PHP object-oriented development-magic Functions

In php, magic functions include tostring, call, clone, and autoload. I hope this tutorial will be helpful to all of you.

Object-Oriented development Summary

1. Description and configuration of the object. (It can be understood as the output text description of the object)
2. processing an object method. (It can be understood that, when an exception occurs, a more user-friendly error message is customized)
3. Application of the cloned object. (It can be understood that, on the original object, the same object is cloned, And the other object is the same .)
4. Methods for automatically loading objects. (Can be understood as reference)

1. Object Description and Configuration

Method Name __tostring ()
Format:

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Class My { Function _ tostring (){ Return "write the text description of this class here"; // if you want to use return, echo will fail. } } $ P = new My (); Echo $ p;

Instance:

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<? Php Class My { Function _ toString (){ Return "is used to protect the Earth. "; } } $ P = new My (); Echo $ p; ?>

2. Exception Handling of object Methods

Exception Handling for calling some non-existing object methods is that the program runs normally.
Method Name: __ call ($ funname, $ arr_value)
Format:

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Class My { Function _ call ($ n, $ v ){ Echo "incorrect method name:". $ n; Echo "Incorrect Parameter:". $ v; } }

Instance:

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<? Php Class My { Function _ toString (){ Return "is used to protect the Earth. "; } Function _ call ($ n, $ v ){ Echo "incorrect method <B>". $ n. "</B> <br/> "; Echo "incorrect value <B>". print_r ($ v). "</B>"; // The value is transmitted in array mode, so print_r is used. } } $ P = new My (); $ P-> demo ("first", 6 ); ?>

3. Object cloning

By cloning, you can generate two identical objects in the memory or upgrade the original object. (Not a simple assignment, but two memory blocks are opened in the memory. The cloned and cloned two objects are the same as the two Property methods)
Method Name: __ clone ()
Keyword: clone
Format:

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Class My { Function _ clone (){ Echo "functions automatically called during cloning "; } } $ A = new My (); $ B = clone $;

Instance:

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<? Php Class My { Public $ name = ""; Function _ toString (){ Return "is used to protect the Earth. "; } Function _ call ($ n, $ v ){ Echo "incorrect method <B>". $ n. "</B> <br/> "; Echo "incorrect value <B>". print_r ($ v). "</B>"; // The value is transmitted in array mode, so print_r is used. } } $ P = new My (); $ B = clone $ p; Echo $ B-> name = "pig ". "<br/>"; // This is the cloned and modified object. If $ B = $ p is used, modify $ B-> name = "Pigsty head, the $ p output will also be modified. Echo $ p-> name; // This is the original object. It has been cloned by $ B. Others are the same, but they are independent. ?>

4. Methods for automatically loading objects

Get the object name quickly and load it into the current page automatically
Method Name __autoload ()
Format:

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Function _ autoload ($ class_n ){ Include ($ class_n. ". php "); } $ P = new MyPc (); // The automatic call is executed as follows $ D = new demo (); // include ("mypc. php ")

Instance:

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<? Php Function _ aotoload ($ class_name ){ Include ($ class_name. ". php"); // write it outside the class. } $ P = new class_name (); // The class name instantiated here is replaced by the above function variable $ class_name, which is very convenient. ?>