PHP語言高級(jí)教程

PHP語言高級(jí)教程PHP是一種廣泛使用的服務(wù)器端腳本語言，特別適合Web開發(fā)。以下是一個(gè)PHP語言的高級(jí)教程，涵蓋了一些高級(jí)特性和最佳實(shí)踐。1.面向?qū)ο缶幊蹋∣OP）1.1類和對(duì)象classCar{//屬性public$brand;public$model;//構(gòu)造函數(shù)publicfunction__construct($brand,$model){$this->brand=$brand;$this->model=$model;}//方法publicfunctiondisplayInfo(){return"Thiscarisa".$this->brand."".$this->model.".";}}//創(chuàng)建對(duì)象$myCar=newCar("Toyota","Corolla");echo$myCar->displayInfo();1.2繼承classElectricCarextendsCar{public$batteryLife;publicfunction__construct($brand,$model,$batteryLife){parent::__construct($brand,$model);$this->batteryLife=$batteryLife;}publicfunctiondisplayBatteryLife(){return"Thiselectriccarhasabatterylifeof".$this->batteryLife."hours.";}}$myElectricCar=newElectricCar("Tesla","ModelS",100);echo$myElectricCar->displayInfo();echo$myElectricCar->displayBatteryLife();1.3訪問控制public：公開的，可以在任何地方訪問。protected：受保護(hù)的，只能在類內(nèi)部和子類中訪問。private：私有的，只能在類內(nèi)部訪問。classExample{public$publicVar="Public";protected$protectedVar="Protected";private$privateVar="Private";publicfunctiondisplayVars(){echo$this->publicVar."<br>";echo$this->protectedVar."<br>";echo$this->privateVar."<br>";}}$example=newExample();echo$example->publicVar."<br>";//可以訪問//echo$example->protectedVar;//報(bào)錯(cuò)//echo$example->privateVar;//報(bào)錯(cuò)$example->displayVars();//可以訪問2.異常處理2.1基本異常處理functiondivide($numerator,$denominator){if($denominator==0){thrownewException("Divisionbyzero.");}return$numerator/$denominator;}try{echodivide(10,0);}catch(Exception$e){echo"Caughtexception:".$e->getMessage();}2.2自定義異常classCustomExceptionextendsException{publicfunctionerrorMessage(){return"CustomException:".$this->getMessage();}}functioncheckNumber($number){if($number>5){thrownewCustomException("Numberisgreaterthan5.");}returntrue;}try{checkNumber(10);}catch(CustomException$e){echo$e->errorMessage();}3.命名空間（Namespace）3.1基本使用namespaceMyProject;classMyClass{publicfunctionsayHello(){echo"HellofromMyClass!";}}$myClass=new\MyProject\MyClass();$myClass->sayHello();3.2使用別名namespaceMyProject;classMyClass{publicfunctionsayHello(){echo"HellofromMyClass!";}}namespaceAnotherProject;useMyProject\MyClassasAnotherClass;$myClass=newAnotherClass();$myClass->sayHello();4.自動(dòng)加載（Autoloading）4.1使用spl_autoload_registerspl_autoload_register(function($class_name){include$class_name.'.php';});$myClass=newMyClass();$myClass->sayHello();4.2使用Composer自動(dòng)加載創(chuàng)建composer.json文件：{"autoload":{"psr-4":{"MyProject\\":"src/"}}}運(yùn)行composerinstall生成自動(dòng)加載文件。在代碼中使用：require'vendor/autoload.php';useMyProject\MyClass;$myClass=newMyClass();$myClass->sayHello();5.數(shù)據(jù)庫操作（PDO）5.1連接數(shù)據(jù)庫$host='localhost';$dbname='testdb';$username='root';$password='';try{$conn=newPDO("mysql:host=$host;dbname=$dbname",$username,$password);$conn->setAttribute(PDO::ATTR_ERRMODE,PDO::ERRMODE_EXCEPTION);echo"Connectedsuccessfully";}catch(PDOException$e){echo"Connectionfailed:".$e->getMessage();}5.2執(zhí)行查詢$stmt=$conn->prepare("SELECT*FROMusersWHEREid=:id");$stmt->execute(['id'=>1]);$user=$stmt->fetch(PDO::FETCH_ASSOC);print_r($user);5.3插入數(shù)據(jù)$stmt=$conn->prepare("INSERTINTOusers(name,email)VALUES(:name,:email)");$stmt->execute(['name'=>'JohnDoe','email'=>'john@']);echo"Newrecordcreatedsuccessfully";6.文件操作6.1讀取文件$file=fopen("example.txt","r")ordie("Unabletoopenfile!");echofread($file,filesize("example.txt"));fclose($file);6.2寫入文件$file=fopen("example.txt","w")ordie("Unabletoopenfile!");$txt="Hello,World!\n";fwrite($file,$txt);fclose($file);7.會(huì)話管理（Session）7.1啟動(dòng)會(huì)話session_start();$_SESSION['username']='JohnDoe';echo"Sessionstartedandusernameset.";7.2讀取會(huì)話數(shù)據(jù)session_start();if(isset($_SESSION['username'])){echo"Welcome".$_SESSION['username'];}else{echo"Sessionnotset.";}7.3銷毀會(huì)話session_start();session_unset();session_destroy();echo"Sessiondestroyed.";8.高級(jí)特性8.1匿名函數(shù)（閉包）$greet=function($name){return"Hello,$name!";};echo$greet("John");8.2生成器（Generators）functiongenerateNumbers($start,$end){for($i=$start;$i<=$end;$i++){yield$i;}}foreach(generateNumbers(1,5)as$number){echo$number."";}8.3反射（Reflection）classMyClass{publicfunctionmyMethod($param){return"Hello,$param!";}}$reflection=newReflectionClass('MyClass');$method=$reflection->getMethod('myMethod');echo$method->invoke(newMyClass(),'World');9.安全最佳實(shí)踐9.1防止SQL注入使用PDO預(yù)處理語句：$stmt=$conn->prepare("SELECT*FROMusersWHEREid=:id");$stmt->execute(['id'=>$id]);9.2防止XSS攻擊使用htmlspecialchars函數(shù)：echohtmlspecialchars($userInput,ENT_QUOTES,'UTF-8');9.3密碼哈希使用password_hash和password_verify：$password="mypassword";$hashedPassword=password_hash($password,PASSWORD_DEFAULT);if(password_verify($password,$hashedPassword)){echo"Passwordisvalid!";}else{echo"Invalidpassword!";}10.性能優(yōu)化10.1使用OPcache在php.ini中啟用OPcache：opcache.enable=1opcache.enable_cli=1opcache.memory_consumption=128opcache.max_accelerated_files=4000opcache.validate_timestamps=010.2使用緩存使用Memcached或Redis緩存數(shù)據(jù)：$memcached=newMemcached();$memcache