How to call methods of other classes in PHP

PHP is a very popular open source server-side scripting language that is widely used in today's web development field. In PHP, we often need to call methods of other classes to implement some complex functions. This article will introduce how to call methods of other classes in PHP.

In PHP, we can use the following methods to call methods of other classes:

1. Instantial objects

Use instantiated objects Methods can call public methods of other classes.

Example:

class Test {
   public function foo() {
       echo "hello world!";
   }
}

$test = new Test();
$test->foo(); // "hello world!"

In the above example, we defined a Test class, which has a public method foo(). We can call the foo() method of the Test class by instantiating it.

2. Use static methods

Using static methods allows you to directly call methods in the class without creating an instance of the class.

Example:

class Test {
   public static function foo() {
       echo "hello world!";
   }
}

Test::foo(); // "hello world!"

In the above example, we defined a Test class, which has a static method foo(). We can directly call the foo() method of this class through Test::foo() without creating an instance of the Test class.

3. Using inheritance

Using inheritance, you can use the methods of the parent class in a class.

Example:

class Parent {
   public function foo() {
       echo "hello world!";
   }
}

class Child extends Parent {
   
}

$child = new Child();
$child->foo(); // "hello world!"

In the above example, we defined a Parent class and a Child class. Child class inherits from Parent class. We can call the foo() method of the Parent class in the Child class.

4. Using Trait

Use Trait to share methods between multiple classes.

Example:

trait TestTrait {
   public function foo() {
       echo "hello world!";
   }
}

class Test {
   use TestTrait;
}

$test = new Test();
$test->foo(); // "hello world!"

In the above example, we defined a TestTrait Trait and used it in the Test class. By using Trait, the foo() method in TestTrait can also be called in the Test class.

Summary:

In PHP, we can use instantiated objects, static methods, inheritance and Traits to call methods of other classes. These methods have their own application scenarios, and developers should choose the appropriate method according to the specific situation.

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