PHP namespace namespace definition and import use case analysis-PHP Tutorial-php.cn

This time I will bring youPHP namespacenamespace definition and import use case analysis, PHP namespace namespace definition and import useWhat are the precautions, the following is a practical case , let’s take a look.

In PHP, functions or classes with the same name are not allowed. In order toprevent repeated conflictsin class names or function names defined by programmers in the project, the concept of namespace was introduced in PHP5.3.

1. Namespace means dividing the code into different spaces. The class names in different spaces are independent of each other and do not conflict with each other.Multiple namespaces can exist in a php file, and there cannot be any code before the first namespace. The code after the content space declaration belongs to this namespace, for example:


        
         Copy after login

2. When calling classes or methods in different spaces, the namespace must be specified.For example:

'; } } function Person(){ return 'You must stay here!'; }; namespace Student; class Person{ function construct(){ echo 'I want to play!
'; } } new Person(); //本空间（Student空间） new \Teacher\Person(); //Teacher空间 new \Student\Person(); //Student空间 echo \Teacher\Person(); //Teacher空间下Person函数

Copy after login

Output:

I want to play! Please study! I want to play! You must stay here!

Copy after login

3. Other files introduced into the namespace will not belong to this namespace, but belong to the public space or the file itself. namespace.Example:

First define a 1.php and 2.php file:

'; } }

Copy after login


        
         Copy after login

'; } }

Copy after login


        
         Copy after login

4. Let’s look at how to use use:(after useQuotecan be abbreviated)

namespace School\Parents; class Man{ function construct(){ echo 'Listen to teachers!
'; } } namespace School\Teacher; class Person{ function construct(){ echo 'Please study!
'; } } namespace School\Student; class Person{ function construct(){ echo 'I want to play!
'; } } new Person(); //输出I want to play! new \School\Teacher\Person(); //输出Please study! new Teacher\Person(); //报错 ---------- use School\Teacher; new Teacher\Person(); //输出Please study! ---------- use School\Teacher as Tc; new Tc\Person(); //输出Please study! ---------- use \School\Teacher\Person; new Person(); //报错 ---------- use \School\Parent\Man; new Man(); //报错

Copy after login

I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the php Chinese website!