PHP语言高级教程

PHP语言高级教程PHP是一种广泛使用的服务器端脚本语言，特别适合Web开发。以下是一个PHP语言的高级教程，涵盖了一些高级特性和最佳实践。1.面向对象编程（OOP）1.1类和对象classCar{//属性public$brand;public$model;//构造函数publicfunction__construct($brand,$model){$this->brand=$brand;$this->model=$model;}//方法publicfunctiondisplayInfo(){return"Thiscarisa".$this->brand."".$this->model.".";}}//创建对象$myCar=newCar("Toyota","Corolla");echo$myCar->displayInfo();1.2继承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访问控制public：公开的，可以在任何地方访问。protected：受保护的，只能在类内部和子类中访问。private：私有的，只能在类内部访问。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>";//可以访问//echo$example->protectedVar;//报错//echo$example->privateVar;//报错$example->displayVars();//可以访问2.异常处理2.1基本异常处理functiondivide($numerator,$denominator){if($denominator==0){thrownewException("Divisionbyzero.");}return$numerator/$denominator;}try{echodivide(10,0);}catch(Exception$e){echo"Caughtexception:".$e->getMessage();}2.2自定义异常classCustomExceptionextendsException{publicfunctionerrorMessage(){return"CustomException:".$this->getMessage();}}functioncheckNumber($number){if($number>5){thrownewCustomException("Numberisgreaterthan5.");}returntrue;}try{checkNumber(10);}catch(CustomException$e){echo$e->errorMessage();}3.命名空间（Namespace）3.1基本使用namespaceMyProject;classMyClass{publicfunctionsayHello(){echo"HellofromMyClass!";}}$myClass=new\MyProject\MyClass();$myClass->sayHello();3.2使用别名namespaceMyProject;classMyClass{publicfunctionsayHello(){echo"HellofromMyClass!";}}namespaceAnotherProject;useMyProject\MyClassasAnotherClass;$myClass=newAnotherClass();$myClass->sayHello();4.自动加载（Autoloading）4.1使用spl_autoload_registerspl_autoload_register(function($class_name){include$class_name.'.php';});$myClass=newMyClass();$myClass->sayHello();4.2使用Composer自动加载创建composer.json文件：{"autoload":{"psr-4":{"MyProject\\":"src/"}}}运行composerinstall生成自动加载文件。在代码中使用：require'vendor/autoload.php';useMyProject\MyClass;$myClass=newMyClass();$myClass->sayHello();5.数据库操作（PDO）5.1连接数据库$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:".$e->getMessage();}5.2执行查询$stmt=$conn->prepare("SELECT*FROMusersWHEREid=:id");$stmt->execute(['id'=>1]);$user=$stmt->fetch(PDO::FETCH_ASSOC);print_r($user);5.3插入数据$stmt=$conn->prepare("INSERTINTOusers(name,email)VALUES(:name,:email)");$stmt->execute(['name'=>'JohnDoe','email'=>'john@']);echo"Newrecordcreatedsuccessfully";6.文件操作6.1读取文件$file=fopen("example.txt","r")ordie("Unabletoopenfile!");echofread($file,filesize("example.txt"));fclose($file);6.2写入文件$file=fopen("example.txt","w")ordie("Unabletoopenfile!");$txt="Hello,World!\n";fwrite($file,$txt);fclose($file);7.会话管理（Session）7.1启动会话session_start();$_SESSION['username']='JohnDoe';echo"Sessionstartedandusernameset.";7.2读取会话数据session_start();if(isset($_SESSION['username'])){echo"Welcome".$_SESSION['username'];}else{echo"Sessionnotset.";}7.3销毁会话session_start();session_unset();session_destroy();echo"Sessiondestroyed.";8.高级特性8.1匿名函数（闭包）$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$method->invoke(newMyClass(),'World');9.安全最佳实践9.1防止SQL注入使用PDO预处理语句：$stmt=$conn->prepare("SELECT*FROMusersWHEREid=:id");$stmt->execute(['id'=>$id]);9.2防止XSS攻击使用htmlspecialchars函数：echohtmlspecialchars($userInput,ENT_QUOTES,'UTF-8');9.3密码哈希使用password_hash和password_verify：$password="mypassword";$hashedPassword=password_hash($password,PASSWORD_DEFAULT);if(password_verify($password,$hashedPassword)){echo"Passwordisvalid!";}else{echo"Invalidpassword!";}10.性能优化10.1使用OPcache在php.ini中启用OPcache：opcache.enable=1opcache.enable_cli=1opcache.memory_consumption=128opcache.max_accelerated_files=4000opcache.validate_timestamps=010.2使用缓存使用Memcached或Redis缓存数据：$memcached=newMemcached();$memcache