Php encountered an error when reading xml documents with entity symbols. how can this problem be solved?

Php encountered an error when reading the xml document object symbols, such as & lt; name & gt; aa & amp; nbsp; bb & lt; name & gt; & nbsp; this warning is reported when the entity symbol of this grid exists in the middle (!) Warning: DOMDocument: load () [domdocument. load]: Entitynbspnotdefinedinfile: An error occurred while reading xml documents from xm php.
For example Aa bb
When the entity symbol of this lattice exists in the middle
This warning is reported.
(! ) Warning: DOMDocument: load () [domdocument. load]: Entity 'nbsp 'not defined in file:

Reading xml documents is like this.
$ Xml = new DOMDocument ("1.0", "UTF-8 ");
$ Xml-> load ('myxml. XML ');

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It is good to discover the problem by yourself. since it is not allowed to appear, how are you going to solve it?
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From php Manual

PHP code

When using loadXML () to parse a string that contains entity references (e.g .,), be sure that those entity references are properly declared through the use of a DOCTYPE declaration; otherwise, loadXML () will not be able to interpret the string. example:
  
This is a non-breaking space.
XML; $ dd1 = new DOMDocument (); $ dd1-> loadXML ($ str); echo $ dd1-> saveXML ();?> Given the above code, PHP will issue a Warning about the entity 'nbsp 'not being properly declared. also, the call to saveXML () will return nothing but a trimmed-down version of the original processing instruction... everything else is gone, and all because of the undeclared entity. instead, explicitly declare the entity first:
  ]>
This is a non-breaking space.
XML; $ dd2 = new DOMDocument (); $ dd2-> loadXML ($ str); echo $ dd2-> saveXML ();?> Since the 'nbsp 'entity is defined in the DOCTYPE, PHP no longer issues that Warning; the string is now well-formed, and loadXML () understands it perfectly. you can also use references to external DTDs in the same way (e.g .,), Which is fig important if you need to do this for each different events Ents with each different possible entities. also, as a sidenote... entity references created by createEntityReference () do not need this kind of explicit declaration.
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Congratulations, lz .~~
Thanks ZT_king
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<> And & cannot appear