { 
$pdo = new PDO("mysql:host=localhost;dbname=cjltest","admin","123456"); 
$pdo->query("set names utf8");//否则为乱码
$sqlStr=file_get_contents('db.sql');
  //通过sql语法的语句分割符进行分割
        $arr = explode(";",trim($sqlStr));	
		//执行sql语句
		var_dump($arr);
foreach ($arr as $value) {
    $pdo->exec($value);
}
$pdo = null;
}

//向数据库表插入数据
function dbins() { 
$pdo = new PDO("mysql:host=localhost;dbname=cjltest","admin","123456"); 
//准备SQL语句
$sql = "INSERT INTO c (name,sequence) value (:name,:sequence)";//省掉了自动编号字段
$stmt = $pdo->prepare($sql);
//准备数据
$arr=array(

':name'=>2,
':sequence'=>3);
$stmt->execute($arr);
var_dump($pdo->lastInsertId());
$stmt = null; // doing this is mandatory for connection to get closed
$pdo = null;
}

//更新数据库表的数据
function dbu() { 
$pdo = new PDO("mysql:host=localhost;dbname=cjltest","admin","123456"); 
//准备SQL语句
$sql = "UPDATE c SET name=:name,sequence=:sequence WHERE cid=1";//省掉了自动编号字段
$stmt = $pdo->prepare($sql);
//准备数据
$arr=array(
':name'=>11,
':sequence'=>22);
$stmt->execute($arr);
$stmt = null; // doing this is mandatory for connection to get closed
$pdo = null;
}
//删除数据库表的数据
function dbdel() { 
$pdo = new PDO("mysql:host=localhost;dbname=cjltest","admin","123456"); 
//准备SQL语句
$sql = "DELETE FROM c WHERE cid>:cid";//省掉了自动编号字段
$stmt = $pdo->prepare($sql);
//准备数据
$arr=array(
':cid'=>30);
$stmt->execute($arr);
var_dump($pdo->lastInsertId());
$stmt = null; // doing this is mandatory for connection to get closed
$pdo = null;
}
//session
function sess() {
  session_start();
if (!isset($_SESSION['count'])) {
  $_SESSION['count'] = 0;
} else {
  $_SESSION['count']++;
}
var_dump($_SESSION['count']);
}
function cooki() {
  // set the cookies
setcookie("mycookie[three]",urlencode("cookiethree三"));
setcookie("mycookie[two]", urlencode("cookietwo二"));
setcookie("mycookie[one]", urlencode("cookieone一"));

// after the page reloads, print them out
if (isset($_COOKIE['mycookie'])) {
    foreach ($_COOKIE['mycookie'] as $name => $value) {
        $name = htmlspecialchars($name);
        $value = htmlspecialchars(urldecode($value));
        echo "$name : $value <br />\n";
    }
}
}
//文件上传，此处不含上传界面
function fileup() {
	
  if ((($_FILES["file"]["type"] == "image/gif")
|| ($_FILES["file"]["type"] == "image/jpeg")
|| ($_FILES["file"]["type"] == "image/pjpeg"))
&& ($_FILES["file"]["size"] < 20000000))
  {
  if ($_FILES["file"]["error"] > 0)
    {
    echo "Return Code: " . $_FILES["file"]["error"] . "<br />";
    }
  else
    {
    echo "Upload: " . $_FILES["file"]["name"] . "<br />";
    echo "Type: " . $_FILES["file"]["type"] . "<br />";
    echo "Size: " . ($_FILES["file"]["size"] / 1024) . " Kb<br />";
    echo "Temp file: " . $_FILES["file"]["tmp_name"] . "<br />";

    if (file_exists("upload/" . $_FILES["file"]["name"]))
      {
      echo $_FILES["file"]["name"] . " already exists. ";
      }
    else
      {
      move_uploaded_file($_FILES["file"]["tmp_name"],
      "upload/" . $_FILES["file"]["name"]);
      echo "Stored in: " . "upload/" . $_FILES["file"]["name"];
      }
    }
  }
else
  {
  echo "Invalid file";
  }
}