A complete example of XML operations in Java

A complete example of XML operations in Java-W3C dom

This is an example of using Java W3C dom for XML, including basic operations for querying, adding, modifying, deleting, and saving. A complete description of the entire XML operation process. It is suitable for users who are new to Java XML operations for reference and learning.

Suppose there is an XML file: test1.xml

 

<? XML version = "1.0" encoding = "UTF-8"?>
<Books>
<Book>
<Name> Harry Potter </Name>
<Price> 10 </price>
<Memo> This is a nice book. </Memo>
</Book>
<Book id = "B02">
<Name> Romance of the Three Kingdoms </Name>
<Price> 10 </price>
<Memo> one of the four famous books. </Memo>
</Book>
<Book id = "b03">
<Name> region </Name>
<Price> 6 </price>
<Memo> one of the four famous books. </Memo>
</Book>
<Book id = "b04">
<Name> redhouse </Name>
<Price> 5 </price>
<Memo> one of the four famous books. </Memo>
</Book>
</Books>

 

Below is test. Java

 

Import java. Io. file;
Import java. Io. filenotfoundexception;
Import java. Io. fileoutputstream;
Import java. Io. ioexception;

Import org. W3C. Dom .*;
Import org. xml. Sax. saxexception;

Import javax. xml. parsers .*;
Import javax. xml. Transform .*;
Import javax. xml. Transform. Dom. domsource;
Import javax. xml. Transform. Stream .*;
Import javax. xml. XPath .*;

Public class test ...{
Public static void main (string [] ARGs )...{
Documentbuilderfactory factory = documentbuilderfactory. newinstance ();
Element thebook = NULL, theelem = NULL, root = NULL;
Try ...{
Factory. setignoringelementcontentwhitespace (true );

Documentbuilder DB = factory. newdocumentbuilder ();
Document xmldoc = dB. parse (new file ("test1.xml "));
Root = xmldoc. getdocumentelement ();

// --- Create a new book ----
Thebook = xmldoc. createelement ("book ");
Theelem = xmldoc. createelement ("name ");
Theelem. settextcontent ("new book ");
Thebook. appendchild (theelem );

Theelem = xmldoc. createelement ("price ");
Theelem. settextcontent ("20 ");
Thebook. appendchild (theelem );

Theelem = xmldoc. createelement ("memo ");
Theelem. settextcontent ("a better book. ");
Thebook. appendchild (theelem );
Root. appendchild (thebook );
System. Out. println ("--- create a new book ----");
Output (xmldoc );
// --- Create a new book ----

// --- Make some changes to Harry Potter. ----
// --- Query for Harry Potter ----
Thebook = (element) selectsinglenode ("/books/book [name = ''harry Potter''] ", root );
System. Out. println ("--- query for Harry Potter ----");
Output (thebook );
// --- Modify the price of this book at this time -----
Thebook. getelementsbytagname ("price"). Item (0). settextcontent ("15"); // getelementsbytagname returns nodelist, so keep up with item (0)
System. Out. println ("--- modify the price of this book at this time ----");
Output (thebook );
// --- You also want to add an attribute ID with the value B01 ----
Thebook. setattribute ("ID", "B01 ");
System. Out. println ("--- you also want to add an attribute ID with the value B01 ----");
Output (thebook );
// --- Modify Harry Potter. ----

// --- Delete the book Romance of the Three Kingdoms with the ID attribute ----
Thebook = (element) selectsinglenode ("/books/book [@ ID = ''b02'']", root );
System. Out. println ("--- use the ID attribute to delete the book" Romance of the Three Kingdoms ----");
Output (thebook );
Thebook. getparentnode (). removechild (thebook );
System. Out. println ("--- XML after deletion ----");
Output (xmldoc );

// --- Delete all books whose prices are less than 10 ----
Nodelist somebooks = selectnodes ("/books/book [price <10]", root );
System. Out. println ("--- delete all books with prices less than 10 ---");
System. Out. println ("--- eligible books include" + somebooks. getlength () +. ---");
For (INT I = 0; I <somebooks. getlength (); I ++ )...{
Somebooks. Item (I). getparentnode (). removechild (somebooks. Item (I ));
}
Output (xmldoc );

Savexml ("test10000edited.xml", xmldoc );
} Catch (parserconfigurationexception e )...{
E. printstacktrace ();
} Catch (saxexception e )...{
E. printstacktrace ();
} Catch (ioexception e )...{
E. printstacktrace ();
}
}

Public static void output (node)... {// output the XML string of node to the console
Transformerfactory transfactory = transformerfactory. newinstance ();
Try ...{
Transformer transformer = transfactory. newtransformer ();
Transformer. setoutputproperty ("encoding", "gb2312 ");
Transformer. setoutputproperty ("indent", "yes ");

Domsource source = new domsource ();
Source. setnode (node );
Streamresult result = new streamresult ();
Result. setoutputstream (system. Out );

Transformer. Transform (source, result );
} Catch (transformerconfigurationexception e )...{
E. printstacktrace ();
} Catch (transformerexception e )...{
E. printstacktrace ();
}
}

Public static node selectsinglenode (string Express, object source)... {// find the node and return the first qualified Node
Node result = NULL;
Xpathfactory = xpathfactory. newinstance ();
XPath = xpathfactory. newxpath ();
Try ...{
Result = (node) XPath. Evaluate (Express, source, xpathconstants. node );
} Catch (xpathexpressionexception e )...{
E. printstacktrace ();
}

Return result;
}

Public static nodelist selectnodes (string Express, object source)... {// find a node and return a node set that meets the conditions.
Nodelist result = NULL;
Xpathfactory = xpathfactory. newinstance ();
XPath = xpathfactory. newxpath ();
Try ...{
Result = (nodelist) XPath. Evaluate (Express, source, xpathconstants. nodeset );
} Catch (xpathexpressionexception e )...{
E. printstacktrace ();
}

Return result;
}

Public static void savexml (string filename, document DOC)... {// output document to file
Transformerfactory transfactory = transformerfactory. newinstance ();
Try ...{
Transformer transformer = transfactory. newtransformer ();
Transformer. setoutputproperty ("indent", "yes ");

Domsource source = new domsource ();
Source. setnode (DOC );
Streamresult result = new streamresult ();
Result. setoutputstream (New fileoutputstream (filename ));

Transformer. Transform (source, result );
} Catch (transformerconfigurationexception e )...{
E. printstacktrace ();
} Catch (transformerexception e )...{
E. printstacktrace ();
} Catch (filenotfoundexception e )...{
E. printstacktrace ();
}
}
}

 

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